draft-ietf-sigtran-m2ua-04.txt   draft-ietf-sigtran-m2ua-05.txt 
Network Working Group Ken Morneault Network Working Group Ken Morneault
INTERNET-DRAFT Cisco Systems INTERNET-DRAFT Ram Dantu
Cisco Systems
Mallesh Kalla Mallesh Kalla
Telcordia Telcordia
Greg Sidebottom Greg Sidebottom
Nortel Networks Nortel Networks
Ram Dantu
IPMobile
Tom George Tom George
Alcatel Alcatel
Expires in six months March 2000 Expires in six months Nov 2000
SS7 MTP2-User Adaptation Layer SS7 MTP2-User Adaptation Layer
<draft-ietf-sigtran-m2ua-04.txt> <draft-ietf-sigtran-m2ua-05.txt>
Status of This Memo Status of This Memo
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Abstract Abstract
This Internet Draft defines a protocol for backhauling of SS7 MTP2 This Internet Draft defines a protocol for backhauling of SS7 MTP2
User signaling messages over IP using the Simple Control Transmission User signaling messages over IP using the Stream Control
Protocol (SCTP). This protocol would be used between a Signaling Transmission Protocol (SCTP). This protocol would be used between a
Gateway (SG) and Media Gateway Controller (MGC). It is assumed that Signaling Gateway (SG) and Media Gateway Controller (MGC). It is
the SG receives SS7 signaling over a standard SS7 interface using the assumed that the SG receives SS7 signaling over a standard SS7
SS7 Message Transfer Part (MTP) to provide transport. The Signaling interface using the SS7 Message Transfer Part (MTP) to provide
Gateway would act as a Signaling Link Terminal. transport. The Signaling Gateway would act as a Signaling Link
Terminal.
TABLE OF CONTENTS TABLE OF CONTENTS
1. Introduction..............................................2 1. Introduction..............................................2
1.1 Scope..................................................2 1.1 Scope..................................................2
1.2 Terminology............................................3 1.2 Terminology............................................3
1.3 Signaling Transport Architecture.......................3 1.3 Signaling Transport Architecture.......................3
1.4 Services Provide by the M2UA Adaptation Layer..........6 1.4 Services Provide by the M2UA Adaptation Layer..........6
1.5 Function Provided by the M2UA Layer....................8 1.5 Function Provided by the M2UA Layer....................8
1.6 Definition of the M2UA Boundaries......................9 1.6 Definition of the M2UA Boundaries......................9
skipping to change at page 3, line 9 skipping to change at page 3, line 9
6. Security.................................................30 6. Security.................................................30
7. IANA Considerations......................................31 7. IANA Considerations......................................31
8. Acknowledgements.........................................31 8. Acknowledgements.........................................31
9. References...............................................32 9. References...............................................32
10. Author's Addresses.......................................33 10. Author's Addresses.......................................33
1. Introduction 1. Introduction
1.1 Scope 1.1 Scope
There is a need for SCN signaling protocol delivery from an Signaling There is a need for Switched Circuit Network SCN signaling protocol
Gateway (SG) to a Media Gateway Controller (MGC) or IP Signaling Point delivery from an Signaling Gateway (SG) to a Media Gateway
(IPSP). The delivery mechanism should meet the following criteria: Controller (MGC) or IP Signaling Point (IPSP). The delivery
mechanism SHOULD meet the following criteria:
* Support for MTP Level 2 / MTP Level 3 interface boundary * Support for MTP Level 2 / MTP Level 3 interface boundary
* Support for communication between Layer Management modules on SG and * Support for communication between Layer Management modules on SG
MGC and MGC
* Support for management of active associations between the SG and MGC * Support for management of active associations between the SG and MGC
In other words, the Signaling Gateway will transport MTP Level 3 In other words, the Signaling Gateway will transport MTP Level 3
messages to a Media Gateway Controller (MGC) or IP Signaling Point messages to a Media Gateway Controller (MGC) or IP Signaling Point
(IPSP). In the case of delivery from an SG to an IPSP, both the SG and (IPSP). In the case of delivery from an SG to an IPSP, both the SG and
IPSP function as traditional SS7 nodes using the IP network as a new IPSP function as traditional SS7 nodes using the IP network as a new
type of SS7 link. This allows for full MTP Level 3 message handling type of SS7 link. This allows for full MTP Level 3 message handling
and network management capabilities. and network management capabilities.
1.2 Terminology 1.2 Terminology
MTP2-User - A protocol that normally uses the services of MTP Level 2 MTP2-User - A protocol that normally uses the services of MTP Level 2
(i.e. MTP3). (i.e. MTP3).
Interface - For the purposes of this document, an interface is a SS7 Interface - For the purposes of this document, an interface is a SS7
signaling link. signaling link.
Association - An association refers to a SCTP association. The
association will provide the transport for the delivery of protocol
data units for one or more interfaces.
Backhaul - Refers to the transport of signaling from the point of Backhaul - Refers to the transport of signaling from the point of
interface for the associated data stream (i.e., SG function in the MGU) interface for the associated data stream (i.e., SG function in the MGU)
back to the point of call processing (i.e., the MGCU), if this is not back to the point of call processing (i.e., the MGCU), if this is not
local [4]. local [4].
Association - An association refers to a SCTP association. The
association will provide the transport for the delivery of protocol
data units for one or more interfaces.
Stream - A stream refers to an SCTP stream; a uni-directional logical
channel established from one SCTP endpoint to another associated SCTP
endpoint, within which all user messages are delivered in-sequence
except for those submitted to the un-ordered delivery service.
Interface Identifier - The Interface Identifier identifies the physical
interface at the SG for which the signaling messages are sent/received.
The format of the Interface Identifier parameter can be text or integer,
the values of which are assigned according to network operator policy.
The values used are of local significance only, coordinated between the
SG and ASP.
Application Server (AS) - A logical entity serving a specific application Application Server (AS) - A logical entity serving a specific application
instance. An example of an Application Server is a MGC handling the instance. An example of an Application Server is a MGC handling the
MTP Level 3 and call processing for SS7 links terminated by the MTP Level 3 and call processing for SS7 links terminated by the
Signaling Gateways. Practically speaking, an AS is modeled at the SG Signaling Gateways. Practically speaking, an AS is modeled at the SG
as an ordered list of one or more related Application Server Processes as an ordered list of one or more related Application Server Processes
(e.g., primary, secondary, tertiary, ...). (e.g., primary, secondary, tertiary, ...).
Application Server Process (ASP) - A process instance of an Application Application Server Process (ASP) - A process instance of an Application
Server. Examples of Application Server Processes are primary or backup Server. Examples of Application Server Processes are primary or backup
MGC instances. MGC instances.
Application Server Process Path (ASP Path or just Path) - A Path to a
remote Application Server Process instance. A Path maps 1:1 to an SCTP
association.
Fail-over - The capability to re-route signaling traffic as required Fail-over - The capability to re-route signaling traffic as required
to an alternate Application Server Process, or group of ASPs, within to an alternate Application Server Process, or group of ASPs, within
an Application Server in the event of failure or unavailability of a an Application Server in the event of failure or unavailability of a
currently used Application Server Process. Fail-back may apply upon currently used Application Server Process. Fail-back MAY apply upon
the return to service of a previously unavailable Application Server the return to service of a previously unavailable Application Server
Process. Process.
Signaling Link Terminal (SLT) - Refers to the means of performing all Signaling Link Terminal (SLT) - Refers to the means of performing all
of the functions defined at MTP level 2 regardless of their of the functions defined at MTP level 2 regardless of their
implementation [2]. implementation [2].
Network Byte Order: Most significant byte first, a.k.a Big Endian.
Layer Management - Layer Management is a nodal function in an SG or Layer Management - Layer Management is a nodal function in an SG or
ASP that handles the inputs and outputs between the M2UA layer and a ASP that handles the inputs and outputs between the M2UA layer and a
local management entity. local management entity.
Host - The computing platform that the ASP process is running on. Network Byte Order: Most significant byte first, a.k.a Big Endian.
Stream - A stream refers to an SCTP stream. Host - The computing platform that the ASP process is running on.
1.3 Signaling Transport Architecture 1.3 M2UA Overview
The framework architecture that has been defined for SCN signaling The framework architecture that has been defined for SCN signaling
transport over IP [5] uses multiple components, including a signaling transport over IP [6] uses multiple components, including a signaling
common transport protocol and an adaptation module to support the common transport protocol and an adaptation module to support the
services expected by a particular SCN signaling protocol from its services expected by a particular SCN signaling protocol from its
underlying protocol layer. underlying protocol layer.
Within this framework architecture, this document defines a SCN Within this framework architecture, this document defines a SCN
adaptation module that is suitable for the transport of SS7 MTP2 User adaptation module that is suitable for the transport of SS7 MTP2 User
messages. The only SS7 MTP2 User is MTP3. The M2UA uses the services messages. The only SS7 MTP2 User is MTP3. The M2UA uses the services
of the Simple Common Transport protocol [6] as the underlying reliable of the Stream Control Transmission Protocol [5] as the underlying
signaling common transport protocol. reliable signaling common transport protocol.
In a Signaling Gateway, it is expected that the SS7 MTP2-User signaling In a Signaling Gateway, it is expected that the SS7 MTP2-User signaling
is transmitted and received from the PSTN over a standard SS7 network is transmitted and received from the PSTN over a standard SS7 network
interface, using the SS7 Message Transfer Part Level 1 and Level 2 [3,4] interface, using the SS7 Message Transfer Part Level 1 and Level 2 [3,4]
to provide reliable transport of the MTP3-User signaling messages to and to provide reliable transport of the MTP3-User signaling messages to and
from an SS7 Signaling End Point (SEP) or Signaling Transfer Point (STP). from an SS7 Signaling End Point (SEP) or Signaling Transfer Point (STP).
The SG then provides a functional inter-working of transport functions The SG then provides a functional inter-working of transport functions
with the IP transport, in order to transfer the MTP2-User signaling with the IP transport, in order to transfer the MTP2-User signaling
messages to and from an Application Server Process where the peer MTP2- messages to and from an Application Server Process where the peer MTP2-
User protocol layer exists. User protocol layer exists.
skipping to change at page 5, line 25 skipping to change at page 5, line 25
|MTP | |MTP |M2UA| |M2UA| |MTP | |MTP |M2UA| |M2UA|
| | | +----+ +----+ | | | +----+ +----+
|L2 | |L2 |SCTP| |SCTP| |L2 | |L2 |SCTP| |SCTP|
|L1 | |L1 +----+ +----+ |L1 | |L1 +----+ +----+
| | | |IP | |IP | | | | |IP | |IP |
+----+ +---------+ +----+ +----+ +---------+ +----+
NIF - Nodal Interworking Function NIF - Nodal Interworking Function
SEP - SS7 Signaling Endpoint SEP - SS7 Signaling Endpoint
IP - Internet Protocol IP - Internet Protocol
SCTP - Simple Control Transmission Protocol SCTP - Stream Control Transmission Protocol
(Refer to Reference [5]) (Refer to Reference [5])
Figure 1 M2UA in the SG to MGC Application Figure 1 M2UA in the SG to MGC Application
Note: STPs may be present in the SS7 path between the SEP and the SG. Note: STPs MAY be present in the SS7 path between the SEP and the SG.
1.3.2 Signaling Network Architecture It is recommended that the M2UA use the services of the Stream
Control Transmission Protocol (SCTP) as the underlying reliable
common signaling transport protocol. The use of SCTP provides
the following features:
- explicit packet-oriented delivery (not stream-oriented)
- sequenced delivery of user messages within multiple streams,
with an option for order-of-arrival delivery of individual
user messages,
- optional multiplexing of user messages into SCTP datagrams,
- network-level fault tolerance through support of multi-homing
at either or both ends of an association,
- resistance to flooding and masquerade attacks, and
- data segmentation to conform to discovered path MTU size
There are scenarios without redundancy requirements and
scenarios in which redundancy is supported below the transport
layer. In these cases, the SCTP functions above MAY NOT be a
requirement and TCP can be used as the underlying common
transport protocol.
1.3.2 Support for the management of SCTP associations between the SG
and ASPs
The M2UA layer at the SG maintains the availability state of all
dynamically registered remote ASPs, in order to manage the SCTP
Associations and the traffic between the SG and ASPs. As well, the
active/inactive state of remote ASP(s) are also maintained. Active
ASPs are those currently receiving traffic from the SG.
The M2UA layer MAY be instructed by local management to establish an
SCTP association to a peer M2UA node. This can be achieved using the M-
SCTP ESTABLISH primitive to request, indicate and confirm the
establishment of an SCTP association with a peer M2UA node.
The M2UA layer MAY also need to inform local management of the status of
the underlying SCTP associations using the M-SCTP STATUS request and
indication primitive. For example, the M2UA MAY inform local management
of the reason for the release of an SCTP association, determined either
locally within the M2UA layer or by a primitive from the SCTP.
1.3.3 Signaling Network Architecture
A Signaling Gateway will support the transport of MTP2-User signaling A Signaling Gateway will support the transport of MTP2-User signaling
traffic received from the SS7 network to one or more distributed ASPs traffic received from the SS7 network to one or more distributed ASPs
(e.g., MGCs). Clearly, the M2UA protocol description cannot in itself (e.g., MGCs). Clearly, the M2UA protocol description cannot in itself
meet any performance and reliability requirements for such transport. meet any performance and reliability requirements for such transport.
A physical network architecture is required, with data on the A physical network architecture is required, with data on the
availability and transfer performance of the physical nodes involved in availability and transfer performance of the physical nodes involved in
any particular exchange of information. However, the M2UA protocol must any particular exchange of information. However, the M2UA protocol MUST
be flexible enough allow its operation and management in a variety of be flexible enough allow its operation and management in a variety of
physical configurations that will enable Network Operators to meet physical configurations that will enable Network Operators to meet
their performance and reliability requirements. their performance and reliability requirements.
To meet the stringent SS7 signaling reliability and performance To meet the stringent SS7 signaling reliability and performance
requirements for carrier grade networks, these Network Operators should requirements for carrier grade networks, these Network Operators SHOULD
ensure that there is no single point of failure provisioned in the end- ensure that there is no single point of failure provisioned in the end-
to-end network architecture between an SS7 node and an IP ASP. Depending to-end network architecture between an SS7 node and an IP ASP.
of course on the reliability of the SG and ASP functional elements, this
can typically be met by the spreading links in a linkset across SGs, the Depending of course on the reliability of the SG and ASP functional
provision of redundant QOS-bounded IP network paths for SCTP Associations elements, this can typically be met by the spreading links in a linkset
between SCTP End Points, and redundant Hosts. The distribution of ASPs across SGs, the provision of redundant QOS-bounded IP network paths for
within the available Hosts is also important. For a particular SCTP Associations between SCTP End Points, and redundant Hosts. The
Application Server, the related ASPs should be distributed over at least distribution of ASPs within the available Hosts is also important. For a
two Hosts. particular Application Server, the related ASPs SHOULD be distributed over
at least two Hosts.
An example physical network architecture relevant to carrier-grade An example physical network architecture relevant to carrier-grade
operation in the IP network domain is shown in Figure 2 below: operation in the IP network domain is shown in Figure 2 below:
******** ************** ******** **************
* *_________________________________________* ******** * Host1 * *_________________________________________* ******** * Host1
* * _________* * ASP1 * * * * _________* * ASP1 * *
* SG1 * SCTP Associations | * ******** * * SG1 * SCTP Associations | * ******** *
* *_______________________ | * * * *_______________________ | * *
******** | | ************** ******** | | **************
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|____________________________* * ASP1 * * |____________________________* * ASP1 * *
* ******** * * ******** *
* * * *
************** **************
. .
. .
. .
Figure 2 - Physical Model Example Figure 2 - Physical Model Example
For carrier grade networks, Operators should ensure that under failure For carrier grade networks, Operators SHOULD ensure that under failure
or isolation of a particular ASP, stable calls or transactions are not or isolation of a particular ASP, stable calls or transactions are not
lost. This implies that ASPs need, in some cases, to share the call/- lost. This implies that ASPs need, in some cases, to share the call/-
transaction state or be able to pass the call/transaction state between transaction state or be able to pass the call/transaction state between
each other. Also, in the case of ASPs performing call processing, each other. Also, in the case of ASPs performing call processing,
coordination may be required with the related Media Gateway to transfer coordination MAY be required with the related Media Gateway to transfer
the MGC control for a particular trunk termination. However, this the MGC control for a particular trunk termination. However, this
sharing or communication is outside the scope of this document. sharing or communication is outside the scope of this document.
1.3.4 ASP Fail-over Model and Terminology 1.3.4 ASP Fail-over Model and Terminology
The M2UA supports ASP fail-over functions in order to support a high The M2UA layer supports ASP fail-over functions in order to support a
availability of call and transaction processing capability. All MTP2- high availability of call and transaction processing capability. All
User messages incoming to an SG from the SS7 network are assigned to a MTP2-User messages incoming to an SG from the SS7 network are assigned
unique Application Server, based on the Interface Identifier of the to a unique Application Server, based on the Interface Identifier of
message. the message.
The Application Server is in practical terms a list of all ASPs currently The Application Server is in practical terms a list of all ASPs currently
registered to process MTP2-User messages from certain Interface registered to process MTP2-User messages from certain Interface
Identifiers. One or more ASPs in the list are normally active (i.e., Identifiers. One or more ASPs in the list are normally active (i.e.,
handling traffic) while any others may be unavailable or inactive, to be handling traffic) while any others MAY be unavailable or inactive, to be
possibly used in the event of failure or unavailability of the active possibly used in the event of failure or unavailability of the active
ASP(s). ASP(s).
The fail-over model supports an ˘n+k÷ redundancy model, where ˘n÷ ASPs The fail-over model supports an n+k redundancy model, where n ASPs
is the minimum number of redundant ASPs required to handle traffic and is the minimum number of redundant ASPs required to handle traffic and
˘k÷ ASPs are available to take over for a failed or unavailable ASP. k ASPs are available to take over for a failed or unavailable ASP.
Note that ˘1+1÷ active/standby redundancy is a subset of this model. Note that 1+1 active/standby redundancy is a subset of this model.
A simplex ˘1+0÷ model is also supported as a subset, with no ASP A simplex 1+0 model is also supported as a subset, with no ASP
redundancy. redundancy.
To avoid a single point of failure, it is recommended that a minimum of To avoid a single point of failure, it is recommended that a minimum of
two ASPs be in the list, resident in separate hosts and therefore two ASPs be in the list, resident in separate hosts and therefore
available over different SCTP Associations. For example, in the available over different SCTP Associations. For example, in the
network shown in Figure 1, all messages to DPC x could be sent to ASP1 network shown in Figure 2, all messages to DPC x could be sent to ASP1
in Host1 or ASP1 in Host2. The AS list at SG1 might look like this: in Host1 or ASP1 in Host2. The AS list at SG1 might look like this:
Interface Identiers - Application Server #1 Interface Identiers - Application Server #1
ASP1/Host1 - State=Up, Active ASP1/Host1 - State = Active
ASP1/Host2 - State=Up, Inactive ASP1/Host2 - State = Inactive
In this ˘1+1÷ redundancy case, ASP1 in Host1 would be sent any incoming In this 1+1 redundancy case, ASP1 in Host1 would be sent any incoming
message for the Interface Identifiers registered. ASP1 in Host2 would message for the Interface Identifiers registered. ASP1 in Host2 would
normally be brought to the active state upon failure of, or loss of normally be brought to the active state upon failure of, or loss of
connectivity to, ASP1/Host1. In this example, both ASPs are Up, meaning connectivity to, ASP1/Host1. In this example, both ASPs are Inactive
that the related SCTP association and far-end M2UA peer is ready. or Active, meaning that the related SCTP association and far-end M2UA
peer is ready.
The AS List at SG1 might also be set up in loadshare mode:
Interface Identifiers - Application Server #1
ASP1/Host1 - State = Up, Active
ASP1/Host2 - State = Up, Active
In this case, both the ASPs would be sent a portion of the traffic.
In the process of fail-over or fail-back, it is recommended that in the In the process of fail-over or fail-back, it is recommended that in the
case of ASPs supporting call processing, stable calls do not fail. It case of ASPs supporting call processing, stable calls do not get released.
is possible that calls in ˘transition÷ may fail, although measures of It is possible that calls in transition MAY fail, although measures of
communication between the ASPs involved can be used to mitigate this. communication between the ASPs involved can be used to mitigate this.
For example, the two ASPs may share call state via shared memory, or may For example, the two ASPs MAY share call state via shared memory, or MAY
use an ASP to ASP protocol to pass call state information. use an ASP to ASP protocol to pass call state information. The ASP to ASP
protocol is outside the scope of this document.
1.3.5 Client/Server Model 1.3.5 Client/Server Model
It is recommended that the SG take on the role of server while the It is recommended that the SG and ASP be able to support both client
ASP is the client. ASPs should initiate the SCTP association to the and server operation. The peer endpoints using M2UA SHOULD be
SG. configured so that one always takes on the role of client and the
other the role of server for initiating SCTP associations. The
default orientation would be for the SG to take on the role of server
while the ASP is the client. In this case, ASPs SHOULD initiate the
SCTP association to the SG.
The SCTP (and UDP/TCP) Registered User Port Number Assignment for M2UA The SCTP (and UDP/TCP) Registered User Port Number Assignment for M2UA
is 2904. is 2904.
1.4 Services Provided by the M2UA Adaptation Layer 1.4 Services Provided by the M2UA Adaptation Layer
The SS7 MTP3/MTP2(MTP2-User) interface is retained at the termination The SS7 MTP3/MTP2(MTP2-User) interface is retained at the termination
point in the IP network, so that the M2UA protocol layer is required to point in the IP network, so that the M2UA protocol layer is required to
provide the equivalent set of services to its users as provided by the provide the equivalent set of services to its users as provided by the
MTP Level 2 to MTP Level 3. MTP Level 2 to MTP Level 3.
skipping to change at page 8, line 38 skipping to change at page 8, line 38
Data Retrieval Data Retrieval
Provides a mechanism to perform SS7 link changeover procedure in Provides a mechanism to perform SS7 link changeover procedure in
the case of a SS7 link failure. the case of a SS7 link failure.
1.4.2 Support for communication between Layer Management modules 1.4.2 Support for communication between Layer Management modules
on SG and MGC on SG and MGC
It is envisioned that the M2UA layer needs to provide some messages that It is envisioned that the M2UA layer needs to provide some messages that
will facilitate communication between Layer Management modules on the SG will facilitate communication between Layer Management modules on the SG
and MGC. and MGC. These primitives are shown below:
To facilitate reporting of errors that arise because of backhauling MTP To facilitate reporting of errors that arise because of backhauling MTP
Level 3 scenario, the following primitive is defined: Level 3 scenario, the following primitive is defined:
M-ERROR M-ERROR
The M-ERROR message is used to indicate an error with a received The M-ERROR message is used to indicate an error with a received
M2UA message (e.g., interface identifier value is not known to the SG). M2UA message (e.g., interface identifier value is not known to the SG).
1.4.3 Support for management of active associations between SG and MGC 1.4.3 Support for management of active associations between SG and MGC
The M2UA layer on the SG keeps the state of various ASPs it is associated The M2UA layer on the SG keeps the state of various ASPs it is associated
with. A set of primitives between M2UA layer and the Layer Management with. A set of primitives between M2UA layer and the Layer Management
are defined below to help the Layer Management manage the association(s) are defined below to help the Layer Management manage the association(s)
between the SG and the MGC. between the SG and the MGC. The M2UA layer can be instructed
by the Layer Management to establish a SCTP association to a peer M2UA
node. This procedure can be achieved using the M-SCTP ESTABLISH
primitive.
M-SCTP ESTABLISH M-SCTP ESTABLISH
The M-SCTP ESTABLISH primitive is used to request, indicate and confirm The M-SCTP ESTABLISH primitive is used to request, indicate and confirm
the establishment of SCTP association to a peer M2UA node. the establishment of a SCTP association to a peer M2UA node.
The M2UA layer may also need to inform the status of the SCTP M-SCTP RELEASE
The M-SCTP RELEASE primitives are used to request, indicate, and
confirm the release of a SCTP association to a peer M2UA node.
The M2UA layer MAY also need to inform the status of the SCTP
associations to the Layer Management. This can be achieved using
the M-SCTP STATUS primitive.
The M2UA layer MAY also need to inform the status of the SCTP
association(s) to the Layer Management. This can be achieved using association(s) to the Layer Management. This can be achieved using
the following primitive. the following primitive.
M-SCTP STATUS M-SCTP STATUS
The M-SCTP STATUS primitive is used to request and indicate the status The M-SCTP STATUS primitive is used to request and indicate the status
of underlying SCTP association(s). of underlying SCTP association(s).
The Layer Management may need to inform the M2UA layer of a user status The Layer Management MAY need to inform the M2UA layer of an AS/ASP
(i.e., failure, active, etc.), so that messages can be exchanged between status (i.e., failure, active, etc.), so that messages can be exchanged
M2UA layer peers to stop traffic to the local M2UA user. This can be between M2UA layer peers to stop traffic to the local M2UA user. This
achieved using the following primitive. can be achieved using the following primitive.
M-ASP STATUS M-ASP STATUS
The M-ASP STATUS primitive is used by the Layer Management to indicate The ASP status is stored inside M2UA layer on both the SG and MGC
the status of the local M2UA user to the M2UA layer. sides. The M-ASP STATUS primitive can be used by Layer Management to
request the status of the Application Server Process from the M2UA
layer. This primitive can also be used to indicate the status of the
Application Server Process.
M-ASP MODIFY
The M-ASP MODIFY primitive can be used by Layer Management to modify
the status of the Application Server Process. In other words, the
Layer Management on the ASP side uses this primitive to initiate
the ASPM procedures.
M-AS STATUS
The M-AS STATUS primitive can be used by Layer Management to request
the status of the Application Server. This primitive can also be
used to indicate the status of the Application Server.
1.5 Functions Provided by the M2UA Layer 1.5 Functions Provided by the M2UA Layer
1.5.1 Mapping 1.5.1 Mapping
The M2UA layer must maintain a map of a Interface ID to a physical The M2UA layer MUST maintain a map of a Interface ID to a physical
interface on the Signaling Gateway. A physical interface would be a interface on the Signaling Gateway. A physical interface would be a
V.35 line, T1 line/timeslot, E1 line/timeslot, etc. The M2UA layer V.35 line, T1 line/timeslot, E1 line/timeslot, etc. The M2UA layer
must also maintain a map of Interface Identifier to SCTP association MUST also maintain a map of Interface Identifier to SCTP association
and to the related stream within the association. and to the related stream within the association.
1.5.2 Flow Control / Congestion The SG maps an Interface Identifier to an SCTP association/stream
only when an ASP sends an ASP Active message for a particular Interface
Identifier. It MUST be noted, however, that this mapping is dynamic
and could change at any time due to a change of ASP state. This mapping
could even temporarily be invalid, for example during failover of one
ASP to another. Therefore, the SG MUST maintain the states of AS/ASP
and reference them during the routing of an messages to an AS/ASP.
It is possible for the M2UA layer to be informed of IP network congestion An example of the logical view of relationship between SS7 link,
by means of an implementation-dependent function (i.e. an indication Interface Identifier, AS and ASP in the SG is shown below:
from the SCTP). If the M2UA layer receives this indication, the action(s)
taken are implementation dependent. /---------------------------------------------------+
/ /------------------------------------------------|--+
/ / v |
/ / +----+ act+-----+ +-------+ -+--+-|+--+-
SS7 link1-------->|IID |-+ +-->| ASP |--->| Assoc | v
/ +----+ | +----+ | +-----+ +-------+ -+--+--+--+-
/ +->| AS |--+ Streams
/ +----+ | +----+ stb+-----+
SS7 link2-------->|IID |-+ | ASP |
+----+ +-----+
where IID = Interface Identifier
1.5.2 Status of ASPs
The M2UA layer on the SG MUST maintain the state of the ASPs it is
supporting. The state of an ASP changes because of reception of
peer-to-peer messages (ASPM messages as described in Section 3.3.2)
or reception of indications from the local SCTP association. ASP
state transition procedures are described in Section 4.3.1.
At a SG, an Application Server list MAY contain active and inactive
ASPs to support ASP fail-over procedures. When, for example, both
a primary and a back-up ASP are available, M2UA peer protocol is
required to control which ASP is currently active. The ordered
list of ASPs within a logical Application Server is kept updated in
the SG to reflect the active Application Server Process(es).
Also the M2UA layer MAY need to inform the local management of the
change in status of an ASP or AS. This can be achieved using the M-ASP
STATUS or M-AS STATUS primitives.
1.5.3 SCTP Stream Management 1.5.3 SCTP Stream Management
SCTP allows user specified number of streams to be opened during the SCTP allows user specified number of streams to be opened during the
initialization. It is the responsibility of the M2UA layer to ensure initialization. It is the responsibility of the M2UA layer to ensure
proper management of these streams. SCTP streams provide a means for proper management of these streams. Because of the unidirectional
avoiding head of line blocking. For that reason, a stream should be used nature of streams, M2UA layers are not aware of the stream information
per SS7 signaling link terminated by the Signaling Gateway. The SS7 from the peer M2UA layers. Instead, the Interface Identifier is
signaling link can be identified by the optional Interface Identifier in the M2UA message header.
in the M2UA specific message header (refer to Section 2.2).
The use of SCTP streams within M2UA is recommended in order to minimize
transmission and buffering delay, therefore improving the overall
performance and reliability of the signaling elements. It is
recommended that a separate SCTP stream is used for each SS7 link.
1.5.4 Seamless SS7 Network Management Interworking 1.5.4 Seamless SS7 Network Management Interworking
If the SG loses the SCTP association to the MGC, it should follow The M2UA layer on the SG SHOULD pass an indication of unavailability of
MTP 2 processor outage procedures [2]. the M2UA-User (MTP3) to the local Layer Management, if the currently
active ASP moves from the ACTIVE state. If the AS moves to the DOWN
state while SS7 links are in-service, the SG SHOULD follow the MTP 2
processor outage procedures [2].
1.5.5 Active Association Control 1.5.5 Flow Control / Congestion
At an SG, an Application Server list may contain active and inactive It is possible for the M2UA layer to be informed of IP network congestion
ASPs to support ASP loads-haring and fail-over procedures. When, for by means of an implementation-dependent function (i.e. an indication
example, both a primary and a back-up ASP are available, M2UA peer from the SCTP). If the M2UA layer receives this indication, the action(s)
protocol is required to control which ASP is currently active. The taken are implementation dependent.
ordered list of ASPs within a logical Application Server is kept
updated in the SG to reflect the active Application Server Process(es).
1.6 Definition of the M2UA Boundaries 1.6 Definition of the M2UA Boundaries
1.6.1 Definition of the M2UA / MTP Level 3 boundary 1.6.1 Definition of the M2UA / MTP Level 3 boundary
DATA DATA
ESTABLISH ESTABLISH
RELEASE RELEASE
STATE STATE
STATUS STATUS
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RELEASE RELEASE
STATE STATE
STATUS STATUS
RETRIEVAL RETRIEVAL
DATA RETRIEVAL DATA RETRIEVAL
DATA RETRIEVAL COMPLETE DATA RETRIEVAL COMPLETE
1.6.3 Definition of the Lower Layer Boundary between M2UA and SCTP 1.6.3 Definition of the Lower Layer Boundary between M2UA and SCTP
The upper layer and layer management primitives provided by SCTP are The upper layer and layer management primitives provided by SCTP are
provided in Reference [6] Section 9. provided in Reference [5] Section 9.
1.6.4 Definition of Layer Management / M2UA Boundary 1.6.4 Definition of Layer Management / M2UA Boundary
M-ERROR M-SCTP ESTABLISH request
M-SCTP ESTABLISH Direction: LM -> M2UA
M-SCTP STATUS Purpose: LM requests ASP to establish an SCTP association with an SG.
M-ASP STATUS
M-STCP ESTABLISH confirm
Direction: M2UA -> LM
Purpose: ASP confirms to LM that it has established an SCTP
association with an SG.
M-SCTP ESTABLISH indication
Direction: M2UA -> LM
Purpose: SG informs LM that an ASP has established an SCTP
association.
M-SCTP RELEASE request
Direction: LM -> M2UA
Purpose: LM requests ASP to release an SCTP association with SG.
M-SCTP RELEASE confirm
Direction: M2UA -> LM
Purpose: ASP confirms to LM that it has released SCTP association
with SG.
M-SCTP RELEASE indication
Direction: M2UA -> LM
Purpose: SG or IPSP informs LM that ASP has released an SCTP
association.
M-SCTP STATUS request
Direction: LM -> M2UA
Purpose: LM requests M2UA to report status of SCTP association.
M-SCTP STATUS indication
Direction: M2UA -> LM
Purpose: M2UA reports status of SCTP association.
M-ASP STATUS request
Direction: LM -> M2UA
Purpose: LM requests SG to report status of remote ASP.
M-ASP STATUS indication
Direction: M2UA -> LM
Purpose: SG reports status of remote ASP.
M-AS-STATUS request
Direction: LM -> M2UA
Purpose: LM requests SG to report status of AS.
M-AS-STATUS indication
Direction: M2UA -> LM
Purpose: SG reports status of AS.
M-NOTIFY indication
Direction: M2UA -> LM
Purpose: ASP reports that it has received a NOTIFY message
from its peer.
M-ERROR indication
Direction: M2UA -> LM
Purpose: ASP or SG reports that it has received an ERROR
message from its peer.
M-ASP-UP request
Direction: LM -> M2UA
Purpose: LM requests ASP to start its operation and send an ASP UP
message to the SG.
M-ASP-UP confirm
Direction: M2UA -> LM
Purpose: ASP reports that is has received an ASP UP Acknowledgement
message from the SG.
M-ASP-DOWN request
Direction: LM -> M2UA
Purpose: LM requests ASP to stop its operation and send an ASP DOWN
message to the SG.
M-ASP-DOWN confirm
Direction: M2UA -> LM
Purpose: ASP reports that is has received an ASP DOWN Acknowledgement
message from the SG.
M-ASP-ACTIVE request
Direction: LM -> M2UA
Purpose: LM requests ASP to send an ASP ACTIVE message to the SG.
M-ASP-ACTIVE confirm
Direction: M2UA -> LM
Purpose: ASP reports that is has received an ASP ACTIVE Acknowledgement
message from the SG.
M-ASP-INACTIVE request
Direction: LM -> M2UA
Purpose: LM requests ASP to send an ASP INACTIVE message to the SG.
M-ASP-INACTIVE confirm
Direction: M2UA -> LM
Purpose: ASP reports that is has received an ASP INACTIVE Acknowledgement
message from the SG.
2.0 Conventions 2.0 Conventions
The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD
NOT, RECOMMENDED, NOT RECOMMENDED, MAY, and OPTIONAL, when they appear NOT, RECOMMENDED, NOT RECOMMENDED, MAY, and OPTIONAL, when they appear
in this document, are to be interpreted as described in [RFC2119]. in this document, are to be interpreted as described in [RFC2119].
3.0 Protocol Elements 3.0 Protocol Elements
This section describes the format of various messages used in this This section describes the format of various messages used in this
protocol. protocol.
3.1 Common Message Header 3.1 Common Message Header
The protocol messages for MTP2-User Adaptation require a message The protocol messages for MTP2-User Adaptation require a message
structure which contains a version, message type, message length, and structure which contains a version, message class, message type, message
message contents. This message header is common among all signaling length, and message contents. This message header is common among all
protocol adaptation layers: signaling protocol adaptation layers:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Spare | Message Type | | Version | Spare | Message Class | Message Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Length | | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3 Common Message Header Figure 3 Common Message Header
All fields in an M2UA message MUST be transmitted in the network byte All fields in an M2UA message MUST be transmitted in the network byte
order, unless otherwise stated. order, unless otherwise stated.
3.1.1 Version 3.1.1 Version
The version field (vers) contains the version of the M2UA adapation The version field (vers) contains the version of the M2UA adapation
layer. The supported versions are: layer. The supported versions are:
Release 1.0 0x1 Value Version
----- -------
1 Release 1.0
3.1.2 Message Type 3.1.2 Message Type
The valid message types are defined in Section 3.2.2 and the message The following List contains the valid Message Classes:
contents are described in Section 3.3. Each message can contain
parameters. Message Class: 8 bits (unsigned integer)
0 Management (MGMT) Message
1 Reserved
2 Reserved
3 ASP State Maintenance (ASPSM) Messages
4 ASP Traffic Maintenance (ASPTM) Messages
5 Reserved
6 MTP2 User Adaptation (MAUP) Messages
Messages
7 to 255 Reserved
The following list contains the message types for the defined messages. The following list contains the message types for the defined messages.
MTP2 User Adaptatation (MAUP) Messages MTP2 User Adaptatation (MAUP) Messages
Data 0x0601 0 Reserved
Establish Request 0x0602 1 Data
Establish Confirm 0x0603 2 Establish Request
Release Request 0x0604 3 Establish Confirm
Release Confirm 0x0605 4 Release Request
Release Indication 0x0606 5 Release Confirm
State Request 0x0607 6 Release Indication
State Confirm 0x0608 7 State Request
State Indication 0x0609 8 State Confirm
Data Retrieval Request 0x060a 9 State Indication
Data Retrieval Confirm 0x060b 10 Data Retrieval Request
Data Retrieval Indication 0x060c 11 Data Retrieval Confirm
Data Retrieval Complete Indication 0x060d 12 Data Retrieval Indication
13 Data Retrieval Complete Indication
14 to 255 Reserved for MAUP Messages
Application Server Process State Maintenance (ASPSM) messages
Application Server Process Maintenance (ASPM) Messages 0 Reserved
1 ASP Up (UP)
2 ASP Down (DOWN)
3 Heartbeat (BEAT)
4 ASP Up Ack (UP ACK)
5 ASP Down Ack (DOWN ACK)
6 Heatbeat Ack (BEAT ACK)
7 to 255 Reserved for ASPSM Messages
Application Server Process Traffic Maintenance (ASTM) messages
0 Reserved
1 ASP Active (ACTIVE)
2 ASP Inactive (INACTIVE)
3 ASP Active Ack (ACTIVE ACK)
4 ASP Inactive Ack (INACTIVE ACK)
5 to 255 Reserved for ASPTM Messages
ASP Up 0x0301
ASP Down 0x0302
Heartbeat 0x0303
ASP Up Ack 0x0304
ASP Down Ack 0x0305
ASP Active 0x0401
ASP Inactive 0x0402
ASP Active 0x0403
ASP Inactive 0x0404
Management (MGMT) Messages Management (MGMT) Messages
Error 0x0000 0 Error (ERR)
Notify 0x0001 1 Notify (NTFY)
2 to 255 Reserved for Management Messages
3.1.3 Message Length 3.1.3 Reserved
The Message length defines the length of the message in octets, not The Reserved field is 8-bits. It SHOULD be set to all '0's and
ignored by the receiver.
3.1.4 Message Length
The Message length defines the length of the message in octets,
including the header. including the header.
3.1.4 Variable-Length Parameter Format 3.1.5 Variable-Length Parameter Format
IUA messages consist of a Common Header followed by zero or more M2UA messages consist of a Common Header followed by zero or more
variable-length parameters, as defined by the message type. The variable-length parameters, as defined by the message type. The
variable-length parameters contained in a message are defined in a variable-length parameters contained in a message are defined in a
Tag-Length-Value format as shown below. Tag-Length-Value format as shown below.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Parameter Tag | Parameter Length | | Parameter Tag | Parameter Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ \ \ \
skipping to change at page 12, line 44 skipping to change at page 12, line 70
a value of 0 to 65534. a value of 0 to 65534.
The value of 65535 is reserved for IETF-defined extensions. Values The value of 65535 is reserved for IETF-defined extensions. Values
other than those defined in specific parameter description are reserved other than those defined in specific parameter description are reserved
for use by the IETF. for use by the IETF.
Parameter Length: 16 bits (unsigned integer) Parameter Length: 16 bits (unsigned integer)
The Parameter Length field contains the size of the parameter in bytes, The Parameter Length field contains the size of the parameter in bytes,
including the Parameter Tag, Parameter Length, and Parameter Value including the Parameter Tag, Parameter Length, and Parameter Value
fields. Thus, a parameter with a zero-length Parameter Value field fields. The Parameter Length does not include any padding bytes.
would have a Length field of 4. The Parameter Length does not include
any padding bytes.
Parameter Value: variable-length. Parameter Value: variable-length.
The Parameter Value field contains the actual information to be The Parameter Value field contains the actual information to be
transferred in the parameter. transferred in the parameter.
The total length of a parameter (including Tag, Parameter Length and Value The total length of a parameter (including Tag, Parameter Length and Value
fields) MUST be a multiple of 4 bytes. If the length of the parameter is fields) MUST be a multiple of 4 bytes. If the length of the parameter is
not a multiple of 4 bytes, the sender pads the Parameter at the end (i.e., not a multiple of 4 bytes, the sender pads the Parameter at the end (i.e.,
after the Parameter Value field) with all zero bytes. The length of the after the Parameter Value field) with all zero bytes. The length of the
padding is NOT included in the parameter length field. A sender should padding is NOT included in the parameter length field. A sender SHOULD
NEVER pad with more than 3 bytes. The receiver MUST ignore the padding NOT pad with more than 3 bytes. The receiver MUST ignore the padding
bytes. bytes.
3.2 M2UA Message Header 3.2 M2UA Message Header
In addition to the common message header, there will be a M2UA specific In addition to the common message header, there will be a M2UA specific
message header. The M2UA specific message header will immediately message header. The M2UA specific message header will immediately
follow the common message header, but will only be used with MAUP follow the common message header, but will only be used with MAUP
messages. messages.
This message header will contain the Interface Identifier. The This message header will contain the Interface Identifier. The
Interface Identifier identifies the physical interface at the SG for Interface Identifier identifies the physical interface at the SG for
which the signaling messages are sent/received. The format of the which the signaling messages are sent/received. The format of the
Interface Identifier parameter is an integer, the values of which are Interface Identifier parameter can be text or integer, the values of which
assigned according to network operator policy. The values used are of are assigned according to network operator policy. The values used are of
local significance only, coordinated between the SG and ASP. local significance only, coordinated between the SG and ASP.
The integer formatted Interface Identifier MUST be supported. The
text formatted Interface Identifier MAY optionally be supported.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x1) | Length=4 | | Tag (0x1) | Length=8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier | | Interface Identifier (integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4 M2UA Message Header Figure 4 M2UA Message Header (Integer-based Interface Identifier)
The Tag value for Interface Identifier is 0x1. The length is always The Tag value for Integer-based Interface Identifier is 0x1. The length is
set to a value of 8. always set to a value of 8.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x3) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier (text) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5 M2UA Message Header (Text-based Interface Identifier)
The Tag value for the Text-based Interface Identifier is 0x3. The
length is variable.
3.3 M2UA Messages 3.3 M2UA Messages
The following section defines the messages and parameter contents. The The following section defines the messages and parameter contents. The
M2UA messages will use the common message header (Figure 3) and the M2UA messages will use the common message header (Figure 3) and the
M2UA message header (Figure 4). M2UA message header (Figure 4).
3.3.1 MTP2 User Adaptation Messages 3.3.1 MTP2 User Adaptation Messages
3.3.1.1 Data 3.3.1.1 Data
skipping to change at page 13, line 16 skipping to change at page 13, line 16
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Protocol Data | | Protocol Data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Protocol Data field contains the MTP2-User application message in The Protocol Data field contains the MTP2-User application message in
network byte order. network byte order starting with the Signaling Information Octet (SIO).
3.3.1.2 Establish (Request, Confirmation) 3.3.1.2 Establish (Request, Confirmation)
The Establish Request message is used to establish the link or to The Establish Request message is used to establish the link or to
indicate that the channel has been established. Note that the gateway indicate that the channel has been established. The MGC controls the state of the
may already have the SS7 link established at its layer. If so, upon SS7 link. When the MGC desires the SS7 link to be in-service,
it will send the Establish Request message. Note that the gateway
MAY already have the SS7 link established at its layer. If so, upon
receipt of an Establish Request, the gateway takes no action except to receipt of an Establish Request, the gateway takes no action except to
send an Establish Confirm. send an Establish Confirm.
When the MGC sends an M2UA Establish Request message, the MGC MAY
start a timer. This timer would be stopped upon receipt of an M2UA
Establish Confirm. If the timer expires, the MGC would re-send the
M2UA Establish Request message and restart the timer. In other words,
the MGC MAY continue to request the establishment of the data link
on periodic basis until the desired state is achieved or take some
other action (notify the Management Layer).
The mode (Normal of Emergency) for bringing the link in service is The mode (Normal of Emergency) for bringing the link in service is
defaulted to Normal. The State Request (described in Section 3.3.1.4 defaulted to Normal. The State Request (described in Section 3.3.1.4
below) can be used to change the mode to Emergency. below) can be used to change the mode to Emergency.
3.3.1.3 Release (Request, Indication, Confirmation) 3.3.1.3 Release (Request, Indication, Confirmation)
This Release Request message is used to release the channel. The This Release Request message is used to release the channel. The
Release Confirm and Indication messages are used to indicate that the Release Confirm and Indication messages are used to indicate that the
channel has been released. channel has been released.
skipping to change at page 13, line 56 skipping to change at page 13, line 66
RELEASE_PHYS 0x1 Physical layer alarm generated release RELEASE_PHYS 0x1 Physical layer alarm generated release
RELEASE_SIOS 0x2 Receipt of SIOS RELEASE_SIOS 0x2 Receipt of SIOS
RELEASE_T6 0x3 Release due to expiration of Timer T6 RELEASE_T6 0x3 Release due to expiration of Timer T6
RELEASE_T7 0x4 Release due to expiration of Timer T7 RELEASE_T7 0x4 Release due to expiration of Timer T7
RELEASE_BSN 0x5 Release due to invalid BSN (2 of 3) RELEASE_BSN 0x5 Release due to invalid BSN (2 of 3)
RELEASE_FIB 0x6 Release due to invalid FIB (2 of 3) RELEASE_FIB 0x6 Release due to invalid FIB (2 of 3)
RELEASE_SUERM 0x7 Release due to failure reported by SUERM RELEASE_SUERM 0x7 Release due to failure reported by SUERM
RELEASE_IAC 0x8 Release due to initial alignment failed RELEASE_IAC 0x8 Release due to initial alignment failed
RELEASE_OTHER 0x9 Other reason SS7 link out-of-service RELEASE_OTHER 0x9 Other reason SS7 link out-of-service
For the Release Request, the only valid Reason is RELEASE_MGMT. For
Release Confirm, the Reason field would also be RELEASE_MGMT (a
reflection of Release Request). The other valid values for Reason
would be used for Release Indication.
3.3.1.4 State (Request, Confirm) 3.3.1.4 State (Request, Confirm)
The State Request message can be sent from a MGC to cause an action The State Request message can be sent from a MGC to cause an action
on a particular SS7 link supported by the Signaling Gateway. The on a particular SS7 link supported by the Signaling Gateway. The
gateway sends a State Confirm to the MGC if the action has been success- gateway sends a State Confirm to the MGC if the action has been success-
fully completed. The State Confirm reflects that state value received fully completed. The State Confirm reflects that state value received
in the State Request message. in the State Request message.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
skipping to change at page 15, line 21 skipping to change at page 15, line 21
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The valid values for Action are shown in the following table. The valid values for Action are shown in the following table.
Define Value Description Define Value Description
ACTION_RTRV_BSN 0x1 Retrieve the backward sequence number ACTION_RTRV_BSN 0x1 Retrieve the backward sequence number
ACTION_RTRV_MSGS 0x2 Retrieve the PDUs from the retransmit ACTION_RTRV_MSGS 0x2 Retrieve the PDUs from the retransmit
queue queue
ACTION_DROP_MSGS 0x3 Drop the PDUs in the retransmit queue ACTION_DROP_MSGS 0x3 Drop the PDUs in the retransmit queue
In the Retrieval Request message, the fsn_bsn field contains the FSN of In the Retrieval Request message, the fsn_bsn field SHOULD be ignored if
the far end if the action is ACTION_RTRV_MSGS. the Action field is ACTION_RTRV_BSN or ACTION_DROP_MSGS. The fsn_bsn
field contains the FSN of the far end if the Action is ACTION_RTRV_MSGS.
When the Signaling Gateway sends a Retrieval Confirm to this request, When the Signaling Gateway sends a Retrieval Confirm to this request,
it echos the action and puts the BSN in the fsn_bsn field if the action it echos the action and puts the BSN in the fsn_bsn field if the action
was ACTION_RTRV_BSN. If there is a failure in retrieving the BSN, the was ACTION_RTRV_BSN. If there is a failure in retrieving the BSN, the
fsn_bsn should contain a -1 (0xffffffff). fsn_bsn SHOULD contain a -1 (0xffffffff). For a Retrieval Confirm with
Action of ACTION_RTRV_MSGS or ACTION_DROP_MSGS, the value received in
the fsn_bsn field in the Request message will be sent.
3.3.1.7 Retrieval Indication 3.3.1.7 Retrieval Indication
The Retrieval Indication message is sent by the Signaling Gateway The Retrieval Indication message is sent by the Signaling Gateway
with a PDU from the retransmit queue. The Retrieval Indication with a PDU from the retransmit queue. The Retrieval Indication
message does not contain the Action or fsn_bsn fields, just a PDU from message does not contain the Action or fsn_bsn fields, just a MTP3
the retransmit queue. Protocol Data Unit (PDU) from the retransmit queue.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PDU from retransmit queue | | PDU from retransmit queue |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.3.1.8 Retrieval Complete Indication 3.3.1.8 Retrieval Complete Indication
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3.3.2 Application Server Process Maintenance (ASPM) Messages 3.3.2 Application Server Process Maintenance (ASPM) Messages
The ASPM messages will only use the common message header. The ASPM messages will only use the common message header.
3.3.2.1 ASP UP (ASPUP) 3.3.2.1 ASP UP (ASPUP)
The ASP UP (ASPUP) message is used to indicate to a remote M2UA peer The ASP UP (ASPUP) message is used to indicate to a remote M2UA peer
that the Adaptation layer is ready to receive traffic or maintenance that the Adaptation layer is ready to receive traffic or maintenance
messages. messages.
The ASPUP message contains the following parameters: The ASPUP message contains the following parameters
Adaptation Layer Identifer (optional) Info String (optional)
Protocol Identifier (optional)
INFO String (optional)
The format for ASPUP Message parameters is as follows: The format for ASPUP Message parameters is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x2) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Adaptation Layer Identifier* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length | | Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| INFO String* | | INFO String* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The optional INFO String parameter can carry any meaningful 8-bit ASCII The optional INFO String parameter can carry any meaningful 8-bit ASCII
character string along with the message. Length of the INFO String character string along with the message. Length of the INFO String
parameter is from 0 to 255 characters. No procedures are presently parameter is from 0 to 255 characters. No procedures are presently
identified for its use but the INFO String may be used for debugging identified for its use but the INFO String MAY be used for debugging
purposes. purposes.
The optional Adaptation Layer Identifier (ALI) is a string that 3.3.2.2 ASP Up Ack
identifies the adaptation layer. This string must be set to "M2UA"
which results in a length of 8. The ALI would normally only be used in
the initial ASP Up message across a new SCTP association to ensure both
peers are assuming the same adaptation layer protocol.
3.3.3.2 ASP Up Ack
The ASP UP Ack message is used to acknowledge an ASP-Up message received The ASP UP Ack message is used to acknowledge an ASP Up message received
from a remote IUA peer. from a remote M2UA peer.
The ASPUP Ack message contains the following parameters: The ASPUP Ack message contains the following parameters:
Adaptation Layer Identifer (optional)
INFO String (optional) INFO String (optional)
The format for ASPUP Ack Message parameters is as follows: The format for ASPUP Ack Message parameters is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x2) | Length | | Tag (0x2) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 17, line 34 skipping to change at page 17, line 33
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length | | Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| INFO String* | | INFO String* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format and description of the optional Info String parameter is the The format and description of the optional Info String parameter is the
same as for the ASP UP message (See Section 3.3.3.1.) same as for the ASP UP message (See Section 3.3.2.1.)
The format and description of the optional Adaptation Layer Identifier (ALI)
parameter is the same as for the ASP UP message (See Section 3.3.3.1).
3.3.3.3 ASP Down (ASPDN) 3.3.2.3 ASP Down (ASPDN)
The ASP Down (ASPDN) message is used to indicate to a remote IUA peer The ASP Down (ASPDN) message is used to indicate to a remote M2UA peer
that the adaptation layer is not ready to receive traffic or that the adaptation layer is not ready to receive traffic or
maintenance messages. maintenance messages.
The ASPDN message contains the following parameters The ASPDN message contains the following parameters
Reason Reason
INFO String (Optional) INFO String (Optional)
The format for the ASPDN message parameters is as follows: The format for the ASPDN message parameters is as follows:
skipping to change at page 17, line 72 skipping to change at page 17, line 68
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format and description of the optional Info String parameter is the The format and description of the optional Info String parameter is the
same as for the ASP Up message (See Section 3.3.2.1.) same as for the ASP Up message (See Section 3.3.2.1.)
The Reason parameter indicates the reason that the remote M2UA The Reason parameter indicates the reason that the remote M2UA
adaptation layer is unavailable. The valid values for Reason are shown adaptation layer is unavailable. The valid values for Reason are shown
in the following table. in the following table.
Value Description Value Description
0x1 Management Inhibit 0x1 Management
3.4.4 ASP Down Ack 3.3.2.4 ASP Down Ack
The ASP Down Ack message is used to acknowledge an ASP-Down message The ASP Down Ack message is used to acknowledge an ASP Down message
received from a remote IUA peer. received from a remote M2UA peer.
The ASP Down Ack message contains the following parameters: The ASP Down Ack message contains the following parameters:
Reason Reason
INFO String (Optional) INFO String (Optional)
The format for the ASPDN Ack message parameters is as follows: The format for the ASPDN Ack message parameters is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
skipping to change at page 17, line 99 skipping to change at page 17, line 95
| Reason | | Reason |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length | | Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| INFO String* | | INFO String* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format and description of the optional Info String parameter is the The format and description of the optional Info String parameter is the
same as for the ASP UP message (See Section 3.3.3.1.) same as for the ASP UP message (See Section 3.3.2.1.)
The format of the Reason parameter is the same as for the ASP-Down message The format of the Reason parameter is the same as for the ASP Down message
(See Section 3.3.3.3). (See Section 3.3.2.3).
3.3.3.5 ASP Active (ASPAC) 3.3.2.5 ASP Active (ASPAC)
The ASPAC message is sent by an ASP to indicate to an SG that it is The ASPAC message is sent by an ASP to indicate to an SG that it is
Active and ready to be used. Active and ready to be used.
The ASPAC message contains the following parameters The ASPAC message contains the following parameters
Type Traffic Mode Type (Mandatory)
Interface Identifier (Optional) Interface Identifier (Optional)
- Combination of integer and integer ranges, OR
- string (text formatted)
INFO String (Optional) INFO String (Optional)
The format for the ASPAC message is as follows: The format for the ASPAC message using integer formatted Interface
Identifiers is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | | Traffic Mode Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0xx) | Length | | Tag (0x1=integer) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifiers* | | Interface Identifiers* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x8=integer range) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StartN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StopN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Additional Interface Identifiers |
| of Tag Type 0x1 or 0x8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length | | Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| INFO String* | | INFO String* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Type parameter identifies the traffic mode of operation of the ASP The format for the ASPAC message using text formatted (string)
within an AS. The valid values for Type are shown in the following Interface Identifiers is as follows:
table.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic Mode Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x3=string) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Additional Interface Identifiers |
| of Tag Type 0x3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| INFO String* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Traffic Mode Type parameter identifies the traffic mode of
operation of the ASP within an AS. The valid values for Type are
shown in the following table:
Value Description Value Description
0x1 Over-ride 0x1 Over-ride
0x2 Load-share
Within a particular Interface Identifier, only one Type can be used. Within a particular Interface Identifier, only one Type can be used.
The Over-ride value indicates that the ASP is operating in Over-ride The Over-ride value indicates that the ASP is operating in Over-ride
mode, where the ASP takes over all traffic in an Application Server mode, where the ASP takes over all traffic in an Application Server
(i.e., primary/back-up operation), over-riding any currently active (i.e., primary/back-up operation), over-riding any currently active
ASPs in the AS. In Load-share mode, the ASP will share in the ASPs in the AS.
traffic distribution with any other currently active ASPs.
The optional Interface Identifiers parameter contains a list of The optional Interface Identifiers parameter contains a list of
Interface Identifier integers indexing the Application Server traffic Interface Identifier integers (Type 0x1 or Type 0x8) or text strings
that the sending ASP is configured/registered to receive. There is (Type 0x3)indexing the Application Server traffic that the sending
one-to-one relationship between an Interface Identifier and an AS ASP is configured/registered to receive. If integer formatted
Name. Interface Identifiers are being used, the ASP can also send ranges of
Interface Identifiers (Type 0x8). Interface Identifier types Integer
(0x1) and Integer Range (0x8) are allowed in the same message. Text
formatted Interface Identifiers (0x3) cannot be used with either
Integer (0x1) or Integer Range (0x8) types.
An SG that receives an ASPAC with an incorrect type for a particular If no Interface Identifiers are included, the message is for all
Interface Identifier will respond with an Error Message. provisioned Interface Identifiers within the AS. If only a subset
of Interface Identifiers are includes, the ASP is noted as Active
for all the Interface Identifiers provisioned for the AS.
The format and description of the optional Info String parameter is the Note: If the optional Interface Identifier parameter is present, the
same as for the ASP UP message (See Section 3.3.3.1.) integer formatted Interface Identifier MUST be supported, while the
text formatted Interface Identifier MAY be supported.
A node that receives an ASPAC with an incorrect Type for a particular An SG that receives an ASPAC with an incorrect Traffic Mode Type for
Interface Identifier will respond with an Error Message (Cause: Invalid a particular Interface Identifier will respond with an Error Message
Traffic Handling Mode). (Cause: Unsupported Traffic Handling Mode).
3.3.3.6 ASP Active Ack The format and description of the optional Info String parameter is the
same as for the ASP UP message (See Section 3.3.2.1.).
3.3.2.6 ASP Active Ack
The ASPAC Ack message is used to acknowledge an ASP-Active message The ASPAC Ack message is used to acknowledge an ASP-Active message
received from a remote IUA peer. received from a remote M2UA peer.
The ASPAC Ack message contains the following parameters: The ASPAC Ack message contains the following parameters:
Type Traffic Mode Type (Mandatory)
Interface Identifier (Optional) Interface Identifier (Optional)
- Combination of integer and integer ranges, OR
- string (text formatted)
INFO String (Optional) INFO String (Optional)
The format for the ASPAC Ack message is as follows: The format for the ASPAC Ack message with Integer-formatted Interface
Identifiers is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | | Traffic Mode Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x1) | Length | | Tag (0x1=integer) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifiers* | | Interface Identifiers* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x8=integer range) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StartN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StopN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Additional Interface Identifiers |
| of Tag Type 0x1 or 0x8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| INFO String* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format for the ASP Active Ack message using text formatted (string)
Interface Identifiers is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic Mode Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x3=string) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Additional Interface Identifiers |
| of Tag Type 0x3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length | | Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| INFO String* | | INFO String* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format and description of the optional Info String parameter is the The format and description of the optional Info String parameter is the
same as for the ASP UP message (See Section 3.3.3.1.) same as for the ASP UP message (See Section 3.3.2.1.)
The format of the Type and Interface Identifier parameters is the same The format of the Type and Interface Identifier parameters is the same
as for the ASP Active message (See Section 3.3.3.5). as for the ASP Active message (See Section 3.3.2.5).
3.3.3.7 ASP Inactive (ASPIA) 3.3.2.7 ASP Inactive (ASPIA)
The ASPIA message is sent by an ASP to indicate to an SG that it is no The ASPIA message is sent by an ASP to indicate to an SG that it is no
longer an active ASP to be used from within a list of ASPs. The SG will longer an active ASP to be used from within a list of ASPs. The SG will
respond with an ASPIA message and either discard incoming messages or respond with an ASPIA Ack message and either discard incoming messages
buffer for a timed period and then discard. or buffer for a timed period and then discard.
The ASPIA message contains the following parameters The ASPIA message contains the following parameters
Type Traffic Mode Type (Mandatory)
Interface Identifiers (Optional) Interface Identifiers (Optional)
- Combination of integer and integer ranges, OR
- string (text formatted)
INFO String (Optional) INFO String (Optional)
The format for the ASPIA message parameters is as follows: The format for the ASP Inactive message parameters using Integer
formatted Interface Identifiers is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | | Traffic Mode Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x1) | Length | | Tag (0x1=integer) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifiers* | | Interface Identifiers* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x8=integer range) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StartN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StopN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Additional Interface Identifiers |
| of Tag Type 0x1 or 0x8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length | | Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| INFO String* | | INFO String* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Type parameter identifies the traffic mode of operation of the ASP The format for the ASP Inactive message using text formatted (string)
within an AS. The valid values for Type are shown in the following table. Interface Identifiers is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic Mode Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x3=string) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Additional Interface Identifiers |
| of Tag Type 0x3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| INFO String* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Traffic Mode Type parameter identifies the traffic mode of
operation of the ASP within an AS. The valid values for Traffic Mode
Type are shown in the following table:
Value Description Value Description
0x1 Over-ride 0x1 Over-ride
0x2 Load-share
The format and description of the optional Interface Identifiers and The format and description of the optional Interface Identifiers and
Info String parameters is the same as for the ASP Active message (See Info String parameters is the same as for the ASP Active message (See
Section 3.3.3.3.) Section 3.3.2.3.)
The optional Interface Identifiers parameter contains a list of The optional Interface Identifiers parameter contains a list of
Interface Identifier integers indexing the Application Server traffic Interface Identifier integers indexing the Application Server traffic
that the sending ASP is configured/registered to receive, but does not that the sending ASP is configured/registered to receive, but does not
want to receive at this time. want to receive at this time.
3.3.3.8 ASP Inactive Ack 3.3.2.8 ASP Inactive Ack
The ASPIA Ack message is used to acknowledge an ASP-Inactive message The ASPIA Ack message is used to acknowledge an ASP-Inactive message
received from a remote IUA peer. received from a remote M2UA peer.
The ASPIA Ack message contains the following parameters: The ASPIA Ack message contains the following parameters:
Type Traffic Mode Type (Mandatory)
Routing Context (Optional) Interface Identifiers (Optional)
- Combination of integer and integer ranges, OR
- string (text formatted)
INFO String (Optional) INFO String (Optional)
The format for the ASPIA Ack message is as follows: The format for the ASPIA Ack message is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | | Traffic Mode Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x6) | Length | | Tag (0x1=integer) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Routing Context* | | Interface Identifiers* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x8=integer range) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StartN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StopN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Additional Interface Identifiers |
| of Tag Type 0x1 or 0x8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length | | Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| INFO String* | | INFO String* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format and description of the optional Info String parameter is The format for the ASP Inactive Ack message using text formatted
the same as for the ASP UP message (See Section 3.3.3.1.) (string) Interface Identifiers is as follows:
The format of the Type and Routing Context parameters is the same as 0 1 2 3
for the ASP-Inctive message (See Section 3.3.3.7). 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic Mode Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x3=string) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.4.9 Heartbeat (BEAT) | Interface Identifier* |
The Heartbeat message is optionally used to ensure that the IUA peers +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Additional Interface Identifiers |
| of Tag Type 0x3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| INFO String* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format of the Traffic Mode Type and Interface Identifier
parameters is the same as for the ASP Inactive message
(See Section 3.3.2.7).
The format and description of the optional Info String parameter is
the same as for the ASP Up message (See Section 3.3.2.1).
3.3.2.9 Heartbeat (BEAT)
The Heartbeat message is optionally used to ensure that the M2UA peers
are still available to each other. It is recommended for use when are still available to each other. It is recommended for use when
the IAU runs over a transport layer other than the SCTP, which has its the M2AU runs over a transport layer other than the SCTP, which has its
own heartbeat. own heartbeat.
The BEAT message contains no parameters. The BEAT message contains the following parameters:
Heartbeat Data Optional
The format for the BEAT message is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 9 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ \
| Heartbeat Data * |
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Heartbeat Data parameter contents are defined by the sending node.
The Heartbeat Data could include, for example, a Heartbeat Sequence
Number and, or Timestamp. The receiver of a Heartbeat message does
not process this field as it is only of significance to the sender.
The receiver MUST respond with a Heartbeat Ack message.
3.3.2.10 Heartbeat Ack (BEAT-Ack)
The Heartbeat Ack message is sent in response to a received Heartbeat
message. It includes all the parameters of the received Heartbeat
message, without any change.
3.3.3 Layer Management (MGMT) Messages 3.3.3 Layer Management (MGMT) Messages
3.3.3.1 Error (ERR) 3.3.3.1 Error (ERR)
The Error message is used to notify a peer of an error event The Error message is used to notify a peer of an error event
associated with an incoming message. For example, the message type associated with an incoming message. For example, the message type
might be unexpected given the current state, or a parameter value might might be unexpected given the current state, or a parameter value might
be invalid. be invalid.
skipping to change at page 19, line ? skipping to change at page 19, line ?
Error Code Error Code
Diagnostic Information (optional) Diagnostic Information (optional)
The format for the ERR message is as follows: The format for the ERR message is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Code | | Error Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0xx) | Length | | Tag (0x7) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Diagnostic Information* | | Diagnostic Information* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Error Code parameter indicates the reason for the Error Message. The Error Code parameter indicates the reason for the Error Message.
The Error parameter value can be one of the following values: The Error parameter value can be one of the following values:
Invalid Version 0x1 Invalid Version 0x1
Invalid Interface Identifier 0x2 Invalid Interface Identifier 0x2
Invalid Adaptation Layer Identifier 0x3 Invalid Adaptation Layer Identifier 0x3
Invalid Message Type 0x4 Invalid Message Type 0x4
Invalid Traffic Handling Mode 0x5 Unsupported Traffic Handling Mode 0x5
Unexpected Message 0x6 Unexpected Message 0x6
Protocol Error 0x7 Protocol Error 0x7
Invalid Stream Identifier 0x8 Invalid Stream Identifier 0x8
The "Invalid Version" error would be sent if a message was
received with an invalid or unsupported version. The Error message
would contain the supported version in the Common header. The
Error message could optionally provide the supported version in
the Diagnostic Information area.
The "Invalid Interface Identifier" error would be sent by a SG if
an ASP sends a message with an invalid (unconfigured) Interface
Identifier value.
The "Unsupported Traffic Handling Mode" error would be sent by a SG
if an ASP sends an ASP Active with an unsupported Traffic Handling
Mode. An example would be a case in which the SG did not support
load-sharing.
The "Unexpected Message" error would be sent by an ASP if it received
a MAUP message from an SG while it was in the Inactive state.
The "Protocol Error" error would be sent for any protocol anomaly
(i.e. a bogus message).
The "Invalid Stream Identifier" error would be sent if a message
was received on an unexpected SCTP stream (i.e. a stream that did
not have an Interface Identifier associated with it).
The "Unsupported Interface Identifier Type" error would be sent by
a SG if an ASP sends a Text formatted Interface Identifier and the
SG only supports Integer formatted Interface Identifiers. When
the ASP receives this error, it will need to resend its message with
an Integer formatted Interface Identifier.
The optional Diagnostic information can be any information germain to The optional Diagnostic information can be any information germain to
the error condition, to assist in identification of the error condition. the error condition, to assist in identification of the error condition.
In the case of an Invalid Version Error Code the Diagnostic information In the case of an Invalid Version Error Code the Diagnostic information
includes the supported Version parameter. In the other cases, the includes the supported Version parameter. In the other cases, the
Diagnostic information may be the first 40 bytes of the offending message. Diagnostic information MAY be the first 40 bytes of the offending message.
3.3.3.2 Notify (NTFY) 3.3.3.2 Notify (NTFY)
The Notify message used to provide an autonomous indication of IUA The Notify message used to provide an autonomous indication of M2UA
events to an IUA peer. events to an M2UA peer.
The NTFY message contains the following parameters: The NTFY message contains the following parameters:
Status Type Status Type
Status Identification Status Identification
Interface Identifiers (Optional) Interface Identifiers (Optional)
INFO String (Optional) INFO String (Optional)
The format for the NTFY message is as follows: The format for the Notify message with Integer-formatted Interface
Identifiers is as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status Type | Status Identification | | Status Type | Status Identification |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x1) | Length | | Tag (0x1=integer) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifiers* | | Interface Identifiers* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x8=integer range) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StartN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StopN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Additional Interface Identifiers |
| of Tag Type 0x1 or 0x8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| INFO String* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format for the Notify message with Text-formatted Interface
Identifiers is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status Type | Status Identification |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x3=string) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Additional Interface Identifiers |
| of Tag Type 0x3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length | | Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| INFO String* | | INFO String* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Status Type parameter identifies the type of the Notify message. The Status Type parameter identifies the type of the Notify message.
The following are the valid Status Type values: The following are the valid Status Type values:
Value Description Value Description
0x1 Application Server state change (AS_State_Change) 0x1 Application Server state change (AS_State_Change)
0x2 Other 0x2 Other
The Status Information parameter contains more detailed information for The Status Information parameter contains more detailed information for
the notification, based on the value of the Status Type. If the Status the notification, based on the value of the Status Type. If the Status
Type is AS_State_Change the following Status Information values are used: Type is AS_State_Change the following Status Information values are used:
Value Description Value Description
0x1 Application Server Down (AS_Down) 1 Application Server Down (AS_Down)
0x2 Application Server Up (AS_Up) 2 Application Server Inactive (AS_Inactive)
0x3 Application Server Active (AS_Active) 3 Application Server Active (AS_Active)
0x4 Application Server Pending (AS_Pending) 4 Application Server Pending (AS_Pending)
0x5 Alternate ASP Active
These notifications are sent from an SG to an ASP upon a change in status These notifications are sent from an SG to an ASP upon a change in status
of a particular Application Server. The value reflects the new state of of a particular Application Server. The value reflects the new state of
the Application Server. the Application Server.
If the Status Type is Other, then the following Status Information values If the Status Type is Other, then the following Status Information values
are defined: are defined:
Value Description Value Description
0x1 Insufficient ASP resources active in AS 1 Insufficient ASP resources active in AS
2 Alternate ASP Active
This notification is not based on the SG reporting the state change of an This notification is not based on the SG reporting the state change of an
ASP or AS. For the value defined the SG is indicating to an ASP(s) in ASP or AS. In the Insufficient ASP Resources case, the SG is
the AS that another ASP is required in order to handle the load of the AS. indicating to an "Inactive" ASP(s) in the AS that another ASP is
required in order to handle the load of the AS (Load-sharing mode).
For the Alternate ASP Active case, an ASP is informed when an alternate
ASP transitions to the ASP-Active state in Over-ride mode.
The format and description of the optional Interface Identifiers and The format and description of the optional Interface Identifiers and
Info String parameters is the same as for the ASP Active message Info String parameters is the same as for the ASP Active message
(See Section 3.3.3.3.) (See Section 3.3.2.3.)
4.0 Procedures 4.0 Procedures
The M2UA layers needs to respond to various primitives it receives from The M2UA layers needs to respond to various primitives it receives from
other layers as well as messages it receives from the peer-to-peer other layers as well as messages it receives from the peer-to-peer
messages. This section describes various procedures involved in messages. This section describes various procedures involved in
response to these events. response to these events.
4.1 Procedures to Support Service in Section 1.4.1 4.1 Procedures to Support Service in Section 1.4.1
These procedures achieve the M2UA layer's "Transport of MTP Level 2 / These procedures achieve the M2UA layer's "Transport of MTP Level 2 /
MTP Level 3 boundary" service. MTP Level 3 boundary" service.
4.1.1 MTP Level 2 / MTP Level 3 Boundary Procedures 4.1.1 MTP Level 2 / MTP Level 3 Boundary Procedures
On receiving a primitive from the local upper layer, the M2UA layer will On receiving a primitive from the local upper layer, the M2UA layer will
send the corresponding MAUP message (see Section 2) to its peer. The send the corresponding MAUP message (see Section 2) to its peer. The
M2UA layer must fill in various fields of the common and specific headers M2UA layer MUST fill in various fields of the common and specific headers
correctly. In addition the message needs to be sent on the SCTP stream correctly. In addition the message needs to be sent on the SCTP stream
that corresponds to the SS7 link. that corresponds to the SS7 link.
4.1.2 MAUP Message Procedures 4.1.2 MAUP Message Procedures
On receiving MAUP messages from a peer M2UA layer, the M2UA layer on an On receiving MAUP messages from a peer M2UA layer, the M2UA layer on an
SG or MGC needs to invoke the corresponding layer primitives to the SG or MGC needs to invoke the corresponding layer primitives to the
local MTP Level 2 or MTP Level 3 layer. local MTP Level 2 or MTP Level 3 layer.
4.2 Procedures to Support Service in Section 1.4.2 4.2 Procedures to Support Service in Section 1.4.2
These procedures achieve the M2UA layer's "Support for Communication These procedures achieve the M2UA layer's "Support for Communication
between Layer Managements" service. between Layer Managements" service.
4.2.1 Layer Management Primitives Procedure 4.2.1 Layer Management Primitives Procedure
On receiving these primitives from the local layer, the M2UA layer will On receiving these primitives from the local layer, the M2UA layer will
send the corresponding MGMT message (Error) to its peer. The M2UA layer send the corresponding MGMT message (Error) to its peer. The M2UA layer
must fill in the various fields of the common and specific headers MUST fill in the various fields of the common and specific headers
correctly. correctly.
An M-SCTP ESTABLISH request from Layer Management will initiate the
establishment of an SCTP association. An M-SCTP ESTABLISH confirm
will be sent to Layer Management when the initiated association set-up
is complete. An M-SCTP ESTABLISH indication is sent to Layer
Management upon successful completion of an incoming SCTP association
set-up from a peer M2UA node
An M-SCTP RELEASE request from Layer Management will initiate the
tear-down of an SCTP association. An M-SCTP RELEASE confirm will
be sent by Layer Management when the association teardown is complete.
An M-SCTP RELEASE indication is sent to Layer Management upon
successful tear-down of an SCTP association initiated by a peer M2UA.
M-SCTP STATUS request and indication support a Layer Management
query of the local status of a particular SCTP association.
M-NOTIFY indication and M-ERROR indication indicate to Layer
Management the notification or error information contained in a
received M2UA Notify or Error message respectively. These indications
can also be generated based on local M2UA events.
M-ASP STATUS request/indication and M-AS-STATUS request/indication
support a Layer Management query of the local status of a particular
ASP or AS. No M2UA peer protocol is invoked.
M-ASP Up request, M-ASP Down request, M-ASP-INACTIVE request and
M-ASP-ACTIVE request allow Layer Management at an ASP to initiate
state changes. These requests result in outgoing M2UA ASP UP,
ASP DOWN, ASP INACTIVE and ASP ACTIVE messages.
M-ASP Up confirmation, M-ASP Down confirmation, M-ASP-INACTIVE
confirmation and M-ASP-ACTIVE confirmation indicate to Layer
Management that the previous request has been confirmed.
All MGMT messages are sent on a sequenced stream to ensure ordering.
SCTP stream '0' SHOULD be used.
4.2.2 MGMT message procedures 4.2.2 MGMT message procedures
Upon receipt of MGMT messages the M2UA layer must invoke the corresponding Upon receipt of MGMT messages the M2UA layer MUST invoke the corresponding
Layer Management primitives (M-ERROR) to the local layer management. Layer Management primitives indications (e.g., M-AS Status ind., M-ASP
Status ind., M-ERROR ind...) to the local layer management.
M-NOTIFY indication and M-ERROR indication indicate to Layer Management
the notification or error information contained in a received M2UA
Notify or Error message. These indications can also be generated
based on local M2UA events.
All MGMT messages are sent on a sequenced stream to ensure ordering.
SCTP stream '0' SHOULD be used.
4.3 Procedures to Support Service in Section 1.4.3 4.3 Procedures to Support Service in Section 1.4.3
These procedures achieve the M2UA layer's "Support for management of These procedures achieve the M2UA layer's "Support for management of
active associations between SG and MGC" service. active associations between SG and MGC" service.
4.3.1 State Maintenance 4.3.1 State Maintenance
The M2UA layer on the SG maintains the state of each AS, in each The M2UA layer on the SG maintains the state of each AS, in each
Appliction Server that it is configured to receive traffic. Appliction Server that it is configured to receive traffic.
4.3.1.1 ASP States 4.3.1.1 ASP States
The state of the each ASP, in each AS that it is configured, is The state of the each ASP, in each AS that it is configured, is
maintained in the IUA layer on the SG. The state of an ASP changes maintained in the M2UA layer on the SG. The state of an ASP changes
due to events. The events include due to events. The events include
* Reception of messages from peer IUA layer at that ASP * Reception of messages from peer M2UA layer at that ASP
* Reception of some messages from the peer IUA layer at other * Reception of some messages from the peer M2UA layer at other
ASPs in the AS ASPs in the AS
* Reception of indications from SCTP layer * Reception of indications from SCTP layer
* Switch-over Time triggers
The ASP state transition diagram is shown in Figure 4. The possible The ASP state transition diagram is shown in Figure 6. The possible
states of an ASP are the following: states of an ASP are the following:
ASP-DOWN Application Server Process is unavailable and/or the SCTP ASP Down: Application Server Process is unavailable and/or the related
association is down. Initially all ASPs will be in this state. SCTP association is down. Initially all ASPs will be in this state.
An ASP in this state SHOULD NOT not be sent any M2UA messages.
ASP-UP The remote IUA peer at the ASP is available (and the SCTP ASP-INACTIVE: The remote M2UA peer at the ASP is available (and the
association is up) but application traffic is stopped. related SCTP association is up) but application traffic is stopped.
In this state the ASP can be sent any non-MAUP M2UA messages.
ASP-ACTIVE The remote IUA peer at the ASP is available and ASP-ACTIVE The remote M2UA peer at the ASP is available and
application traffic is active. application traffic is active.
Figure 4 ASP State Transition Diagram Figure 6 ASP State Transition Diagram
+-------------+ +-------------+
+----------------------| | +----------------------| |
| Alternate +-------| ASP-ACTIVE |<------------+ | Alternate +-------| ASP-ACTIVE |
| ASP | +-------------+ | | ASP | +-------------+
| Takeover | ^ | | | Takeover | ^ |
| | ASP | | ASP | | | ASP | | ASP
| | Active | | Inactive | ASP | | Active | | Inactive
| | | v |Takeover | | | v
| | +-------------+ | | | +-------------+
| | | |-------------+
| +------>| ASP-UP |-------------+
| +-------------+ |
| ^ | |
ASP Down/ | ASP | | ASP Down / | ASP
SCTP CDI | Up | | SCTP CDI | Down/
| | v | SCTP
| +-------------+ | CDI
| | | | | | | |
+--------------------->| |<------------+ | +------>| ASP-INACT |
| ASP-DOWN | | +-------------+
| ^ |
ASP Down/ | ASP | | ASP Down /
SCTP CDI | Up | | SCTP CDI
| | v
| +-------------+
+--------------------->| |
| ASP Down |
+-------------+ +-------------+
SCTP CDI The local SCTP layer's Communication Down Indication to the SCTP CDI The local SCTP layer's Communication Down Indication to the
Upper Layer Protocol (IUA) on an SG. The local SCTP will send this Upper Layer Protocol (M2UA) on an SG. The local SCTP will send this
indication when it detects the loss of connectivity to the ASP's peer indication when it detects the loss of connectivity to the ASP's peer
SCTP layer. SCTP layer. SCTP CDI is understood as either a SHUTDOWN COMPLETE
notification and COMMUNICATION LOST notification from the SCTP.
Ts Switch-over Time Triggers. This timer is configurable by the
Operator on a per AS basis. The default value of this timer should
be three seconds.
4.3.1.2 AS States 4.3.1.2 AS States
The state of the AS is maintained in the IUA layer on the SG. The state of the AS is maintained in the M2UA layer on the SG.
The state of an AS changes due to events. These events include the The state of an AS changes due to events. These events include the
following: following:
* ASP state transitions * ASP state transitions
* Recovery timer triggers * Recovery timer triggers
The possible states of an AS are the following: The possible states of an AS are the following:
AS-DOWN The Application Server is unavailable. This state implies AS-DOWN: The Application Server is unavailable. This state implies
that all related ASPs are in the ASP-DOWN state for this AS. that all related ASPs are in the ASP Down state for this AS.
Initially the AS will be in this state. Initially the AS will be in this state.
AS-UP The Application Server is available but no application traffic AS-INACTIVE: The Application Server is available but no application traffic
is active (i.e., one or more related ASPs are in the ASP-UP state, is active (i.e., one or more related ASPs are in the ASP-Inactive state,
but none in the ASP-Active state). but none in the ASP-Active state).
AS-ACTIVE The Application Server is available and application traffic AS-ACTIVE: The Application Server is available and application traffic
is active. This state implies that one ASP is in the ASP-ACTIVE state. is active. This state implies that one ASP is in the ASP-ACTIVE state.
AS-PENDING An active ASP has transitioned from active to inactive or AS-PENDING: An active ASP has transitioned from active to inactive or
down and it was the last remaining active ASP in the AS. A recovery down and it was the last remaining active ASP in the AS. A recovery
timer T(r) will be started and all incoming SCN messages will be timer T(r) will be started and all incoming SCN messages will be
queued by the SG. If an ASP becomes active before T(r) expires, the queued by the SG. If an ASP becomes active before T(r) expires, the
AS will move to AS-ACTIVE state and all the queued messages will be AS will move to AS-ACTIVE state and all the queued messages will be
sent to the active ASP. sent to the active ASP.
If T(r) expires before an ASP becomes active, the SG stops queuing If T(r) expires before an ASP becomes active, the SG stops queuing
messages and discards all previously queued messages. The AS will move messages and discards all previously queued messages. The AS will move
to AS-UP if at least one ASP is in ASP-UP state, otherwise it will move to AS-Inactive if at least one ASP is in ASP-Inactive state, otherwise it
to AS-DOWN state. will move to AS-DOWN state.
Figure 5 AS State Transition Diagram Figure 7 AS State Transition Diagram
+----------+ one ASP trans ACTIVE +-------------+ +----------+ one ASP trans ACTIVE +-------------+
| |------------------------>| | | |------------------------>| |
| AS-UP | | AS-ACTIVE | | AS-INACT | | AS-ACTIVE |
| | | | | | | |
| |< -| | | |< | |
+----------+ \ / +-------------+ +----------+ \ +-------------+
^ | \ Tr Trigger / ^ | ^ | \ Tr Trigger ^ |
| | \ at least one / | | | | \ at least one | |
| | \ ASP in UP / | | | | \ ASP in UP | |
| | \ / | | | | \ | |
| | \ / | | | | \ | |
| | \ /---/ | | | | \ | |
one ASP | | \ / one ASP | | Last ACTIVE ASP one ASP | | \ one ASP | | Last ACTIVE ASP
trans | | all ASP \-/----\ trans to | | trans to UP or trans | | all ASP \------\ trans to | | trans to INACT
to UP | | trans to / \ ACTIVE | | DOWN to | | trans to \ ACTIVE | | or DOWN
| | DOWN / \ | | INACT | | DOWN \ | | (start Tr timer)
| | / \ | | | | \ | |
| | / \ | | | | \ | |
| | /all ASP \ | | | | \ | |
| v / trans to \ | v | v \ | v
+----------+ / DOWN \ +-------------+ +----------+ \ +-------------+
| |<--/ -| | | | -| |
| AS-DOWN | | AS-PENDING | | AS-DOWN | | AS-PENDING |
| | | (queueing) | | | | (queueing) |
| |<------------------------| | | |<------------------------| |
+----------+ Tr Trigger no ASP +-------------+ +----------+ Tr Expiry and no +-------------+
in UP state ASP in INACTIVE state
Tr = Recovery Timer Tr = Recovery Timer
4.3.2 ASPM procedures for primitives 4.3.2 ASPM procedures for primitives
Before the establishment of an SCTP association the ASP state at both Before the establishment of an SCTP association the ASP state at both
the SG and ASP is assumed to be "Down". the SG and ASP is assumed to be "Down".
As the ASP is responsible for initiating the setup of an SCTP As the ASP is responsible for initiating the setup of an SCTP
association to an SG, the IUA layer at an ASP receives an M-SCTP association to an SG, the M2UA layer at an ASP receives an M-SCTP
ESTABLISH request primitive from the Layer Management, the IUA layer ESTABLISH request primitive from the Layer Management, the M2UA layer
will try to establish an SCTP association with the remote IUA peer at will try to establish an SCTP association with the remote M2UA peer at
an SG. Upon reception of an eventual SCTP-Communication Up confirm an SG. Upon reception of an eventual SCTP-Communication Up confirm
primitive from the SCTP, the IUA layer will invoke the primitive primitive from the SCTP, the M2UA layer will invoke the primitive
M-SCTP ESTABLISH confirm to the Layer Management. M-SCTP ESTABLISH confirm to the Layer Management.
At the SG, the IUA layer will receive an SCTP Communication Up At the SG, the M2UA layer will receive an SCTP Communication Up
indication primitive from the SCTP. The IUA layer will then invoke indication primitive from the SCTP. The M2UA layer will then invoke
the primitive M-SCTP ESTABLISH indication to the Layer Management. the primitive M-SCTP ESTABLISH indication to the Layer Management.
Once the SCTP association is establishedand assuming that the local Once the SCTP association is establishedand assuming that the local
IUA-User is ready, the local ASP IUA Application Server Process M2UA-User is ready, the local ASP M2UA Application Server Process
Maintenance (ASPM) function will initiate the ASPM procedures, using Maintenance (ASPM) function will initiate the ASPM procedures, using
the ASP-Up/-Down/-Active/-Inactive messages to convey the ASP-state to the ASP Up/-Down/-Active/-Inactive messages to convey the ASP-state to
the SG - see Section 4.3.3. the SG - see Section 4.3.3.
The Layer Management and the IUA layer on SG can communicate the The Layer Management and the M2UA layer on SG can communicate the
status of the application server using the M-AS STATUS primitives. status of the application server using the M-AS STATUS primitives.
The Layer Managements and the IUA layers on both the SG and ASP The Layer Managements and the M2UA layers on both the SG and ASP
can communicate the status of an SCTP association using the can communicate the status of an SCTP association using the
M-SCTP STATUS primitives. M-SCTP STATUS primitives.
If the Layer Management on SG or ASP wants to bring down an SCTP If the Layer Management on SG or ASP wants to bring down an SCTP
association for management reasons, they would send M-SCTP RELEASE association for management reasons, they would send M-SCTP RELEASE
request primitive to the local IUA layer. The IUA layer would release request primitive to the local M2UA layer. The M2UA layer would release
the SCTP association and upon receiving the SCTP Communication Down the SCTP association and upon receiving the SCTP Communication Down
indication from the underlying SCTP layer, it would inform the local indication from the underlying SCTP layer, it would inform the local
Layer Management using M-SCTP RELEASE confirm primitive. Layer Management using M-SCTP RELEASE confirm primitive.
If the IUA layer receives an SCTP-Communication Down indication If the M2UA layer receives an SCTP-Communication Down indication
from the underlying SCTP layer, it will inform the Layer from the underlying SCTP layer, it will inform the Layer
Management by invoking the M-SCTP RELEASE indication primitive. The Management by invoking the M-SCTP RELEASE indication primitive. The
state of the ASP will be moved to "Down" at both the SG and ASP. state of the ASP will be moved to "Down" at both the SG and ASP.
At an ASP, the Layer Management may try to reestablish the SCTP At an ASP, the Layer Management MAY try to reestablish the SCTP
association using M-SCTP ESTABLISH request primitive. association using M-SCTP ESTABLISH request primitive.
4.3.3 ASPM procedures for peer-to-peer messages 4.3.3 ASPM procedures for peer-to-peer messages
All ASPM messages are sent on a sequenced stream to ensure ordering. All ASPM messages are sent on a sequenced stream to ensure ordering.
SCTP stream Š0Ă is used. SCTP stream '0' SHOULD is used.
4.3.3.2 ASP-Up 4.3.3.1 ASP-Inactive
After an ASP has successfully established an SCTP association to an SG, After an ASP has successfully established an SCTP association to an SG,
the SG waits for the ASP to send an ASP-Up message, indicating that the the SG waits for the ASP to send an ASP Up message, indicating that the
ASP IUA peer is available. The ASP is always the initiator of the ASP M2UA peer is available. The ASP is always the initiator of the
ASP-Up exchange. ASP Up exchange.
When an ASP-Up message is received at an SG and internally the ASP is When an ASP Up message is received at an SG and internally the ASP is
not considered locked-out for local management reasons, the SG marks not considered locked-out for local management reasons, the SG marks
the remote ASP as Up. The SG responds with an ASP-Up Ack message in the remote ASP as Inactive. The SG responds with an ASP Up Ack message
acknowledgement. The SG sends an-Up Ack message in response to a in acknowledgement. The SG sends an-Up Ack message in response to a
received ASP-Up message even if the ASP is already marked as "Up" received ASP Up message even if the ASP is already marked as "Inactive"
at the SG. at the SG.
If for any local reason the SG cannot respond with an ASP-Up, the SG If for any local reason the SG cannot respond with an ASP Up, the SG
responds to a ASP-Up with a Notify (ASP-Down) message. responds to a ASP Up with a ASP Down Ack message.
At the ASP, the ASP-Up Ack message received from the SG is not At the ASP, the ASP Up Ack message received from the SG is not
acknowledged by the ASP. If the ASP does not receive a response from acknowledged by the ASP. If the ASP does not receive a response from
the SG, or an ASP-Down is received, the ASP may resend ASP-Up messages the SG, or an ASP Down is received, the ASP MAY resend ASP Up messages
every 2 seconds until it receives a Notify (ASP-Up) message from the every 2 seconds until it receives a ASP Up Ack message from the
SG. The ASP may decide to reduce the frequency (say to every 5 SG. The ASP MAY decide to reduce the frequency (say to every 5
seconds) if an ASP-Up Ack is not received after a few tries. seconds) if an ASP Up Ack is not received after a few tries.
The ASP must wait for the ASP-Up Ack message from the SG before The ASP MUST wait for the ASP Up Ack message from the SG before
sending any ASP traffic control messages (ASPAC or ASPIA) or Data sending any ASP traffic control messages (ASPAC or ASPIA) or Data
messages or it will risk message loss. If the SG receives Data messages or it will risk message loss. If the SG receives Data
messages before an ASP Up is received, the SG should discard. messages before an ASP Up is received, the SG SHOULD discard.
4.3.3.2 ASP-Down 4.3.3.2 ASP Down
The ASP will send an ASP-Down to an SG when the ASP is to be removed The ASP will send an ASP Down to an SG when the ASP is to be removed
from the list of ASPs in all Application Servers that it is a member. from the list of ASPs in all Application Servers that it is a member
and no longer receive any M2UA traffic or management messages.
The SG marks the ASP as "Down" and returns an ASP-Down Ack message to Whether the ASP is permanently removed from an AS is a function of
configuration management.
The SG marks the ASP as "Down" and returns an ASP Down Ack message to
the ASP if one of the following events occur: the ASP if one of the following events occur:
- an ASP-Down message is received from the ASP, - an ASP Down message is received from the ASP,
- another ASPM message is received from the ASP and the SG has - another ASPM message is received from the ASP and the SG has
locked out the ASP for management reasons. locked out the ASP for management reasons.
The SG sends anASP-Down Ack message in response to a received ASP-Down The SG sends anASP Down Ack message in response to a received ASP Down
message from the ASP even if the ASP is already marked as "Down" at message from the ASP even if the ASP is already marked as "Down" at
the SG. the SG.
If the ASP does not receive a response from the SG, the ASP may send If the ASP does not receive a response from the SG, the ASP MAY send
ASP-Down messages every 2 seconds until it receives an ASP-Down Ack ASP Down messages every 2 seconds until it receives an ASP Down Ack
message from the SG or the SCTP association goes down. The ASP may message from the SG or the SCTP association goes down. The ASP MAY
decide to reduce the frequency (say to every 5 seconds) if an ASP-Down decide to reduce the frequency (say to every 5 seconds) if an ASP Down
Ack is not received after a few tries. Ack is not received after a few tries.
4.3.3.3 M2UA Version Control 4.3.3.3 M2UA Version Control
If a ASP-Up message with an unsupported version is received, the If a ASP Up message with an unsupported version is received, the
receiving end responds with an Error message, indicating the version the receiving end responds with an Error message, indicating the version the
receiving node supports. receiving node supports.
This is useful when protocol version upgrades are being performed in a This is useful when protocol version upgrades are being performed in a
network. A node upgraded to a newer version should support the older network. A node upgraded to a newer version SHOULD support the older
versions used on other nodes it is communicating with. Because ASPs versions used on other nodes it is communicating with. Because ASPs
initiate the ASP-Up procedure it is assumed that the Error message would initiate the ASP Up procedure it is assumed that the Error message would
normally come from the SG. normally come from the SG.
4.3.3.4 ASP-Active 4.3.3.4 ASP-Active
Any time after the ASP has received a ASP-Up Ack from the SG, the ASP Any time after the ASP has received a ASP Up Ack from the SG, the ASP
sends an ASP-Active (ASPAC) to the SG indicating that the ASP is ready sends an ASP Active (ASPAC) to the SG indicating that the ASP is ready
to start processing traffic. In the case where an ASP is configured/- to start processing traffic. In the case where an ASP is configured/-
registered to process the traffic for more than one Application Server registered to process the traffic for more than one Application Server
across an SCTP association, the ASPAC contains one or more Interface across an SCTP association, the ASPAC contains one or more Interface
Identifiers to indicate for which Application Servers the ASPAC applies. Identifiers to indicate for which Application Servers the ASPAC applies.
When an ASP Active (ASPAC) message is received, the SG responds to the When an ASP Active (ASPAC) message is received, the SG responds to the
ASP with a ASPAC Ack message acknowledging that the ASPAC was received ASP with a ASPAC Ack message acknowledging that the ASPAC was received
and starts sending traffic for the associated Application Server(s) and starts sending traffic for the associated Application Server(s)
to that ASP. to that ASP.
There are two modes of Application Server traffic handling in the SG The ASP MUST wait for the ASP-Active Ack message from the SG before
IUA - Over-ride and Load-balancing. The Type parameter in the ASPAC sending any Data messages or it will risk message loss. If the SG
messge indicates the mode used in a particular Application Server. If receives MAUP messages before an ASP Active is received, the SG SHOULD
the SG determines that the mode indicates in an ASPAC is incompatible discard these messages.
with the traffic handling mode currently used in the AS, the SG responds
with an Error message indicating Invalid Traffic Handling Mode.
In the case of an Over-ride mode AS, reception of an ASPAC message at There is one mode of Application Server traffic handling in the SG
an SG causes the redirection of all traffic for the AS to the ASP that M2UA - Over-ride. The Type parameter in the ASPAC messge indicates the
sent the ASPAC. The SG responds to the ASPAC with an ASP-Active Ack mode used in a particular Application Server. If the SG determines that
message to the ASP. Any previously active ASP in the AS is now the mode indicates in an ASPAC is incompatible with the traffic handling
considered Inactive and will no longer receive traffic from the SG mode currently used in the AS, the SG responds with an Error message
within the AS. The SG sends a Notify (Alternate ASP-Active) to the indicating Unsupported Traffic Handling Mode.
previously active ASP in the AS, after stopping all traffic to that
ASP.
In the case of a load-share mode AS, reception of an ASPAC message at For Over-ride mode AS, the reception of an ASPAC message at an SG causes
an SG causes the direction of traffic to the ASP sending the ASPAC, the redirection of all traffic for the AS to the ASP that sent the ASPAC.
in addition to all the other ASPs that are currently active in the AS. The SG responds to the ASPAC with an ASP-Active Ack message to the ASP.
The algorithm at the SG for loadsharing traffic within an AS to all Any previously active ASP in the AS is now considered Inactive and will
the active ASPs is application and network dependent. The algorithm no longer receive traffic from the SG within the AS. The SG sends a
could, for example be round-robin or based on information in the Data Notify (Alternate ASP-Active) to the previously active ASP in the AS,
message, such as Interface ID, depending on the requirements of the after stopping all traffic to that ASP.
application and the call state handling assumptions of the collection
of ASPs in the AS. The SG responds to the ASPAC with a ASP-Active Ack
message to the ASP.
4.3.3.5 ASP Inactive 4.3.3.5 ASP Inactive
When an ASP wishes to withdraw from receiving traffic within an AS, When an ASP wishes to withdraw from receiving traffic within an AS,
the ASP sends an ASP Inactive (ASPIA) to the SG. In the case where the ASP sends an ASP Inactive (ASPIA) to the SG. In the case where
an ASP is configured/registered to process the traffic for more than an ASP is configured/registered to process the traffic for more than
one Application Server across an SCTP association, the ASPIA contains one Application Server across an SCTP association, the ASPIA contains
one or more Interface Ids to indicate for which Application Servers one or more Interface Ids to indicate for which Application Servers
the ASPIA applies. the ASPIA applies.
There are two modes of Application Server traffic handling in the SG There is one mode of Application Server traffic handling in the SG
IUA when withdrawing an ASP from service - Over-ride and Load-balancing. M2UA when withdrawing an ASP from service - Over-ride. The Type
The Type parameter in the ASPIA messge indicates the mode used in a parameter in the ASPIA messge indicates the mode used in a particular
particular Application Server. If the SG determines that the mode Application Server. If the SG determines that the mode indicates in an
indicates in an ASPAC is incompatible with the traffic handling mode ASPAC is incompatible with the traffic handling mode currently used in
currently used in the AS, the SG responds with an Error message the AS, the SG responds with an Error message indicating Unsupported
indicating Invalid Traffic Handling Mode. Traffic Handling Mode.
In the case of an Over-ride mode AS, where normally another ASP has In the case of an Over-ride mode AS, where normally another ASP has
already taken over the traffic within the AS with an Over-ride ASPAC, already taken over the traffic within the AS with an Over-ride ASPAC,
the ASP which sends the ASPIA is already considered by the SG to be the ASP which sends the ASPIA is already considered by the SG to be
"Inactive" (i.e., in the "Up" state). An ASPIA Ack message is sent "Inactive" (i.e., in the "Inactive" state). An ASPIA Ack message is
to the ASP, after ensuring that all traffic is stopped to the ASP. sent to the ASP, after ensuring that all traffic is stopped to the ASP.
In the case of a Loadshare mode AS, the SG moves the ASP to the "Up"
state and the AS traffic is re-allocated across the remaining
"active" ASPs per the load-sharing algorithm currently used within
the AS. AnASPIA Ack message is sent to the ASP after all traffic
is halted to the ASP.
If no other ASPs are Active in the Application Server, the SG either If no other ASPs are Active in the Application Server, the SG either
discards all incoming messages for the AS or starts buffering the discards all incoming messages for the AS or starts buffering the
incoming messages for T(r)seconds, after which messages will be incoming messages for T(r)seconds, after which messages will be
discarded. T(r) is configurable by the network operator. If the SG discarded. T(r) is configurable by the network operator. If the SG
receives an ASPAC from an ASP in the AS before expiry of T(r), the receives an ASPAC from an ASP in the AS before expiry of T(r), the
buffered traffic is directed to the ASP and the timer is cancelled. buffered traffic is directed to the ASP and the timer is cancelled.
If T(r) expires, the AS is moved to the "Down" state.
4.3.3.5 Notify 4.3.3.6 Notify
In the case where a Notify (AS-Up) message is sent by an SG that now A Notify message reflecting a change in the AS state is sent to all
has no ASPs active to service the traffic, the Notify does not force ASPs in the AS, except those in the "Down" state, with appropriate
the ASP(s) receiving the message to become active. The ASPs remain in Status Identification.
control of what (and when) action is taken.
In the case where a Notify (AS-Pending) message is sent by an SG
that now has no ASPs active to service the traffic, the Notify does
not explicitly force the ASP(s) receiving the message to become
active. The ASPs remain in control of what (and when) action is
taken.
4.3.3.6 Heartbeat 4.3.3.6 Heartbeat
The optional Heartbeat procedures may be used when operating over The optional Heartbeat procedures MAY be used when operating over
transport layers that do not have their own heartbeat mechanism for transport layers that do not have their own heartbeat mechanism for
detecting loss of the transport association (i.e., other than the detecting loss of the transport association (i.e., other than the
SCTP). SCTP).
Once the ASP sends an ASP-Up message to the SG, the ASP sends Beat After receiving an ASP Up Ack message from the SG in response to an
messages periodically, subject to a provisionable timer T(beat). ASP Up message, the ASP MAY optionally send Beat messages periodically,
The SG M3UA, upon receiving a BEAT message from the ASP, responds subject to a provisionable timer T(beat). The SG M2UA, upon receiving
with a BEAT message. If no BEAT message (or any other M3UA message), a BEAT message from the ASP, responds with a BEAT ACK message. If no
is received from the ASP within the timer 2*T(beat), the ASP will BEAT message (or any other M2UA message) is received from the ASP
consider the remote M3UA as 'Down". within the timer 2*T(beat), the SG will consider the remote M2UA as
"Down". The SG will also send an ASP Down Ack message to the ASP.
At the ASP, if no BEAT message (or any other M3UA message) is At the ASP, if no BEAT ACK message (or any other M2UA message) is
received from the SG within 2*T(beat), the SG is considered received from the SG within 2*T(beat), the SG is considered
unavailable. Transmission of BEAT messages is stopped and ASP-Up unavailable. Transmission of BEAT messages is stopped and ASP Up
procedures are used to re-establish communication with the SG M3UA procedures are used to re-establish communication with the SG M2UA
peer. peer.
The BEAT message MAY optionally contain an opaque Heartbeat Data
parameter that MUST be echoed back unchanged in the related Beat
Ack message. The ASP upon examining the contents of the returned
BEAT Ack message MAY choose to consider the remote ASP as
unavailable. The contents/format of the Heartbeat Data parameter is
implementation-dependent and only of local interest to the original
sender. The contents MAY be used, for example, to support a
Heartbeat sequence algorithm (to detect missing Heartbeats), and/or
a timestamp mechanism (to evaluate delays).
Note: Heartbeat related events are not shown in Figure 4 "ASP state Note: Heartbeat related events are not shown in Figure 4 "ASP state
transition diagram". transition diagram".
5.0 Examples of MTP2 User Adaptation (M2UA) Procedures 5.0 Examples of MTP2 User Adaptation (M2UA) Procedures
5.1 Establishment of associations between SG and MGC examples 5.1 Establishment of associations between SG and MGC examples
5.1.1 Single ASP in an Application Server (˘1+0÷ sparing) 5.1.1 Single ASP in an Application Server (1+0 sparing)
This scenario shows the example M2UA message flows for the establishment This scenario shows the example M2UA message flows for the establishment
of traffic between an SG and an ASP, where only one ASP is configured of traffic between an SG and an ASP, where only one ASP is configured
within an AS (no backup). It is assumed that the SCTP association is within an AS (no backup). It is assumed that the SCTP association is
already set-up. already set-up.
SG ASP1 SG ASP1
| |
|<---------ASP Up----------| |<---------ASP Up----------|
|--------ASP-Up Ack------->| |--------ASP Up Ack------->|
| | | |
|<-------ASP Active--------| |<-------ASP Active--------|
|------ASP_Active Ack----->| |------ASP_Active Ack----->|
| | | |
5.1.2 Two ASPs in Application Server (˘1+1÷ sparing) 5.1.2 Two ASPs in Application Server (1+1 sparing)
This scenario shows the example M2UA message flows for the establishment This scenario shows the example M2UA message flows for the establishment
of traffic between an SG and two ASPs in the same Application Server, of traffic between an SG and two ASPs in the same Application Server,
where ASP1 is configured to be ˘active÷ and ASP2 a ˘standby÷ in the event where ASP1 is configured to be čactive¸ and ASP2 a standby in the event
of communication failure or the withdrawal from service of ASP1. ASP2 may of communication failure or the withdrawal from service of ASP1. ASP2 MAY
act as a hot, warm, or cold standby depending on the extent to which ASP1 act as a hot, warm, or cold standby depending on the extent to which ASP1
and ASP2 share call/transaction state or can communicate call state under and ASP2 share call/transaction state or can communicate call state under
failure/withdrawal events. The example message flow is the same whether failure/withdrawal events.
the ASP-Active messages are Over-ride or Load-share mode although typically
this example would use an Over-ride mode.
SG ASP1 ASP2 SG ASP1 ASP2
| | | | | |
|<--------ASP Up----------| | |<--------ASP Up----------| |
|-------ASP-Up Ack------->| | |-------ASP Up Ack------->| |
| | | | | |
|<-----------------------------ASP Up----------------| |<-----------------------------ASP Up----------------|
|----------------------------ASP-Up Ack------------->| |----------------------------ASP Up Ack------------->|
| | | | | |
| | | | | |
|<-------ASP Active-------| | |<-------ASP Active-------| |
|-----ASP-Active Ack----->| | |-----ASP-Active Ack----->| |
| | | | | |
5.1.3 Two ASPs in an Application Server (˘1+1÷ sparing, load-sharing case)
This scenario shows a similar case to Section 5.1.2 but where the two
ASPs are brought to ˘active÷ and loadshare the traffic load. In this
case, one ASP is sufficient to handle the total traffic load.
SG ASP1 ASP2
| | |
|<---------ASP Up---------| |
|---------ASP-UpAck------>| |
| | |
|<------------------------------ASP Up---------------|
|-----------------------------ASP Up Ack------------>|
| | |
| | |
|<--ASP Active (Ldshr)----| |
|----ASP-Active Ack------>| |
| | |
|<----------------------------ASP Active (Ldshr)-----|
|-----------------------------ASP-Active Ack-------->|
| | |
5.1.4 Three ASPs in an Application Server (˘n+k÷ sparing, load-sharing case)
This scenario shows the example M2UA message flows for the establishment
of traffic between an SG and three ASPs in the same Application Server,
where two of the ASPs are brought to ˘active÷ and share the load. In
this case, a minimum of two ASPs are required to handle the total traffic
load (2+1 sparing).
SG ASP1 ASP2 ASP3
| | | |
|<------ASP Up-------| | |
|-----ASP-Up Ack---->| | |
| | | |
|<--------------------------ASP Up-------| |
|------------------------ASP-U Ack)----->| |
| | | |
|<---------------------------------------------ASP Up--------|
|-------------------------------------------ASPASP-Up Ack--->|
| | | |
| | | |
|<-ASP Act (Ldshr)---| | |
|----ASP-Act Ack---->| | |
| | | |
|<--------------------ASP Act. (Ldshr)---| |
|----------------------ASP-Act Ack------>| |
| | | |
5.2 ASP Traffic Fail-over Examples 5.2 ASP Traffic Fail-over Examples
5.2.1 (1+1 Sparing, withdrawal of ASP, Back-up Over-ride) 5.2.1 (1+1 Sparing, withdrawal of ASP, Back-up Over-ride)
Following on from the example in Section 5.1.2, and ASP withdraws from Following on from the example in Section 5.1.2, and ASP withdraws from
service: service:
SG ASP1 ASP2 SG ASP1 ASP2
| | | | | |
|<-----ASP Inactive-------| | |<-----ASP Inactive-------| |
|----ASP Inactive Ack---->| | |----ASP Inactive Ack---->| |
|--------------------NTFY(AS-Down) (Optional)------->| |--------------------NTFY(AS-Down) (Optional)------->|
| | | | | |
|<------------------------------ ASP Active----------| |<------------------------------ ASP Active----------|
|-----------------------------ASP-Active Ack)------->| |-----------------------------ASP-Active Ack)------->|
| | | |
In this case, the SG notifies ASP2 that the AS has moved to the
Down state. The SG could have also (optionally) sent a Notify
message when the AS moved to the Pending state.
Note: If the SG detects loss of the M2UA peer (M2UA heartbeat loss or Note: If the SG detects loss of the M2UA peer (M2UA heartbeat loss or
detection of SCTP failure), the initial SG-ASP1 ASP Inactive message detection of SCTP failure), the initial SG-ASP1 ASP Inactive message
exchange would not occur. exchange would not occur.
5.2.2 (1+1 Sparing, Back-up Over-ride) 5.2.2 (1+1 Sparing, Back-up Over-ride)
Following on from the example in Section 5.1.2, and ASP2 wishes to over- Following on from the example in Section 5.1.2, and ASP2 wishes to over-
ride ASP1 and take over the traffic: ride ASP1 and take over the traffic:
SG ASP1 ASP2 SG ASP1 ASP2
| | | | | |
|<------------------------------ ASP Active----------| |<------------------------------ ASP Active----------|
|-----------------------------ASP-Active Ack-------->| |-----------------------------ASP-Active Ack-------->|
|----NTFY( Alt ASP-Act)-->| |----NTFY( Alt ASP-Act)-->|
| | | | (optional) | |
5.2.3 (n+k Sparing, Load-sharing case, withdrawal of ASP) In this case, the SG notifies ASP1 that an alternative ASP has
overridden it.
Following on from the example in Section 5.1.4, and ASP1 withdraws from 5.3 SG to MGC, MTP Level 2 to MTP Level 3 Boundary Procedures
service:
SG ASP1 ASP2 ASP3 When the M2UA layer on the ASP has a MAUP message to send to the SG, it
| | | | will do the following:
|<----ASP Inact.-----| | |
|---ASP-Inact Ack--->| | |
| | | |
|---------------------------------NTFY(Ins. ASPs)(Optional)->|
| | | |
|<-----------------------------------------ASP Act (Ldshr)---|
|-------------------------------------------ASP Act (Ack)--->|
| | | |
The Notify message to ASP3 is optional, as well as the ASP-Active from - Determine the correct SG
ASP3. The optional Notify can only occur if the SG maintains knowledge
of the minimum ASP resources required - for example if the SG knows that
˘n+k÷ = ˘2+1÷ for a loadshare AS and ˘n÷ currently equals ˘1÷.
Note: If the SG detects loss of the ASP1 M2UA peer (M2UA heartbeat loss - Find the SCTP association to the chosen SG
or detection of SCTP failure), the first SG-ASP1 ASP Inactive message
exchange would not occur.
5.3 SG to MGC, MTP Level 2 to MTP Level 3 Boundary Procedures - Determine the correct stream in the SCTP association based on
the SS7 link
- Fill in the MAUP message, fill in M2UA Message Header, fill in
Common Header
- Send the MAUP message to the remote M2UA peer in the SG, over the
SCTP association
When the M2UA layer on the SG has a MAUP message to send to the ASP, it
will do the following:
- Determine the AS for the Interface Identifier
- Determine the Active ASP (SCTP association) within the AS
- Determine the correct stream in the SCTP association based on
the SS7 link
- Fill in the MAUP message, fill in M2UA Message Header, fill in
Common Header
- Send the MAUP message to the remote M2UA peer in the ASP, over the
SCTP association
5.3.1 SS7 Link Alignment 5.3.1 SS7 Link Alignment
The MGC can request that a SS7 link be brought into alignment using the The MGC can request that a SS7 link be brought into alignment using the
normal or emergency procedure. An example of the message flow to bring normal or emergency procedure. An example of the message flow to bring
a SS7 link in-service using the normal alignment procedure is shown a SS7 link in-service using the normal alignment procedure is shown
below. below.
SG ASP SG ASP
| | | |
skipping to change at page 31, line 29 skipping to change at page 31, line 29
| | | |
|-----------Retrieval Cfm------------>| |-----------Retrieval Cfm------------>|
| | | |
|-----------Retrieval Ind------------>| |-----------Retrieval Ind------------>|
|-----------Retrieval Ind------------>| |-----------Retrieval Ind------------>|
|-------Retrieval Complete Ind------->| |-------Retrieval Complete Ind------->|
| | | |
Note: The number of Retrieval Indication is dependent on the number of Note: The number of Retrieval Indication is dependent on the number of
messages in the retransmit queue that have been requested. Only one messages in the retransmit queue that have been requested. Only one
Retrieval Complete Indication should be sent. Retrieval Complete Indication SHOULD be sent.
6.0 Security 6.0 Security
6.1 Introduction
M2UA is designed to carry signaling messages for telephony services. As such, M2UA is designed to carry signaling messages for telephony services. As such,
M2UA must involve the security needs of several parties: the end users M2UA MUST involve the security needs of several parties: the end users
of the services; the network providers and the applications involved. of the services; the network providers and the applications involved.
Additional requirements may come from local regulation. While having some Additional requirements MAY come from local regulation. While having some
overlapping security needs, any security solution should fulfill all of the overlapping security needs, any security solution SHOULD fulfill all of the
different parties' needs. different parties' needs.
6.2 Threats 6.1 Threats
There is no quick fix, one-size-fits-all solution for security. As a There is no quick fix, one-size-fits-all solution for security. As a
transport protocol, M2UA has the following security objectives: transport protocol, M2UA has the following security objectives:
* Availability of reliable and timely user data transport. * Availability of reliable and timely user data transport.
* Integrity of user data transport. * Integrity of user data transport.
* Confidentiality of user data. * Confidentiality of user data.
M2UA runs on top of SCTP. SCTP [6] provides certain transport related M2UA runs on top of SCTP. SCTP [5] provides certain transport related
security features, such as: security features, such as:
* Blind Denial of Service Attacks * Blind Denial of Service Attacks
* Flooding * Flooding
* Masquerade * Masquerade
* Improper Monopolization of Services * Improper Monopolization of Services
When M2UA is running in professionally managed corporate or service When M2UA is running in professionally managed corporate or service
provider network, it is reasonable to expect that this network includes provider network, it is reasonable to expect that this network includes
an appropriate security policy framework. The "Site Security Handbook" [9] an appropriate security policy framework. The "Site Security Handbook" [8]
should be consulted for guidance. SHOULD be consulted for guidance.
When the network in which M2UA runs in involves more than one party, it When the network in which M2UA runs in involves more than one party, it
may not be reasonable to expect that all parties have implemented security MAY NOT be reasonable to expect that all parties have implemented security
in a sufficient manner. In such a case, it is recommended that IPSEC is in a sufficient manner. In such a case, it is recommended that IPSEC is
used to ensure confidentiality of user payload. Consult [10] for more used to ensure confidentiality of user payload. Consult [9] for more
information on configuring IPSEC services. information on configuring IPSEC services.
6.3 Protecting Confidentiality 6.2 Protecting Confidentiality
Particularly for mobile users, the requirement for confidentiality may Particularly for mobile users, the requirement for confidentiality MAY
include the masking of IP addresses and ports. In this case application include the masking of IP addresses and ports. In this case application
level encryption is not sufficient; IPSEC ESP should be used instead. level encryption is not sufficient; IPSEC ESP SHOULD be used instead.
Regardless of which level performs the encryption, the IPSEC ISAKMP Regardless of which level performs the encryption, the IPSEC ISAKMP
service should be used for key management. service SHOULD be used for key management.
7.0 IANA Considerations 7.0 IANA Considerations
A request will be made to IANA to assign an M2UA value for the Payload A request will be made to IANA to assign an M2UA value for the Payload
Protocol Identifier in SCTP Payload Data chunk. The following SCTP Payload Protocol Identifier in SCTP Payload Data chunk. The following SCTP Payload
Protocol Identifier will be registered: Protocol Identifier will be registered:
M2UA tbd M2UA 0x10
The SCTP Payload Protocol Identifier is included in each SCTP Data chunk, The SCTP Payload Protocol Identifier is included in each SCTP Data chunk,
to indicate which protocol the SCTP is carrying. This Payload Protocol to indicate which protocol the SCTP is carrying. This Payload Protocol
Identifier is not directly used by SCTP but may be used by certain network Identifier is not directly used by SCTP but MAY be used by certain network
entities to identify the type of information being carried in a Data chunk. entities to identify the type of information being carried in a Data chunk.
The User Adaptation peer may use the Payload Protocol Identifier as a way The User Adaptation peer MAY use the Payload Protocol Identifier as a way
of determining additional information about the data being presented to it of determining additional information about the data being presented to it
by SCTP. by SCTP.
8.0 Acknowledgements 8.0 Acknowledgements
The authors would like to thank Ian Rytina, Hanns Juergen Schwarzbauer The authors would like to thank John Loughney, Neil Olson, Michael
and ZhangYi for their valuable comments and suggestions. Tuexen, Nikhil Jain, Steve Lorusso, Dan Brendes, Joe Keller, Heinz
Prantner, Barry Nagelberg, Naoto Makinae for their valuable comments
and suggestions.
9.0 References 9.0 References
[1] ITU-T Recommendation Q.700, 'Introduction To ITU-T Signalling [1] ITU-T Recommendation Q.700, 'Introduction To ITU-T Signalling
System No. 7 (SS7)' System No. 7 (SS7)'
[2] ITU-T Recommendation Q.701-Q.705, 'Signalling System No. 7 (SS7) - [2] ITU-T Recommendation Q.701-Q.705, 'Signalling System No. 7 (SS7) -
Message Transfer Part (MTP)' Message Transfer Part (MTP)'
[3] ANSI T1.111 'Signalling System Number 7 - Message Transfer Part' [3] ANSI T1.111 'Signalling System Number 7 - Message Transfer Part'
[4] Bellcore GR-246-CORE 'Bell Communications Research Specification [4] Bellcore GR-246-CORE 'Bell Communications Research Specification
of Signaling System Number 7', Volume 1, December 1995 of Signaling System Number 7', Volume 1, December 1995
[5] Framework Architecture for Signaling Transport, draft-ietf-sigtran- [5] Stream Control Transmission Protocol, RFC 2960, October 2000
framework-arch-03.txt, June 1999
[6] Simple Control Transmission Protocol, draft-ietf-sigtran-sctp-07.txt,
March 2000
[7] Media Gateway Control Protocol (MGCP), draft-huitema-megaco-mgcp- [6] Architectural Framework for Signaling Transport, RFC 2719 ,
v1-03.txt, August 1999 October 1999
[8] ITU-T Recommendation Q.2210, 'Message transfer part level 3 [7] ITU-T Recommendation Q.2210, 'Message transfer part level 3
functions and messages using the services of ITU-T functions and messages using the services of ITU-T
Recommendation Q.2140' Recommendation Q.2140'
[9] RFC 2196, "Site Security Handbook", B. Fraser Ed., September 1997 [8] Site Security Handbook, RFC 2196, September 1997
[10] RFC 2401, "Security Architecture for the Internet Protocol", S. [9] Security Architecture for the Internet Protocol, RFC 2401
Kent, R. Atkinson, November 1998.
10.0 Author's Addresses 10.0 Author's Addresses
Ken Morneault Tel: +1-703-484-3323 Ken Morneault Tel: +1-703-484-3323
Cisco Systems Inc. EMail: kmorneau@cisco.com Cisco Systems Inc. EMail: kmorneau@cisco.com
13615 Dulles Technology Drive 13615 Dulles Technology Drive
Herndon, VA. 20171 Herndon, VA. 20171
USA USA
Ram Dantu, Ph.D. Tel +1-469-255-0716
Cisco Systems EMail rdantu@cisco.com
17919 Waterview
Dallas, TX 75252
USA
Malleswar Kalla Tel: +1-973-829-5212 Malleswar Kalla Tel: +1-973-829-5212
Telcordia Technologies EMail: kalla@research.telcordia.com Telcordia Technologies EMail: kalla@research.telcordia.com
MCC 1J211R MCC 1J211R
445 South Street 445 South Street
Morristown, NJ 07960 Morristown, NJ 07960
USA USA
Greg Sidebottom Tel: +1-613-763-7305 Greg Sidebottom Tel: +1-613-763-7305
Nortel Networks EMail: gregside@nortelnetworks.com Nortel Networks EMail: gregside@nortelnetworks.com
3685 Richmond Rd, 3685 Richmond Rd,
Nepean, Ontario Nepean, Ontario
Canada K2H5B7 Canada K2H5B7
Ram Dantu, Ph.D. Tel +1-972-234-6070 extension 211
IPmobile EMail rdantu@ipmobile.com
1651 North Glenville, Suite 216
Richardson, TX 75081
USA
Tom George Tel: +1-972-519-3168 Tom George Tel: +1-972-519-3168
Alcatel USA EMail: tom.george@usa.alcatel.com Alcatel USA EMail: tom.george@usa.alcatel.com
1000 Coit Road 1000 Coit Road
Plano, TX 74075 Plano, TX 74075
USA USA
This Internet Draft expires December 2000. This Internet Draft expires April 2001.
 End of changes. 

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