draft-ietf-sigtran-signalling-over-sctp-applic-04.txt   draft-ietf-sigtran-signalling-over-sctp-applic-05.txt 
INTERNET-DRAFT L. Coene(Ed) INTERNET-DRAFT L. Coene(Ed)
Internet Engineering Task Force Siemens Internet Engineering Task Force Siemens
Issued: February 2002 J. Pastor Issued: April 2002 J. Pastor
Expires: August 2002 Ericsson Expires: September 2002 Ericsson
Telephony Signalling Transport over SCTP applicability statement Telephony Signalling Transport over SCTP applicability statement
<draft-ietf-sigtran-signalling-over-sctp-applic-04.txt> <draft-ietf-sigtran-signalling-over-sctp-applic-05.txt>
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. Internet-Drafts are working all provisions of Section 10 of RFC2026. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas, documents of the Internet Engineering Task Force (IETF), its areas,
and its working groups. Note that other groups may also distribute and its working groups. Note that other groups may also distribute
working documents as Internet-Drafts. working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six Internet-Drafts are draft documents valid for a maximum of six
skipping to change at page 1, line 32 skipping to change at page 1, line 32
reference material or to cite them other than as "work in progress." reference material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
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Abstract Abstract
This document describes the applicability of the Stream Control This document describes the applicability of the new protocols
Transmission Protocol (SCTP)[RFC2960] for transport of telephony developed under the signaling transport framework[RFC2719]. A
signalling information over IP infrastructure. Special description of the main issues regarding the use of the Stream
considerations for using SCTP to meet the requirements of Control Transmission Protocol (SCTP)[RFC2960] and each adaptation
transporting telephony signalling [RFC2719] are discussed. layer for transport of telephony signalling information over IP
infrastructure is explained.
Draft Telephony UAL AS March 2002 Draft Telephony Signalling AS April 2002
Table of contents Table of contents
Telephony signalling over SCTP Applicability statement ......... ii Telephony signalling over SCTP Applicability statement ......... ii
Chapter 1: Introduction ........................................ 2 Chapter 1: Introduction ........................................ 2
Chapter 1.1: Terminology ....................................... 2 Chapter 1.1: Scope ..... ....................................... 3
Chapter 1.2: Contributors ...................................... 3 Chapter 1.2: Terminology ....................................... 3
Chapter 1.3: Overview ......................................... 3 Chapter 1.3: Contributors ...................................... 3
Chapter 2: Applicability of telephony signalling transport Chapter 2: SIGTRAN architecture ................................ 4
using SCTP ..................................................... 4 Chapter 2.1: Overview ......................................... 4
Chapter 3: Issues for transporting Telephony signalling Chapter 3: Issues for transporting Telephony signalling
information over SCTP .......................................... 4 information over SCTP .......................................... 6
Chapter 3.1: Congestion control ................................ 4 Chapter 3.1: Congestion control ................................ 6
Chapter 3.2: Detection of failures ............................. 5 Chapter 3.2: Detection of failures ............................. 6
Chapter 3.2.1: Retransmission TimeOut (RTO) calculation ........ 5 Chapter 3.2.1: Retransmission TimeOut (RTO) calculation ........ 7
Chapter 3.2.2: Heartbeat ....................................... 5 Chapter 3.2.2: Heartbeat ....................................... 7
Chapter 3.2.3: Maximum Number of retransmissions ............... 5 Chapter 3.2.3: Maximum Number of retransmissions ............... 7
Chapter 3.3: Shorten end-to-end message delay ................. 6 Chapter 3.3: Shorten end-to-end message delay ................. 7
Chapter 3.4: Bundling considerations ........................... 6 Chapter 3.4: Bundling considerations ........................... 8
Chapter 3.5: Stream Usage ...................................... 6 Chapter 3.5: Stream Usage ...................................... 8
Chapter 4: User Adaptation Layers............................... 6 Chapter 4: User Adaptation Layers............................... 8
Chapter 4.1: IUA (ISDN Q.921 User Adaptation). ................. 7 Chapter 4.1: IUA (ISDN Q.921 User Adaptation) .................. 10
Chapter 4.2: V5UA (V5.2-User Adaptation) Layer.................. 8 Chapter 4.2: V5UA (V5.2-User Adaptation) Layer ................. 11
Chapter 4.3: M2UA (SS7 MTP2 User Adaptation) Layer.............. 8 Chapter 4.3: DUA (DPNSS/DASS User adaptation) Layer ............ 12
Chapter 4.4: M2PA (SS7 MTP2-User Peer-to-Peer Adaptation) Layer. 9 Chapter 4.4: M2UA (SS7 MTP2 User Adaptation) Layer ............. 12
Chapter 4.5: M3UA (SS7 MTP3 User Adaptation) Layer.............. 11 Chapter 4.5: M2PA (SS7 MTP2-User Peer-to-Peer Adaptation) Layer. 13
Chapter 4.6: SUA (SS7 SCCP User Adaptation) Layer............... 11 Chapter 4.6: M3UA (SS7 MTP3 User Adaptation) Layer ............. 15
Chapter 5: Security considerations ............................. 12 Chapter 4.7: SUA (SS7 SCCP User Adaptation) Layer .............. 16
Chapter 6: References and related work ......................... 13 Chapter 5: Security considerations ............................. 18
Chapter 7: Acknowledgments ..................................... 13 Chapter 6: References and related work ......................... 18
Chapter 8: Author's address .................................... 14 Chapter 7: Acknowledgments ..................................... 19
Chapter 8: Author's address .................................... 19
1 INTRODUCTION 1 INTRODUCTION
Transport of telephony signalling requires special This document intends to inform how to transport telephony
considerations. In order to use SCTP, special care must be taken to signalling protocols, used in classic telephony systems, over IP
meet the performance, timing and failure management requirements. networks. The whole architecture is called SIGTRAN (Signalling
Draft Telephony UAL AS March 2002 Draft Telephony Signalling AS April 2002
1.1 Terminology Transport) as described in RFC2719 and is composed of a transport
protocol(SCTP) and several User Adaptation (UAL) layers. The
transport protocol SCTP has been been developed to fulfill the
stringent requirements that telephony signalling networks have. The
set of User Adaptation layers have also been introduced to make it
possible that different signalling protocols can use the SCTP layer.
1.1 Scope
The scope of this document is to explain the way that user
adaptation layers and SCTP protocols have to be used to transport
Telephony signalling information over IP.
1.2 Terminology
The following terms are commonly identified in related work: The following terms are commonly identified in related work:
Association: SCTP connection between two endpoints. Association: SCTP connection between two endpoints.
Stream: A uni-directional logical channel established within an Stream: A uni-directional logical channel established within an
association, within which all user messages are delivered in association, within which all user messages are delivered in
sequence except for those submitted to the unordered delivery sequence except for those submitted to the unordered delivery
service. service.
1.2 Contributors SPU: Signalling protocol user, the application on top of the User
adaptation layer.
The following people contributed to the document: L. Coene(Editor),
M. Tuexen, G. Verwimp, J. Loughney, R.R. Stewart, Qiaobing Xie,
M. Holdrege, M.C. Belinchon, A. Jungmaier, J. Pastor and L. Ong.
1.3 Overview
SCTP provides a general purpose, reliable transport between two
endpoints.
The following functions are provided by SCTP:
- Reliable Data Transfer
- Multiple streams to help avoid head-of-line blocking CTSP: Classical Telephony Signalling protocol(examples: MTP level2,
MTP level 3, SCCP....).
- Ordered and unordered data delivery on a per-stream basis UAL: User adaptation layer: the protocol that encapsulate the upper
layer telephony signalling protocols that are to be transported over
SCTP/IP.
- Bundling and fragmentation of user data ISEP: IP signalling endpoint: a IP node that implements SCTP and a
User adapatation layer.
- Congestion and flow control SP: signalling point
- Support continuous monitoring of reachability 1.3 Contributors
- Graceful termination of association The following people contributed to the document: L. Coene(Editor),
M. Tuexen, G. Verwimp, J. Loughney, R.R. Stewart, Qiaobing Xie,
M. Holdrege, M.C. Belinchon, A. Jungmaier, J. Pastor and L. Ong.
- Support of multi-homing for added reliability Draft Telephony Signalling AS April 2002
- Protection against blind denial-of-service attacks 2 SIGTRAN architecture
- Protection against blind masquerade attacks The SIGTRAN architecture describes the transport of signalling
information over IP infrastructure.
Telephony Signalling transport over IP normally uses the following Telephony Signalling transport over IP normally uses the following
Draft Telephony UAL AS March 2002
architecture: architecture:
Telephony Application Telephony Signalling Application
| |
+------------------------------------+ +------------------------------------+
| Signalling Adaptation module | | Signalling Adaptation Layers |
+------------------------------------+ +------------------------------------+
| |
+------------------------------------+ +------------------------------------+
|Stream Control Transmission Protocol| |Stream Control Transmission Protocol|
| (SCTP) | | (SCTP) |
+------------------------------------+ +------------------------------------+
| |
Internet Protocol (IPv4/IPv6) Internet Protocol (IPv4/IPv6)
Figure 1.1: Telephony signalling transport protocol stack Figure 1.1: Telephony signalling transport protocol stack
skipping to change at page 4, line 36 skipping to change at page 4, line 42
(1) Adaptation modules are used when the telephony application needs (1) Adaptation modules are used when the telephony application needs
to preserve an existing primitive interface. (e.g. management to preserve an existing primitive interface. (e.g. management
indications, data operation primitives, ... for a particular indications, data operation primitives, ... for a particular
user/application protocol). user/application protocol).
(2) SCTP, specially configured to meet the telephony application (2) SCTP, specially configured to meet the telephony application
performance requirements. performance requirements.
(3) The standard Internet Protocol. (3) The standard Internet Protocol.
2 Applicability of Telephony Signalling transport using SCTP The telephony signalling protocols to be transported can be:
SCTP can be used as the transport protocol for telephony - SS7 MTP3 users: SCCP, ISUP, TUP...
- SS7 MTP2 users: MTP3
- SS7 SCCP users: RANAP, MAP(+TCAP), INAP(+TCAP)...
- ISDN Q.921 users: Q.931
- V5.2/DSS1
- ....
Draft Telephony Signalling AS April 2002
Every classic telephony protocol can have a corresponding UAL
developed.
The user adaptation layers(UALs) are a set of protocols that
encapsulate a specific signalling protocol to be transported over
SCTP. The adapation is done in a way that the upper signalling
protocols that are relayed remain unaware that the lower layers are
different to the originail lower telephony signalling layers. In
that sense, the upper interface of the user adapatation layers need
to be the same as the upper layer interface to its original lower
layer. If a MTP user is being relayed over the IP network, the
related UAL used to transport the MTP user will have the same upper
interface as MTP has.
The Stream Control Transmission protocol was designed to fulfill the
stringent transport requirements that classical signalling protocols
have and is therefore the recommended transport protocol to use for
this purpose.
The following functions are provided by SCTP:
- Reliable Data Transfer
- Multiple streams to help avoid head-of-line blocking
- Ordered and unordered data delivery on a per-stream basis
- Bundling and fragmentation of user data
- Congestion and flow control
- Support continuous monitoring of reachability
- Graceful termination of association
- Support of multi-homing for added reliability
- Protection against blind denial-of-service attacks
- Protection against blind masquerade attacks
SCTP is used as the transport protocol for telephony signalling
applications. Message boundaries are preserved during data applications. Message boundaries are preserved during data
transport and so no message delineation is needed. The user data can transport by SCTP and so each UA can specify its own message
be delivered by the order of transmission within a stream(in structure withing the SCTP user data. The SCTP user data can be
sequence delivery) or the order of arrival. delivered by the order of transmission within a stream(in sequence
delivery) or unordered.
SCTP can be used to provide redundancy and fault tolerance at the SCTP can be used to provide redundancy at the
transport layer and below. Telephony applications needing this level transport layer and below. Telephony applications needing this level
of fault tolerance can make use of SCTP's multi-homing support. of redundancy can make use of SCTP's multi-homing support.
Draft Telephony Signalling AS April 2002
SCTP can be used for telephony applications where head-of-line SCTP can be used for telephony applications where head-of-line
blocking is a concern. Such an application should use multiple blocking is a concern. Such an application should use multiple
streams to provide independent ordering of telephony signalling streams to provide independent ordering of telephony signalling
messages. messages.
3 Issues for transporting telephony signalling over SCTP 3 Issues for transporting telephony signalling over SCTP
Draft Telephony UAL AS March 2002 Transport of telephony signalling requires special
considerations. In order to use SCTP, special care must be taken to
meet the performance, timing and failure management requirements.
3.1 Congestion Control 3.1 Congestion Control
The basic mechanism of congestion control in SCTP have been The basic mechanism of congestion control in SCTP have been
described in [RFC2960]. SCTP congestion control sometimes conflicts described in [RFC2960]. SCTP congestion control sometimes conflicts
with the timing requirements of telephony signalling transport. with the timing requirements of telephony signalling application
messages which are transported by SCTP. During congestion, messages
may be delayed by SCTP, thus sometimes violating the timing
requirements of those telephony applications.
In an engineered network (e.g. a private intranet), in which network In an engineered network (e.g. a private intranet), in which network
capacity and maximum traffic is very well understood, some telephony capacity and maximum traffic are very well understood, some
signalling applications may choose to relax the congestion control telephony signalling applications may choose to relax the congestion
rules in order to satisfy the timing requirements. But this should control rules of SCTP in order to satisfy the timing
be done without destabilising the network, otherwise this would lead requirements. In order to do this, they should employ their own
to potential congestion collapse of the network. congestion control mechanisms. But this should be done without
destabilising the network, otherwise this would lead to potential
congestion collapse of the network.
Some telephony signalling applications may have their own congestion Some telephony signalling applications may have their own congestion
control and flow control techniques. These techniques may interact control and flow control techniques. These techniques may interact
with the congestion control procedures in SCTP. Additionally, with the congestion control procedures in SCTP.
telephony applications may use SCTP stream based flow control
[SCTPFLOW].
3.2 Detection of failures 3.2 Detection of failures
Telephony systems often must achieve high availability in operation. Telephony systems often must have no single point of failure in
For example, they are often required to be able to preserve stable operation.
calls during a component failure. Therefore error situations at the
transport layer and below must be detected very fast so that the The UA must meet certain service availability and performance
application can take approriate steps to recover and preserve the requirements according to the classical signalling layers they are
stable calls. This poses special requirements on SCTP to discover replacing. Those requirements may be specific for each UA.
For example, telephony systems are often required to be able to
preserve stable calls during a component failure. Therefore error
situations at the transport layer and below must be detected quickly
Draft Telephony Signalling AS April 2002
so that the UA can take approriate steps to recover and preserve the
calls. This poses special requirements on SCTP to discover
unreachablility of a destination address or a peer. unreachablility of a destination address or a peer.
3.2.1 Retransmission TimeOut (RTO) calculation 3.2.1 Retransmission TimeOut (RTO) calculation
The SCTP protocol parameter RTO.Min value has a direct impact on the The SCTP protocol parameter RTO.Min value has a direct impact on the
calculation of the RTO itself. Some telephony applications want to calculation of the RTO itself. Some telephony applications want to
lower the value of the RTO.Min to less than 1 second. This would lower the value of the RTO.Min to less than 1 second. This would
allow the message sender to reach the maximum allow the message sender to reach the maximum
number-of-retransmission threshold faster in the case of network number-of-retransmission threshold faster in the case of network
failures. However, lowering RTO.Min may have a negative impact on failures. However, lowering RTO.Min may have a negative impact on
network behaviour [ALLMAN99]. network behaviour [ALLMAN99].
In some rare cases, telephony applications might not want to use the In some rare cases, telephony applications might not want to use the
exponential timer back-off concept in RTO calculation in order to exponential timer back-off concept in RTO calculation in order to
speed up failure detection. The danger of doing this is that, when speed up failure detection. The danger of doing this is that, when
network congestion occurs, not backing off the timer may worsen the network congestion occurs, not backing off the timer may worsen the
congestion situation. Therefore, this strategy should never be used congestion situation. Therefore, this strategy should never be used
in public Internet. in public Internet.
It should be noted that not using delayed SACK will also help faster It should be noted that not using delayed SACK will also help faster
Draft Telephony UAL AS March 2002
failure detection. failure detection.
3.2.2 Heartbeat 3.2.2 Heartbeat
For faster detection of (un)availability of idle paths, the For faster detection of (un)availability of idle paths, the
telephony application may consider lowering the SCTP parameter telephony application may consider lowering the SCTP parameter
HB.interval. It should be noted this will result in a higher traffic HB.interval. It should be noted this might result in a higher traffic
load. load.
3.2.3 Maximum number of retransmissions 3.2.3 Maximum number of retransmissions
Setting Path.Max.Retrans and Association.Max.Retrans SCTP parameters Setting Path.Max.Retrans and Association.Max.Retrans SCTP parameters
to lower values will speed up both destination address and peer to lower values will speed up both destination address and peer
failure detection. However, if these values are set too low, the failure detection. However, if these values are set too low, the
probability of false detections will increase. probability of false fault detections might increase.
3.3 Shorten end-to-end message delay 3.3 Shorten end-to-end message delay
Telephony applications often require short end-to-end message Telephony applications often require short end-to-end message
delays. The methods described in section 3.2.1 on lowering RTO and delays. The method described in section 3.2.1 on lowering RTO may
not using delayed SACK may be considered.
Draft Telephony Signalling AS April 2002
be considered. The different paths within a single association will
have a different RTO, so using the path with the lowest RTO will
lead to a shorter end-to-end message delay for the application
running on top of the UA's.
3.4 Bundling considerations 3.4 Bundling considerations
Bundling small telephony signalling messages at transmission helps Bundling small telephony signalling messages at transmission helps
improve the bandwidth usage efficiency of the network. On the improve the bandwidth usage efficiency of the network. On the
downside, bundling may introduce additional delay to some of the downside, bundling may introduce additional delay to some of the
messages. This should be taken into consideration when end-to-end messages. This should be taken into consideration when end-to-end
delay is a concern. delay is a concern.
3.5 Stream Usage 3.5 Stream Usage
Telephony signalling traffic is often composed of multiple, Telephony signalling traffic is often composed of multiple,
independent message sequences. It is highly desirable to transfer independent message sequences. It is highly desirable to transfer
those independent message sequences in separate SCTP streams. This those independent message sequences in separate SCTP streams. This
reduces the probability of head-of-line blocking in which the reduces the probability of head-of-line blocking in which the
retransmission of a lost message affects the delivery of other retransmission of a lost message affects the delivery of other
messages not belonging to the same message sequence. messages not belonging to the same message sequence.
4 User Adaptation Layers 4 User Adaptation Layers
Draft Telephony UAL AS March 2002 Users Adaptation Layers have been defined to encapsulate different
signalling protocols in order to transport them over SCTP/IP.
Users Adaptation Layers are defined to substitute the telephony
signaling protocol that is below of the telephony signaling protocol
to be relayed.
There are UALs for both access signaling (DSS1) and trunk signaling There are UALs for both access signalling (DSS1) and trunk signalling
(SS7). A brief description of the standardized UALs follows in the (SS7). A brief description of the standardized UALs follows in the
next sub-sections. next sub-sections.
The delivery mechanism in the several UALs The delivery mechanism in the several UALs
- Support seamless operation of UALs user peers over an IP network - Supports seamless operation of UALs user peers over an IP network
connection. connection.
- Support the interface boundary that the UAL user had with the - Supports the interface boundary that the UAL user had with the
traditional lower layer. traditional lower layer.
- Support management of SCTP transport associations and traffic - Supports management of SCTP transport associations and traffic
between SGs and ISEPs or two ISEPs between SGs and ISEPs or two ISEPs
- Support asynchronous reporting of status changes to management. - Supports asynchronous reporting of status changes to management.
Two main scenarios have been developed for Signaling Transport: Draft Telephony Signalling AS April 2002
- Intercommunication of traditional Signaling transport nodes and IP Two main scenarios have been developed for Signalling Transport:
- Intercommunication of traditional Signalling transport nodes and IP
based nodes. based nodes.
Traditional Telephony Traditional Telephony
Telephony Signaling Telephony Signalling
******* Signaling ********** over IP ******** ******* Signalling ********** over IP ********
* SEP *----------------* SG *--------------* ISEP * * SEP *----------------* SG *--------------* ISEP *
******* ********** ******** ******* ********** ********
+-----+ +------+ +-----+ +------+
| SP | | SP | | SPU | | SPU |
+-----+ +----+----+ +------+ +-----+ +----+----+ +------+
| | | |UAL | | UAL | | | | |UAL | | UAL |
| | | +----+ +------+ | | | +----+ +------+
|TTST | |TTST|SCTP| | SCTP | |CTSP | |CTSP|SCTP| | SCTP |
| | | +----+ +------+ | | | +----+ +------+
| | | | IP | | IP | | | | | IP | | IP |
+-----+ +---------+ +------+ +-----+ +---------+ +------+
SEP: Signaling Endpoint SEP: Signalling Endpoint
SG: Signaling Gateway SG: Signalling Gateway
ISEP: IP Signaling Endpoint ISEP: IP Signalling Endpoint
SP: Signaling Protocol SPU: Signalling Protocol User
TTST: Traditional Telephony Signaling Transport CTSP: Classical Telephony Signalling Protocol
UAL: User Adaptation Layer UAL: User Adaptation Layer
SCTP: Stream Control Transport Protocol SCTP: Stream Control Transport Protocol
Draft Telephony UAL AS March 2002 It is also referred as SG to AS communication. AS is the name that
It is also referred as SG to AS communication. AS I the name that
UAL usually gives to the ISEP nodes. It stands for Application UAL usually gives to the ISEP nodes. It stands for Application
Server. Server.
Draft Telephony Signalling AS April 2002
- Communication inside the IP networks. - Communication inside the IP networks.
Telephony Telephony
Signaling Signalling
******** over IP ******** ******** over IP ********
* ISEP *------------------* ISEP * * ISEP *------------------* ISEP *
******** ******** ******** ********
+------+ +------+ +------+ +------+
| SP | | SP | | SPU | | SPU |
+------+ +------+ +------+ +------+
| UAL | | UAL | | UAL | | UAL |
+------+ +------+ +------+ +------+
| SCTP | | SCTP | | SCTP | | SCTP |
+------+ +------+ +------+ +------+
| IP | | IP | | IP | | IP |
+------+ +------+ +------+ +------+
It is also referred as IPSP communication. IPSP is the name of the This is also referred to as IPSP communication. IPSP is the name
role that an IP-based node plays UAL usually gives to the ISEP given to the role that a UAL plays on an IP-based node. It stands
nodes. It stands for IP Signaling Point. for IP Signalling Point.
4.1 IUA (ISDN Q.921 User Adaptation) 4.1 IUA (ISDN Q.921 User Adaptation)
This document supports both ISDN Primary Rate Access (PRA) as well as This protocol supports both ISDN Primary Rate Access (PRA) as well
Basic Rate Access (BRA) including the support for both point-to-point as Basic Rate Access (BRA) including the support for both
and point-to-multipoint modes of communication. This support point-to-point and point-to-multipoint modes of communication. This
includes Facility Associated Signaling (FAS), Non-Facility Associated support includes Facility Associated Signalling (FAS), Non-Facility
Signaling (NFAS) and NFAS with backup D channel. Associated Signalling (NFAS) and NFAS with backup D channel.
It implements the client/server architecture. The default orientation It implements the client/server architecture. The default
would be for the SG to take on the role of server while the ISEP is orientation is for the SG to take on the role of server while the
the client. The SCTP (and UDP/TCP) Registered User Port Number ISEP is the client. The SCTP (and UDP/TCP) Registered User Port
Assignment for IUA is 9900. Number Assignment for IUA is 9900.
Examples of the upper layers to be transported would be Q.931 and Examples of the upper layers to be transported are Q.931 and QSIG.
QSIG.
The main scenario supported by this UAL is the SG to ISEP The main scenario supported by this UAL is the SG to ISEP
communication where the ISEP role is typically played by a node communication where the ISEP role is typically played by a node
called MGC defined in [RFC2719]. called an MGC, as defined in [RFC2719].
Draft Telephony UAL AS March 2002 Draft Telephony Signalling AS April 2002
****** ISDN ****** IP ******* ****** ISDN ****** IP *******
* EP *---------------* SG *--------------* MGC * * EP *---------------* SG *--------------* MGC *
****** ****** ******* ****** ****** *******
+-----+ +-----+ +-----+ +-----+
|Q.931| (NIF) |Q.931| |Q.931| (NIF) |Q.931|
+-----+ +----------+ +-----+ +-----+ +----------+ +-----+
| | | | IUA| | IUA | | | | | IUA| | IUA |
| | | +----+ +-----+ | | | +----+ +-----+
|Q.921| |Q.921|SCTP| |SCTP | |Q.921| |Q.921|SCTP| |SCTP |
| | | +----+ +-----+ | | | +----+ +-----+
| | | | IP | | IP | | | | | IP | | IP |
+-----+ +-----+----+ +-----+ +-----+ +-----+----+ +-----+
NIF - Nodal Interworking Function NIF - Nodal Interworking Function
EP - ISDN End Point EP - ISDN End Point
SCTP - Stream Control Transmission Protocol SCTP - Stream Control Transmission Protocol
IUA - ISDN User Adaptation Layer Protocol IUA - ISDN User Adaptation Layer Protocol
The SCTP (and UDP/TCP) Registered User Port Number Assignment for IUA The SCTP (and UDP/TCP) Registered User Port Number Assignment for
is 9900. IUA is 9900.
The value assigned by IANA for the Payload Protocol Identifier in the The value assigned by IANA for the Payload Protocol Identifier in
SCTP Payload Data chunk is 1 the SCTP Payload Data chunk is "1".
4.2 V5UA (V5.2-User Adaptation) Layer 4.2 V5UA (V5.2-User Adaptation) Layer
It is an extension from the IUA layer with the modifications needed It is an extension from the IUA layer with the modifications needed
to support the differences between Q.921 / Q.931, and V5.2 layer 2 / to support the differences between Q.921 / Q.931, and V5.2 layer 2 /
layer 3. It supports analog telephone access, ISDN basic rate access layer 3. It supports analog telephone access, ISDN basic rate access
and ISDN primary rate access over a V5.2 interface. It is basically and ISDN primary rate access over a V5.2 interface. It is typically
implemented in an interworking scenario with SG. implemented in an interworking scenario with SG.
****** V5.2 ****** IP ******* ****** V5.2 ****** IP *******
* AN *---------------* SG *--------------* MGC * * AN *---------------* SG *--------------* MGC *
****** ****** ******* ****** ****** *******
+-----+ +-----+ +-----+ +-----+
|V5.2 | (NIF) |V5.2 | |V5.2 | (NIF) |V5.2 |
+-----+ +----------+ +-----+ +-----+ +----------+ +-----+
| | | |V5UA| |V5UA | | | | |V5UA| |V5UA |
| | | +----+ +-----+ | | | +----+ +-----+
|LAPV5| |LAPV5|SCTP| |SCTP | |LAPV5| |LAPV5|SCTP| |SCTP |
| | | +----+ +-----+ | | | +----+ +-----+
| | | | IP + | IP | | | | | IP + | IP |
+-----+ +-----+----+ +-----+ +-----+ +-----+----+ +-----+
Draft Telephony UAL AS March 2002 AN - Access Network
NIF - Nodal Interworking Function
AN Access Network Draft Telephony Signalling AS April 2002
NIF Nodal Interworking Function
LAPV5 Link Access Protocol for the V5 channel LAPV5 - Link Access Protocol for the V5 channel
SCTP - Stream Control Transmission Protocol SCTP - Stream Control Transmission Protocol
The SCTP (and UDP/TCP) Registered User Port Number Assignment for The SCTP (and UDP/TCP) Registered User Port Number Assignment for
V5UA is 5675. V5UA is 5675.
The value assigned by IANA for the Payload Protocol Identifier in the The value assigned by IANA for the Payload Protocol Identifier in
SCTP Payload Data chunk is 6 the SCTP Payload Data chunk is "6".
4.3 DUA (DPNSS/DASS 2 User Adaptation) Layer 4.3 DUA (DPNSS/DASS 2 User Adaptation) Layer
The DUA is built on top of IUA defining the necessary extensions to The DUA is built on top of IUA and defines the necessary extensions
IUA for a DPNSS/DASS2 transport. DPNSS stands for Digital Private to IUA for a DPNSS/DASS2 transport. DPNSS stands for Digital Private
Network Signaling System and DASS2 for Digital Access Signaling Network Signalling System and DASS2 for Digital Access Signalling
System No 2 System No 2.
****** DPNSS ****** IP ******* ****** DPNSS ****** IP *******
*PBX *---------------* SG *--------------* MGC * *PBX *---------------* SG *--------------* MGC *
****** ****** ******* ****** ****** *******
+-----+ +-----+ +-----+ +-----+
|DPNSS| (NIF) |DPNSS| |DPNSS| (NIF) |DPNSS|
| L3 | | L3 | | L3 | | L3 |
+-----+ +----------+ +-----+ +-----+ +----------+ +-----+
| | | | DUA| | DUA | | | | | DUA| | DUA |
skipping to change at page 10, line 45 skipping to change at page 12, line 43
| L2 | | L2 |SCTP| |SCTP | | L2 | | L2 |SCTP| |SCTP |
| | | +----+ +-----+ | | | +----+ +-----+
| | | | IP + | IP | | | | | IP + | IP |
+-----+ +-----+----+ +-----+ +-----+ +-----+----+ +-----+
PBX - Private Branch eXchange PBX - Private Branch eXchange
NIF - Nodal Interworking function NIF - Nodal Interworking function
SCTP - Stream Control Transmission Protocol SCTP - Stream Control Transmission Protocol
DUA - DPNSS User Adaptation Layer Protocol DUA - DPNSS User Adaptation Layer Protocol
The value assigned by IANA for the Payload Protocol Identifier in the The value assigned by IANA for the Payload Protocol Identifier in
SCTP Payload Data chunk is TBD. the SCTP Payload Data chunk is "TBD".
4.4 M2UA (SS7 MTP2 User Adaptation) Layer 4.4 M2UA (SS7 MTP2 User Adaptation) Layer
This protocol would be mainly used between a Signaling Gateway (SG) This protocol is typically used between a Signalling Gateway (SG) and
Media Gateway Controler (MGC). The SG will terminate up to MTP Level
Draft Telephony UAL AS March 2002 2 and the MGC will terminate MTP Level 3 and above. In other words,
the SG will transport MTP Level 3 messages over an IP network to a
MGC.
and Media Gateway Controler (MGC). The SG will terminate up to MTP Draft Telephony Signalling AS April 2002
Level 2 and the MGC will terminate MTP Level 3 and above. In other
words, the SG will transport MTP Level 3 messages over an IP network
to a MGC.
The only SS7 MTP2 User is MTP3 that is the protocol transported by MTP3 and MTP3b are the only MTP2 Users that are transported by this
this UAL. UAL.
The SG provides a interworking of transport functions with the IP The SG provides a interworking of transport functions with the IP
transport, in order to transfer the MTP2-User signaling messages to transport, to transfer the MTP2-User signalling messages with MTP2-
and from an Application Server (e.g. MGC) where the peer MTP2- User at an application server(e.g. MGC).
User protocol layer exists.
****** SS7 ****** IP ******* ****** SS7 ****** IP *******
*SEP *-----------* SG *-------------* MGC * *SEP *-----------* SG *-------------* MGC *
****** ****** ******* ****** ****** *******
+----+ +----+ +----+ +----+
|S7UP| |S7UP| |S7UP| |S7UP|
+----+ +----+ +----+ +----+
|MTP + |MTP | |MTP + |MTP |
| L3 | (NIF) |L3 | | L3 | (NIF) |L3 |
+----+ +----+----+ +----+ +----+ +----+----+ +----+
|MTP | |MTP |M2UA| |M2UA| |MTP | |MTP |M2UA| |M2UA|
| | | +----+ +----+ | | | +----+ +----+
| L2 | | L2 |SCTP| |SCTP| | L2 | | L2 |SCTP| |SCTP|
| L1 | | L1 +----+ +----+ | L1 | | L1 +----+ +----+
| | | |IP | |IP | | | | |IP | |IP |
+----+ +---------+ +----+ +----+ +---------+ +----+
MGC - Media Gateway Controler MGC - Media Gateway Controler
SG - Signaling Gateway SG - Signalling Gateway
SEP - SS7 Signaling Endpoint SEP - SS7 Signalling Endpoint
NIF - Nodal Interworking Function NIF - Nodal Interworking Function
IP - Internet Protocol IP - Internet Protocol
SCTP - Stream Control Transmission Protocol SCTP - Stream Control Transmission Protocol
The SCTP (and UDP/TCP) Registered User Port Number Assignment for The SCTP (and UDP/TCP) Registered User Port Number Assignment for
M2UA is 2904. M2UA is 2904.
The value assigned by IANA for the Payload Protocol Identifier in the The value assigned by IANA for the Payload Protocol Identifier in
SCTP Payload Data chunk is 2 the SCTP Payload Data chunk is "2".
4.5 M2PA (SS7 MTP2-User Peer-to-Peer Adaptation) Layer 4.5 M2PA (SS7 MTP2-User Peer-to-Peer Adaptation) Layer
This protocol is used between SS7 Signaling Points employing the MTP This protocol is used between SS7 Signalling Points using the MTP
Level 3 protocol. The SS7 Signaling Points may also employ standard Level 3 protocol. The SS7 Signalling Points may also employ standard
SS7 links using the SS7 MTP Layer 2 to provide transport of MTP Layer SS7 links using the SS7 MTP Level 2 to provide transport of MTP
Level 3 signalling messages.
Draft Telephony UAL AS March 2002
3 signaling messages.
Both configurations: intercommunication of SS7 and IP with SG and Both configurations: interworking of SS7 and IP with SG and
communication between ISEPs are possible. communication between ISEPs are possible.
Draft Telephony Signalling AS April 2002
******** IP ******** ******** IP ********
* IPSP *--------* IPSP * * IPSP *--------* IPSP *
******** ******** ******** ********
+------+ +------+ +------+ +------+
| TCAP | | TCAP | | TCAP | | TCAP |
+------+ +------+ +------+ +------+
| SCCP | | SCCP | | SCCP | | SCCP |
+------+ +------+ +------+ +------+
| MTP3 | | MTP3 | | MTP3 | | MTP3 |
+------+ +------+ +------+ +------+
| M2PA | | M2PA | | M2PA | | M2PA |
+------+ +------+ +------+ +------+
| SCTP | | SCTP | | SCTP | | SCTP |
+------+ +------+ +------+ +------+
| IP | | IP | | IP | | IP |
+------+ +------+ +------+ +------+
IP - Internet Protocol IP - Internet Protocol
IPSP - IP Signaling Point IPSP - IP Signalling Point
SCTP - Stream Control Transmission Protocol SCTP - Stream Control Transmission Protocol
******** SS7 *************** IP ******** ******** SS7 *************** IP ********
* SEP *--------* SG *--------* IPSP * * SEP *--------* SG *--------* IPSP *
******** *************** ******** ******** *************** ********
+------+ +------+ +------+ +------+
| TCAP | | TCAP | | TCAP | | TCAP |
+------+ +------+ +------+ +------+
| SCCP | | SCCP | | SCCP | | SCCP |
+------+ +-------------+ +------+ +------+ +-------------+ +------+
| MTP3 | | MTP3 | | MTP3 | | MTP3 | | MTP3 | | MTP3 |
+------+ +------+------+ +------+ +------+ +------+------+ +------+
| MTP2 | | MTP2 | M2PA | | M2PA | | MTP2 | | MTP2 | M2PA | | M2PA |
+------+ +------+------+ +------+ +------+ +------+------+ +------+
| MTP1 | | MTP1 | SCTP | | SCTP | | MTP1 | | MTP1 | SCTP | | SCTP |
| | | +------+ +------+ | | | +------+ +------+
| | | | IP | | IP | | | | | IP | | IP |
+------+ +------+------+ +------+ +------+ +------+------+ +------+
SEP - SS7 Signaling Endpoint SEP - SS7 Signalling Endpoint
Draft Telephony UAL AS March 2002
These figures are only an example. Other configurations are possible.
For example, IPSPs without traditional SS7 links could use the
protocol layers MTP3/M2PA/SCTP/IP to route SS7 messages in a network
with all IP links.
Another example is that two SGs could be connected over an IP network These figures are only an example. Other configurations are
to form an SG mated pair similar to the way STPs are provisioned in possible.
traditional SS7 networks.
The SCTP (and UDP/TCP) Registered User Port Number Assignment for The SCTP (and UDP/TCP) Registered User Port Number Assignment for
M2PA is TBD. M2PA is TBD.
The value assigned by IANA for the Payload Protocol Identifier in the The value assigned by IANA for the Payload Protocol Identifier in
SCTP Payload Data chunk is TBD the SCTP Payload Data chunk is "5".
Differences between M2PA and M2UA include: Differences between M2PA and M2UA include:
Draft Telephony Signalling AS April 2002
a. M2PA: IPSP processes MTP3/MTP2 primitives. a. M2PA: IPSP processes MTP3/MTP2 primitives.
M2UA: MGC transports MTP3/MTP2 primitives between the SG's MTP2 M2UA: MGC transports MTP3/MTP2 primitives between the SG's MTP2
and the MGC's MTP3 (via the NIF) for processing. and the MGC's MTP3 (via the NIF) for processing.
b. M2PA: SG-IPSP connection is an SS7 link. b. M2PA: SG-IPSP connection is an SS7 link.
M2UA: SG-MGC connection is not an SS7 link. It is an M2UA: SG-MGC connection is not an SS7 link. It is an
extension of MTP to a remote entity. extension of MTP to a remote entity.
c. M2PA: SG is an SS7 node with a point code. c. M2PA: SG is an SS7 node with a point code.
M2UA: SG is not an SS7 node and has no point code. M2UA: SG is not necessarily an SS7 node and may not have a point code.
d. M2PA: SG can have upper SS7 layers, e.g., SCCP. d. M2PA: SG can have upper SS7 layers, e.g., SCCP.
M2UA: SG does not have upper SS7 layers since it has no MTP3. M2UA: SG does not have upper SS7 layers since it has no MTP3.
e. M2PA: relies on MTP3 for management procedures. e. M2PA: relies on MTP3 for management procedures.
M2UA: uses M2UA management procedures. M2UA: uses M2UA management procedures.
4.6 M3UA (SS7 MTP3 User Adaptation) Layer 4.6 M3UA (SS7 MTP3 User Adaptation) Layer
This adaptation layer supports the transport of any SS7 MTP3-User This adaptation layer supports the transport of any SS7 MTP3-User
signaling such as TUP, ISUP and SCCP over IP using the services of signalling such as TUP, ISUP and SCCP over IP using the services of
SCTP. SCTP.
This protocol allows both: This protocol allows both:
- Interconnection of SS7 and IP nodes
- Communication between two IP nodes
Draft Telephony UAL AS March 2002 - Interworking of SS7 and IP nodes
- Communication between two IP nodes
******** SS7 ***************** IP ******** ******** SS7 ***************** IP ********
* SEP *---------* SGP *--------* ASP * * SEP *---------* SGP *--------* ASP *
******** ***************** ******** ******** ***************** ********
+------+ +---------------+ +------+ +------+ +---------------+ +------+
| ISUP | | (NIF) | | ISUP | | ISUP | | (NIF) | | ISUP |
+------+ +------+ +------+ +------+ +------+ +------+ +------+ +------+
| MTP3 | | MTP3 | | M3UA | | M3UA | | MTP3 | | MTP3 | | M3UA | | M3UA |
+------| +------+-+------+ +------+ +------| +------+-+------+ +------+
| MTP2 | | MTP2 | | SCTP | | SCTP | | MTP2 | | MTP2 | | SCTP | | SCTP |
+------+ +------+ +------+ +------+ +------+ +------+ +------+ +------+
| L1 | | L1 | | IP | | IP | | L1 | | L1 | | IP | | IP |
+------+ +------+ +------+ +------+ +------+ +------+ +------+ +------+
SEP - SS7 Signaling End Point SEP - SS7 Signalling End Point
SCTP - Stream Control Transmission Protocol SCTP - Stream Control Transmission Protocol
NIF - Nodal Interworking Function NIF - Nodal Interworking Function
Draft Telephony Signalling AS April 2002
******** IP ******** ******** IP ********
* IPSP *----------* IPSP * * IPSP *----------* IPSP *
******** ******** ******** ********
+------+ +------+ +------+ +------+
|SCCP- | |SCCP- | |SCCP- | |SCCP- |
| User | | User | | User | | User |
+------+ +------+ +------+ +------+
| SCCP | | SCCP | | SCCP | | SCCP |
+------+ +------+ +------+ +------+
| M3UA | | M3UA | | M3UA | | M3UA |
+------+ +------+ +------+ +------+
| SCTP | | SCTP | | SCTP | | SCTP |
+------+ +------+ +------+ +------+
| IP | | IP | | IP | | IP |
+------+ +------+ +------+ +------+
It works using the client-server philosophy. ISEP is recommended to It works using the client-server architecture. It is recommended
be client when talking with a SG. The reserved port by IANA is 2905 that the ISEP act as the client and initiate SCTP associations with
to listen to possible client connections. the SG. The port reserved by IANA is port number 2905. this is the
port upon which the SG should listen for client connections.
The assigned payload protocol identifier for the SCTP DATA chunks is The assigned payload protocol identifier for the SCTP DATA chunks is
3. "3".
4.7 SUA (SS7 SCCP User Adaptation) Layer 4.7 SUA (SS7 SCCP User Adaptation) Layer
This adaptation layer supports the transport of any SS7 SCCP-User This adaptation layer supports the transport of any SS7 SCCP-User
signaling such as MAP, INAP, SMS, BSSAP, RANAP over IP using the signalling such as MAP, INAP, SMS, BSSAP, RANAP over IP using the
services of SCTP. SUA can support only non-call related signaling. services of SCTP.
Draft Telephony UAL AS March 2002
SUA does not pose stringent timing constraints on SCTP due to the For message relaying, SUA should have the same timing constraints as
fact that SUA applications have broad timing requirement (from 10 of SCCP . For the end-to-end approach, SUA applications may have
seconds to hours) which the applications guard themselves and the broader timing requirements (from 100 of milliseconds to hours)
timing supervision of the application is end-to-end, not hop-by- which allows the applications to guard themselves.
hop(as with ISUP).
Possible configurations showed in the pictures below: Possible configurations showed in the pictures below:
- Interconnection of SS7 and IP - Interworking of SS7 and IP
- IP Node to IP Node communication - IP Node to IP Node communication
Draft Telephony Signalling AS April 2002
******** SS7 *************** IP ******** ******** SS7 *************** IP ********
* SEP *---------* *--------* * * SEP *---------* *--------* *
* or * * SG * * ASP * * or * * SG * * ASP *
* STP * * * * * * STP * * * * *
******** *************** ******** ******** *************** ********
+------ +------+ +------ +------+
| SUAP | | SUAP | | SUAP | | SUAP |
+------+ +------+------+ +------+ +------+ +------+------+ +------+
| SCCP | | SCCP | SUA | | SUA | | SCCP | | SCCP | SUA | | SUA |
+------+ +------+------+ +------+ +------+ +------+------+ +------+
| MTP3 | | MTP3 | | | | | MTP3 | | MTP3 | | | |
+------+ +------+ SCTP | | SCTP | +------+ +------+ SCTP | | SCTP |
| MTP2 | | MTP2 | | | | | MTP2 | | MTP2 | | | |
+------+ +------+------+ +------+ +------+ +------+------+ +------+
| L1 | | L1 | IP | | IP | | L1 | | L1 | IP | | IP |
+------+ +------+------+ +------+ +------+ +------+------+ +------+
SUAP - SCCP/SUA User Protocol (TCAP, for example) SUAP - SCCP/SUA User Protocol (TCAP, for example)
STP - SS7 Signaling Transfer Point STP - SS7 Signalling Transfer Point
******** IP ******** ******** IP ********
* *--------* * * *--------* *
* IPSP * * IPSP * * IPSP * * IPSP *
* * * * * * * *
******** ******** ******** ********
+------+ +------+ +------+ +------+
| SUAP | | SUAP | | SUAP | | SUAP |
+------+ +------+ +------+ +------+
| SUA | | SUA | | SUA | | SUA |
+------+ +------+ +------+ +------+
| SCTP | | SCTP | | SCTP | | SCTP |
+------+ +------+ +------+ +------+
| IP | | IP | | IP | | IP |
+------+ +------+ +------+ +------+
Draft Telephony UAL AS March 2002
IANA has registered SCTP Port Number 14001 for SUA. It is IANA has registered SCTP Port Number 14001 for SUA. It is
recommended that SGs use this SCTP port number for listening for new recommended that SGs use this SCTP port number for listening for new
connections. The payload protocol identifier for the SCTP DATA chunks connections. The payload protocol identifier for the SCTP DATA
is 4. chunks is "4".
Draft Telephony Signalling AS April 2002
5 Security considerations 5 Security considerations
UALs are designated to carry signaling messages for telephony UALs are designated to carry signalling messages for telephony
services. As such, UALs must involve the security needs of several services. As such, UALs must involve the security needs of several
parties: the end users of the services; the network providers and parties: the end users of the services; the network providers and
the applications involved. Additional requirements may come from the applications involved. Additional requirements may come from
local regulation. While having some overlapping security needs, any local regulation. While having some overlapping security needs, any
security solution should fulfill all of the different parties' security solution should fulfill all of the different parties'
needs. See specific Security considerations in each UAL technical needs. See specific Security considerations in each UAL technical
specification. specification.
SCTP only tries to increase the availability of a network. SCTP does SCTP only tries to increase the availability of a network. SCTP does
not contain any protocol mechanisms which are directly related to not contain any protocol mechanisms which are directly related to
skipping to change at page 16, line 45 skipping to change at page 18, line 40
one must use 2 * N * M security associations if one endpoint uses N one must use 2 * N * M security associations if one endpoint uses N
addresses and the other M addresses. addresses and the other M addresses.
6 References and related work 6 References and related work
[RFC2960] Stewart, R. R., Xie, Q., Morneault, K., Sharp, C. , , [RFC2960] Stewart, R. R., Xie, Q., Morneault, K., Sharp, C. , ,
Schwarzbauer, H. J., Taylor, T., Rytina, I., Kalla, M., Zhang, Schwarzbauer, H. J., Taylor, T., Rytina, I., Kalla, M., Zhang,
L. and Paxson, V, "Stream Control Transmission Protocol", RFC2960, L. and Paxson, V, "Stream Control Transmission Protocol", RFC2960,
October 2000. October 2000.
[RFCOENE] Coene, L., Tuexen, M., Verwimp, G., Loughney, J., Stewart, [RFccccc] Coene, L., Tuexen, M., Verwimp, G., Loughney, J., Stewart,
R. R., Xie, Q., Holdrege, M., Belinchon, M.C., and Jungmayer, A., R. R., Xie, Q., Holdrege, M., Belinchon, M.C., and Jungmayer, A.,
"Stream Control Transmission Protocol Applicability statement", "Stream Control Transmission Protocol Applicability statement",
<draft-ietf-sigtran-sctp-applicability-03.txt>, December 2000. Work RFCzzzz, April 2002.
Draft Telephony UAL AS March 2002
In Progress.
[RFC2719] Ong, L., Rytina, I., Garcia, M., Schwarzbauer, H., Coene, [RFC2719] Ong, L., Rytina, I., Garcia, M., Schwarzbauer, H., Coene,
L., Lin, H., Juhasz, I., Holdrege, M., Sharp, C., "Framework L., Lin, H., Juhasz, I., Holdrege, M., Sharp, C., "Framework
Architecture for Signalling Transport", RFC2719, October 1999 Architecture for Signalling Transport", RFC2719, October 1999.
[SCTPFLOW] Stewart, R., Ramalho, M., Xie, Q., Conrad, P. and Rose, [RFC3057] Morneault, K., Rengasami, S., Kalla, M., Sidebottom, G.,
M., "SCTP Stream based flow control", September 2000, Work in "ISDN Q.921-User Adaptation Layer", RFC3057, February 2001.
Progress.
[RFCxxxx] Morneault, K., Dantu, R., Sidebottom, G., George, T.,
Draft Telephony Signalling AS April 2002
Bidulock, B., Heitz , J., "Signaling System 7 (SS7) Message Transfer
Part (MTP) 2 - User Adaptation Layer", RFCxxxx, May 2002.
[RFCyyyy] Sidebottom, G., Pastor-Balbas, J., Rytina, I., Mousseau,
G., Ong, L., Schwarzbauer, H.J., Gradischnig, K., Morneault, K.,
Kalla, M., Glaude, N., Bidulock, B., Loughney, J., "SS7 MTP3-User
Adaptation Layer (M3UA)", RFCyyyy, May 2002.
[RFCzzzz] Loughney, J., Sidebottom, G., Mousseau, G., Lorusso, S.,
Coene, L., Verwimp, G., Keller, J., Escobar, F., Sully, W., Furniss,
S., Bidulock, B.,"SS7 SCCP-User Adaptation Layer (SUA)", RFCzzzz,
May 2002.
[RFCwwww] George, T., Dantu, R., Kalla, M., Schwarzbauer, H.J.,
Sidebottom, G., Morneault, K.,"SS7 MTP2-User Peer-to-Peer Adaptation
Layer", RFCwwww, June 2002.
[RFCqqqq] Weilandt, E., Khanchandani, N., Rao, S.,"V5.2-User
Adaptation Layer (V5UA)", RFCqqqq, June 2002
[RFCtttt] Vydyam, A., Mukundan, R., Mangalpally, N., Morneault,
K.,"DPNSS/DASS 2 extensions to the IUA protocol", RFCtttt, August
2002.
[ALLMAN99] Allman, M. and Paxson, V., "On Estimating End-to-End [ALLMAN99] Allman, M. and Paxson, V., "On Estimating End-to-End
Network Path Properties", Proc. SIGCOMM'99, 1999. Network Path Properties", Proc. SIGCOMM'99, 1999.
7 Acknowledgments 7 Acknowledgments
This document was initially developed by a design team consisting of This document was initially developed by a design team consisting of
Lode Coene, John Loughney, Michel Tuexen, Randall R. Stewart, Lode Coene, John Loughney, Michel Tuexen, Randall R. Stewart,
Qiaobing Xie, Matt Holdrege, Maria-Carmen Belinchon, Andreas Qiaobing Xie, Matt Holdrege, Maria-Carmen Belinchon, Andreas
Jungmaier, Gery Verwimp and Lyndon Ong. Jungmaier, Gery Verwimp and Lyndon Ong.
The authors wish to thank Renee Revis, H.J. Schwarzbauer, T. Taylor, The authors wish to thank Renee Revis, H.J. Schwarzbauer, T. Taylor,
G. Sidebottom, K. Morneault, T. George, M. Stillman and many others G. Sidebottom, K. Morneault, T. George, M. Stillman and many others
for their invaluable comments. for their invaluable comments.
8 Author's Address 8 Author's Address
Lode Coene Phone: +32-14-252081 Lode Coene Phone: +32-14-252081
Siemens Atea EMail: lode.coene@siemens.atea.be Siemens Atea EMail: lode.coene@siemens.atea.be
Draft Telephony Signalling AS April 2002
Atealaan 34 Atealaan 34
B-2200 Herentals B-2200 Herentals
Belgium Belgium
Javier Pastor-Balbas Phone: Javier Pastor-Balbas Phone:
Ericsson Email: javier.pastor-balbas@ece.ericsson.se Ericsson Espana S.A. Email: j.javier.pastor@ericsson.com
C/ Ombu 3
28045 Madrid
Spain Spain
Expires: August 2002 Expires: August 2002
Draft Telephony UAL AS March 2002
Full Copyright Statement Full Copyright Statement
Copyright (C) The Internet Society (2002). All Rights Reserved. Copyright (C) The Internet Society (2002). All Rights Reserved.
This document and translations of it may be copied and furnished This document and translations of it may be copied and furnished
to others, and derivative works that comment on or otherwise to others, and derivative works that comment on or otherwise
explain it or assist in its implementation may be prepared, explain it or assist in its implementation may be prepared,
copied, published and distributed, in whole or in part, without copied, published and distributed, in whole or in part, without
restriction of any kind, provided that the above copyright notice restriction of any kind, provided that the above copyright notice
and this paragraph are included on all such copies and derivative and this paragraph are included on all such copies and derivative
skipping to change at line 824 skipping to change at page 21, line 4
The limited permissions granted above are perpetual and will not The limited permissions granted above are perpetual and will not
be revoked by the Internet Society or its successors or assigns. be revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on This document and the information contained herein is provided on
an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Draft Telephony Signalling AS April 2002
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