draft-ietf-sigtran-v5ua-02.txt   draft-ietf-sigtran-v5ua-03.txt 
Internet Engineering Task Force Eva Weilandt Internet Engineering Task Force E. Weilandt
INTERNET DRAFT Neeraj Khanchandani INTERNET DRAFT N. Khanchandani
Sanjay Rao S. Rao
Nortel Networks Nortel Networks
Expires in six months February 2002 Expires in six months June 2002
V5.2-User Adaptation Layer (V5UA) V5.2-User Adaptation Layer (V5UA)
<draft-ietf-sigtran-v5ua-02.txt> <draft-ietf-sigtran-v5ua-03.txt>
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with all This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of RFC2026. provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Task Internet-Drafts are working documents of the Internet Engineering Task
Force (IETF), its areas, and its working groups. Note that other Force (IETF), its areas, and its working groups. Note that other
groups may also distribute working documents as Internet- Drafts. groups may also distribute working documents as Internet- Drafts.
skipping to change at page 2, line 15 skipping to change at page 2, line 15
Table of Contents Table of Contents
1. Introduction ................................................. 3 1. Introduction ................................................. 3
1.1. Scope .................................................... 3 1.1. Scope .................................................... 3
1.2. Terminology .............................................. 3 1.2. Terminology .............................................. 3
1.3. V5.2 Overview ............................................ 5 1.3. V5.2 Overview ............................................ 5
1.4. TEI Management for BRI over V5UA ......................... 7 1.4. TEI Management for BRI over V5UA ......................... 7
1.5. Client/Server Model ...................................... 7 1.5. Client/Server Model ...................................... 7
1.6. Addition to boundary primitives .......................... 7 1.6. Addition to boundary primitives .......................... 7
1.6.1. V5 specific boundary primitives ...................... 7 1.6.1. V5 specific boundary primitives ...................... 7
2. SCTP Stream Management ....................................... 9 2. Conventions .................................................. 9
3. Proposed V5.2 Backhaul Architecture .......................... 9 3. SCTP Stream Management ....................................... 9
3.1. V5UA Message Header ...................................... 10 4. Proposed V5.2 Backhaul Architecture .......................... 9
3.2. V5 Naming Conventions for Interface Identifier ........... 11 4.1. V5UA Message Header ...................................... 10
3.3. V5 Additions to IUA Boundary Primitives .................. 12 4.2. V5 Naming Conventions for Interface Identifier ........... 11
3.4. Link Status Messages ..................................... 13 4.3. V5 Additions to IUA Boundary Primitives .................. 12
3.5. Sa-Bit Messages .......................................... 14 4.4. Link Status Messages ..................................... 13
3.6. Error Indication Message ................................. 15 4.5. Sa-Bit Messages .......................................... 15
4. Procedures ................................................... 16 4.6. Error Indication Message ................................. 16
4.1. V5 Layer 1 failure ....................................... 16 5. Procedures ................................................... 17
4.2. Loss of V5UA peer ........................................ 17 5.1. V5 Layer 1 failure ....................................... 17
4.3. C-channel overload on SG ................................. 17 5.2. Loss of V5UA peer ........................................ 17
5. Examples ..................................................... 17 5.3. C-channel overload on SG ................................. 18
5.1. Link Identification Procedure (successful) ............... 18 6. Examples ..................................................... 18
6. IANA Considerations .......................................... 19 6.1. Link Identification Procedure (successful) ............... 18
7. Security Considerations ...................................... 19
8. IANA Considerations .......................................... 19
8.1. SCTP Payload Protocol Identifier ......................... 19
8.2. V5UA Port Number ......................................... 20
9. Acknowledgements ............................................. 20
10. References .................................................. 20
10.1. Normative References .................................... 20
10.2. Informative References .................................. 20
11. Author's Addresses .......................................... 21
1. Introduction 1. Introduction 1. Introduction
This document describes a method of implementing V5.2 backhaul messag- This document describes a method of implementing V5.2 backhaul messag-
ing over IP using a modified version of the ISDN User Adaption Layer ing over IP using a modified version of the ISDN User Adaption Layer
Protocol (IUAP) [1]. The V5UA builds on top of IUA defining the neces- Protocol (IUAP) [1]. The V5UA builds on top of IUA defining the neces-
sary extensions to IUA for a V5.2 implementation. sary extensions to IUA for a V5.2 implementation.
Since V5UA is meant to be an extension to IUAP, everything defined in
[1] is also valid for V5UA unless specified otherwise in this docu-
ment.
1.1. Scope 1.1. Scope
There is a need for Switched Circuit Network (SCN) signaling protocol There is a need for Switched Circuit Network (SCN) signaling protocol
delivery from a V5.2 Signaling Gateway (SG) to a Media Gateway con- delivery from a V5.2 Signaling Gateway (SG) to a Media Gateway Con-
troller (MGC) analog to the implementation of the ISDN Q.921 User troller (MGC) analog to the implementation of the ISDN Q.921 User
Adaption Layer (IUA) as described in [1]. Adaption Layer (IUA) as described in [1].
This draft supports analog telephone access, ISDN basic rate access This draft supports analog telephone access, ISDN basic rate access
and ISDN Primary rate access over a V5.2 interface. and ISDN Primary rate access over a V5.2 interface.
Since the V5.2 Layer 2 and specifically Layer 3 differs from the Q.921 Since the V5.2 Layer 2 and specifically Layer 3 differs from the Q.921
and Q.931 Adaption layer, the IUA standard needs to be extended to and Q.931 Adaption layer, the IUA standard needs to be extended to
fulfil the needs for supporting V5.2. fulfil the needs for supporting V5.2.
skipping to change at page 3, line 42 skipping to change at page 3, line 46
Communication channel (C-channel) - A 64 kbit/s time slot on a V5.2 Communication channel (C-channel) - A 64 kbit/s time slot on a V5.2
interface provisioned to carry communication paths. interface provisioned to carry communication paths.
Communication path (C-path) - Any one of the following information Communication path (C-path) - Any one of the following information
types: types:
- The layer 2 data link carrying the Control protocol - The layer 2 data link carrying the Control protocol
- The layer 2 data link carrying the Link Control protocol - The layer 2 data link carrying the Link Control protocol
- The layer 2 data link carrying the PSTN signalling - The layer 2 data link carrying the PSTN signaling
- Each of the layer 2 data links carrying the protection protocol - Each of the layer 2 data links carrying the protection protocol
- The layer 2 data link carrying the BCC protocol - The layer 2 data link carrying the BCC protocol
- All the ISDN Ds-type data from one or more user ports - All the ISDN Ds-type data from one or more user ports
- All the ISDN p-type data from one or more user ports - All the ISDN p-type data from one or more user ports
- All the ISDN t-type data from one or more user ports - All the ISDN t-type data from one or more user ports
Note: This definition includes the possibility that there is more Note: This definition includes the possibility that there is more
than one C-path of the same information type, each allocated to a than one C-path of the same information type, each allocated to a
different logical C-channel. different logical C-channel.
Envelope Function Address (EFA) - 13 bit number, ranging from 0 to Envelope Function Address (EFA) - 13 bit number, ranging from 0 to
8191 (decimal). An EFA uniquely identifies one of the five V5.2 8191 (decimal). An EFA uniquely identifies one of the five V5.2
protocols, or an ISDN agent attached to an AN. The following list protocols, or an ISDN agent attached to an AN. The following list
contains the possible values for the EFA: contains the possible values for the EFA:
skipping to change at page 4, line 16 skipping to change at page 4, line 19
Envelope Function Address (EFA) - 13 bit number, ranging from 0 to Envelope Function Address (EFA) - 13 bit number, ranging from 0 to
8191 (decimal). An EFA uniquely identifies one of the five V5.2 8191 (decimal). An EFA uniquely identifies one of the five V5.2
protocols, or an ISDN agent attached to an AN. The following list protocols, or an ISDN agent attached to an AN. The following list
contains the possible values for the EFA: contains the possible values for the EFA:
Definition Value Definition Value
---------- ------ ---------- ------
ISDN_PROTOCOL 0 - 8175 ISDN_PROTOCOL 0 - 8175
PSTN_PROTOCOL 8176 PSTN_PROTOCOL 8176
CC_PROTOCOL 8177 CONTROL_PROTOCOL 8177
BCC_PROTOCOL 8178 BCC_PROTOCOL 8178
PROT_PROTOCOL 8179 PROT_PROTOCOL 8179
LINK_CONTROL_PROTOCOL 8180 LINK_CONTROL_PROTOCOL 8180
RESERVED 8181 - 8191 RESERVED 8181 - 8191
Layer 1 Functional State Machine (L1 FSM) - Functional State Machine
in V5 System Management that tracks and controls the states of
the physical E1 links on the interface.
Logical Communication channel (Logical C-channel) - A group of one or Logical Communication channel (Logical C-channel) - A group of one or
more C-paths, all of different types, but excluding the C-path more C-paths, all of different types, but excluding the C-path
for the protection protocol. for the protection protocol.
Multi-link - A collection of more than one 2048 kbit/s link which Multi-link - A collection of more than one 2048 kbit/s link which
together make up a V5.2 interface. together make up a V5.2 interface.
Multi-Slot - A group of more than one 64kbit/s channels providing 8Khz Multi-Slot - A group of more than one 64kbit/s channels providing 8Khz
and time slot sequence integrity, generally used together within and time slot sequence integrity, generally used together within
an ISDN Primary Rate Access (ISDN-PRA) user port, in order to an ISDN Primary Rate Access (ISDN-PRA) user port, in order to
supply a higher bit-rate service. supply a higher bit-rate service.
Physical Communication Channel (Physical C-channel) - A 64kbit/s time Physical Communication Channel (Physical C-channel) - A 64kbit/s time
slot on a V5.2 interface which has been assigned for carrying slot on a V5.2 interface which has been assigned for carrying
logical C-channels. A physical C-channel may not be used for car- logical C-channels. A physical C-channel may not be used for car-
rying bearer channels. rying bearer channels.
Primary Link - A 2048 kbit/s link in a multi-link V5.2 interface whose Primary Link - A 2048 kbit/s (E1) link in a multi-link V5.2 interface
physical C-channel in time slot 16 carries a C-path for the pro- whose physical C-channel in time slot 16 carries a C-path for the
tection protocol and, on V5.2 initialization, also the C-path for protection protocol and, on V5.2 initialization, also the C-path
the control protocol, link control protocol, and the BCC proto- for the control protocol, link control protocol, and the BCC
col. Other C-paths may also be carried in the time slot 16. protocol. Other C-paths may also be carried in the time slot 16.
Secondary Link - A 2048 kbit/s link in a multi-link V5.2 interface Secondary Link - A 2048 kbit/s (E1) link in a multi-link V5.2 inter-
whose time slot 16 carries a C-path for the protection protocol, face whose time slot 16 carries a C-path for the protection pro-
and, on V5.2 initialization, acts as the standby C-channel for tocol, and, on V5.2 initialization, acts as the standby C-channel
the control protocol, link control protocol, and BCC protocol and for the control protocol, link control protocol, and BCC protocol
any other C-paths initially carried in time slot 16 of the and any other C-paths initially carried in time slot 16 of the
primary link. primary link.
Layer 1 Functional State Machine (L1 FSM) - Functional State Machine V5 Link - A 2048 kbits/s E1 (PCM30) link used on a V5 interface. A V5
in V5 System Management that tracks and controls the states of interface may use up to 16 V5 links.
the physical E1 links on the interface.
1.3. V5.2 Overview 1.3. V5.2 Overview
V5.2 is an industry standard ETSI interface (reference ETS 300 347-1) V5.2 is an industry standard ETSI interface (reference ETS 300 347-1
defined between a Local Exchange (LE) and an Access Network (AN) pro- [3]) defined between a Local Exchange (LE) and an Access Network (AN)
viding access to the following types: providing access to the following types:
- Analog telephone access - Analog telephone access
- ISDN Basic rate access - ISDN Basic rate access
- ISDN Primary Rate access - ISDN Primary Rate access
- Other analog or digital accesses for semi-permanent connections - Other analog or digital accesses for semi-permanent connections
without associated outband signaling information without associated outband signaling information
The original V5 specification (V5.1) uses 2048 kbps links in a The original V5 specification (V5.1 [2]) uses 2048 kbps links in
non-concentrating fashion. V5.2 may use up to 16 such interface a non-concentrating fashion. V5.2 may use up to 16 such interface
links and supports concentration. links and supports concentration.
---------- ---------- o--o ---------- ---------- o--o
| | E1 | |------- / | | E1 | |------- /\
| |--------------| | -- | |--------------| | --
| LE | E1 | AN | | LE | E1 | AN |
| |--------------| | o--o | |--------------| | o--o
| | | |------- / | | | |------- /\
---------- ---------- -- ---------- ---------- --
The LE and AN are connected with up to 16 E1 (PCM30) links. Channels The LE and AN are connected with up to 16 E1 (PCM30) links. Channels
16, 15 and 31 on any E1 link can be reserved for data communication 16, 15 and 31 on any E1 link can be reserved for data communication
between LE and AN. The channels reserved for data are called "Communi- between LE and AN. The channels reserved for data are called "Communi-
cation Channels" or "C-Channels." cation Channels" or "C-channels."
The C-Channels are the physical media to exchange data between the The C-channels are the physical media to exchange data between the
V5.2 protocol peer entities, as well as to transfer the ISDN BRI D-Ch V5.2 protocol peer entities, as well as to transfer the ISDN BRI D-
messages between the terminals and the LE. A logical communication
path between two peer entities for one protocol is called a "C-path". channel messages between the terminals and the LE. A logical communi-
cation path between two peer entities for one protocol is called a
"C-path".
The signaling information in V5.2 are defined as: The signaling information in V5.2 are defined as:
- Analog signals are carried by means of the V5 PSTN protocol - Analog signals are carried by means of the V5 PSTN protocol
(L3) (L3)
- ISDN/analog ports are controlled by the V5 Control protocol - ISDN/analog ports are controlled by the V5 Control protocol
(L3) (L3)
- ISDN protocol messages are mapped to LAPD frames, which are - ISDN protocol messages are mapped to LAPD frames, which are
carried by means of LAPV5-EF sublayer (L2) carried by means of LAPV5-EF sublayer (L2)
- V5 protocol messages are mapped to LAPV5-DL frames, which are - V5 protocol messages are mapped to LAPV5-DL frames, which are
carried by means of LAPV5-EF sublayer (L2) carried by means of LAPV5-EF sublayer (L2)
In order to support more traffic and dynamic allocation of bearer In order to support more traffic and dynamic allocation of bearer
skipping to change at page 6, line 18 skipping to change at page 6, line 28
carried by means of LAPV5-EF sublayer (L2) carried by means of LAPV5-EF sublayer (L2)
- V5 protocol messages are mapped to LAPV5-DL frames, which are - V5 protocol messages are mapped to LAPV5-DL frames, which are
carried by means of LAPV5-EF sublayer (L2) carried by means of LAPV5-EF sublayer (L2)
In order to support more traffic and dynamic allocation of bearer In order to support more traffic and dynamic allocation of bearer
channels, the V5.2 protocol has several additions: channels, the V5.2 protocol has several additions:
- A bearer channel connection protocol establishes and de- - A bearer channel connection protocol establishes and de-
establishes bearer connections required on demand, identified establishes bearer connections required on demand, identified
by the signalling information, under the control of the Local by the signaling information, under the control of the Local
Exchange. Exchange.
- A link control protocol is defined for the multi-link manage- - A link control protocol is defined for the multi-link manage-
ment to control link identification, link blocking and link ment to control link identification, link blocking and link
failure conditions. failure conditions.
- A protection protocol, operated on two separate data links for - A protection protocol, operated on two separate V5 data links
security reasons, is defined to manage the protection switching for security reasons, is defined to manage the protection
of communication channels in case of link failures. switching of communication channels in case of link failures.
The following protocols are defined for the various protocol layers: The following protocols are defined for the various protocol layers:
Layer 2: Layer 2:
- LAPV5-EF - LAPV5-EF
- LAPV5-DL - LAPV5-DL
Layer 3: Layer 3:
- V5-Link Control - V5-Link Control
- V5-BCC - V5-BCC
skipping to change at page 8, line 17 skipping to change at page 8, line 17
MDL-RELEASE MDL-RELEASE
The MDL-Release primitive is used to indicate the outcome of the pro- The MDL-Release primitive is used to indicate the outcome of the pro-
cedures for terminating multiple frame operation. cedures for terminating multiple frame operation.
In contrary to ISDN, the V5 standards demand that V5.2 system manage- In contrary to ISDN, the V5 standards demand that V5.2 system manage-
ment interacts directly with V5.2 layer 1. Since V5.2 Layer 1 (includ- ment interacts directly with V5.2 layer 1. Since V5.2 Layer 1 (includ-
ing the L1 FSM) and parts of V5 system management may be physically ing the L1 FSM) and parts of V5 system management may be physically
separated in a V5 backhaul scenario, V5UA needs to support some ser- separated in a V5 backhaul scenario, V5UA needs to support some ser-
vice for the communication between these two entities. Specifically vices for the communication between these two entities. Specifically
these services include an indication of the status of a link, and mes- these services include an indication of the status of a link, and mes-
sages to support link identification procedure. sages to support link identification procedure.
The new primitive are defined as shown below: The new primitive are defined as shown below:
MPH-LINK STATUS START REPORTING MPH-LINK STATUS START REPORTING
The MPH-LINK STATUS START REPORTING primitive is used by V5 system The MPH-LINK STATUS START REPORTING primitive is used by V5 system
management to request to take the link in service for use on a V5 management to request to take the link in service for use on a V5
interface. On reception of this message L1 FSM on the SG shall also interface. On reception of this message L1 FSM on the SG shall also
skipping to change at page 8, line 40 skipping to change at page 8, line 40
MPH-LINK STATUS STOP REPORTING MPH-LINK STATUS STOP REPORTING
The MPH-LINK STATUS STOP REPORTING primitive is used by V5 system The MPH-LINK STATUS STOP REPORTING primitive is used by V5 system
management to request to take the link out of service for use on a V5 management to request to take the link out of service for use on a V5
interface. On reception of this message L1 FSM on the SG shall also interface. On reception of this message L1 FSM on the SG shall also
stop reporting the status of the V5 link to the GWC. stop reporting the status of the V5 link to the GWC.
MPH-LINK STATUS INDICATION MPH-LINK STATUS INDICATION
The MPH-LINK STATUS INDICATION primitive is used by L1 FSM on the Sig- The MPH-LINK STATUS INDICATION primitive is used by L1 FSM on the Sig-
nalling Gateway to report the status (operational/non-operational) of naling Gateway to report the status (operational/non-operational) of a
a V5 link to V5 system management. V5 link to V5 system management.
MPH-SA-BIT SET MPH-SA-BIT SET
The MPH-SA-BIT SET primitive is used by system management to request The MPH-SA-BIT SET primitive is used by system management to request
that the L1 FSM in the SG sets or resets the value of a specified Sa that the L1 FSM in the SG sets or resets the value of a specified Sa
bit on the requested link, or to report the successful setting or bit on the requested link, or to report the successful setting or
resetting of this bit back to system management. For V5 this message resetting of this bit back to system management. For V5 this message
will be used for the Link Identification procedure to set/reset the will be used for the Link Identification procedure to set/reset the
value of the Sa7 bit, or to confirm the successful setting of the Sa value of the Sa7 bit, or to confirm the successful setting of the Sa
bit. The MPH-SA BIT SET REQUEST would be equivalent to the MPH-ID and bit. The MPH-SA BIT SET REQUEST is equivalent to the MPH-ID and MPH-
MPH-NOR primitves in V5.2. NOR primitves in V5.2.
MPH-SA-BIT STATUS MPH-SA-BIT STATUS
The MPH-SA-BIT STATUS primitives are used between system management in The MPH-SA-BIT STATUS primitives are used between system management in
the MGC and L1 FSM in the SG to request reporting of the status of a the MGC and L1 FSM in the SG to request reporting of the status of a
specified Sa bit on the requested link, or to report (indicate) the specified Sa bit on the requested link, or to report (indicate) the
status of this bit back to system management. For V5 these messages status of this bit back to system management. For V5 these messages
will be used for the Link identification procedure to request or will be used for the Link identification procedure to request or
report the status of the Sa7 bit. This would be equivalent to the report the status of the Sa7 bit. This is equivalent to the MPH-IDR,
MPH-IDR, MPH-IDI or MPH-Elg primitive in V5.2. MPH-IDI or MPH-Elg primitive in V5.2.
Due to the separation of V5 System Management and V5 Layer1/Layer2, it
may be necessary to report error conditions of the SG's V5 stack to V5
System Management. For this a new primitive is defined:
MDL-ERROR INDICATION MDL-ERROR INDICATION
The MDL-ERROR INDICATION primitive is used to indicate an error condi- The MDL-ERROR INDICATION primitive is used to indicate an error condi-
tion to V5 System Management. The only valid reason for this primi- tion to V5 System Management. The only valid reason for this primi-
tive is 'Overload', indicating an overload condition of the c-channel tive is 'Overload', indicating an overload condition of the C-channel
on the SG. This reason is not defined in the V5/Q.921 standards. on the SG. This reason is not defined in the V5/Q.921 standards.
2. SCTP Stream Management 2. Conventions
The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
SHOULD NOT, RECOMMENDED, NOT RECOMMENDED, MAY, and OPTIONAL, when they
appear in this document, are to be interpreted as describd in [8].
3. SCTP Stream Management
It is recommended that one SCTP stream be used for BCC, Link Control, It is recommended that one SCTP stream be used for BCC, Link Control,
Common Control and PSTN protocol on a specific c-channel. It is Control and PSTN protocol on a specific C-channel. It is recommended
recommended to use a separate SCTP stream for Protection protocol on a to use a separate SCTP stream for Protection protocol on a specific
specific c-channel. It is also recommended to use one SCTP stream for C-channel. It is also recommended to use one SCTP stream for all ISDN
all ISDN user ports on a specific c-channel. One single stream should user ports on a specific C-channel. One single stream should not be
not be used to carry data of more than one c-channel. used to carry data of more than one C-channel.
In addition, it is recommended that one separate SCTP stream be used In addition, it is recommended that one separate SCTP stream be used
for all MPH (link related) messages. for all MPH (link related) messages.
3. Proposed V5.2 Backhaul Architecture 4. Proposed V5.2 Backhaul Architecture
****** 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 |
+-----+ +-----+----+ +-----+ +-----+ +-----+----+ +-----+
Figure 1 V5.2 Backhaul Architecture Figure 1 V5.2 Backhaul Architecture
AN - Access Network
NIF - Nodal Interworking Function
SCTP - Stream Control Transmission Protocol SCTP - Stream Control Transmission Protocol
3.1. V5UA Message Header 4.1. V5UA Message Header
The original IUA message header needs to be modified for V5. The ori- The original IUA message header needs to be modified for V5. The ori-
ginal header for the integer formatted Interface Identifier is shown ginal header for the integer formatted Interface Identifier is shown
below: 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x1) | Length | | Tag (0x1) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier (integer) | | Interface Identifier (integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x5) | Length=8 | | Tag (0x5) | Length=8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DLCI | Spare | | DLCI | Spare |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2 Original IUA Message Header Figure 2 Original IUA Message Header
For the V5 extension of the IUA Message Header, the Envelope Function For the V5 extension of the IUA Message Header, the Envelope Function
Address (EFA) field is included in the last 13 bits of the Spare Address (EFA) field is included in the Spare field. Below the V5UA
field. Below the V5UA format for the integer formatted Interface Iden- format for the integer formatted Interface Identifier is shown:
tifier is shown:
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 | | Tag (0x1) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier (integer) | | Interface Identifier (integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x5) | Length=8 | | Tag (0x5) | Length=8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 11, line 9 skipping to change at page 11, line 28
The EFA identifies a C-path, which is a 13-bit number, ranging from 0 The EFA identifies a C-path, which is a 13-bit number, ranging from 0
to 8191 (decimal). An EFA uniquely identifies one of the five V5.2 to 8191 (decimal). An EFA uniquely identifies one of the five V5.2
protocols, or an ISDN agent attached to an AN. The following list con- protocols, or an ISDN agent attached to an AN. The following list con-
tains the possible values for the EFA: tains the possible values for the EFA:
Definition Value Definition Value
---------- ------ ---------- ------
ISDN_PROTOCOL 0 - 8175 ISDN_PROTOCOL 0 - 8175
PSTN_PROTOCOL 8176 PSTN_PROTOCOL 8176
CC_PROTOCOL 8177 CONTROL_PROTOCOL 8177
BCC_PROTOCOL 8178 BCC_PROTOCOL 8178
PROT_PROTOCOL 8179 PROT_PROTOCOL 8179
LINK_CONTROL_PROTOCOL 8180 LINK_CONTROL_PROTOCOL 8180
RESERVED 8181 - 8191 RESERVED 8181 - 8191
For MPH messages for which DLCI and EFA are not used, SAPI, TEI and For MPH messages for which DLCI and EFA are not used, SAPI, TEI and
EFA shall be set to ZERO and shall be ignored by the receiver. For all EFA shall be set to ZERO and shall be ignored by the receiver. For all
other messages the DLCI shall be set as defined in the V5.2 standard other messages the DLCI shall be set as defined in the V5.2 standard
[2]. [2].
The Interface Identifier SHALL follow the naming conventions for the The Interface Identifier SHALL follow the naming conventions for the
Interface Identifier as defined below. Interface Identifier as defined below.
3.2. V5 Naming Conventions for Interface Identifier 4.2. V5 Naming Conventions for Interface Identifier
The V5 standard demands that V5 System Management keeps track of the The V5 standard demands that V5 System Management keeps track of the
states of all links on a V5 interface. To perform tasks like protec- states of all links on a V5 interface. To perform tasks like protec-
tion switching and bearer channel allocation on the V5 links, it is tion switching and bearer channel allocation on the V5 links, it is
neccessary that system management has the full picture of the signal- neccessary that system management has the full picture of the signal-
ling and bearer channels located on each link. ing and bearer channels located on each link.
The IUA protocol identifies C-channels by endpoints without a defined
The IUA protocol identifies C-Channels by endpoints without a defined
association with a specific link. Since no naming convention exists, association with a specific link. Since no naming convention exists,
there is no guarantee that a C-Channel is actually located at the link there is no guarantee that a C-channel is actually located at the link
it claims to be. Furthermore the V5 standard requires that the MGC it claims to be. Furthermore the V5 standard requires that the MGC
receives reports of the status of all links, and it defines a link receives reports of the status of all links, and it defines a link
identification procedure to ensure that AN and LE are referencing the identification procedure to ensure that AN and LE are referencing the
same link when they address a link with a Link Control Protocol mes- same link when they address a link with a Link Control Protocol mes-
sage. sage.
It would clearly be against the concept of V5.2 if there was no clear It would clearly be against the concept of V5.2 if there was no clear
association between E1 links and channels. To solve this problem a association between E1 links and channels. To solve this problem a
naming convention MUST be used to ensure this association: naming convention MUST be used to ensure this association:
skipping to change at page 12, line 12 skipping to change at page 12, line 33
| Link Identifier | Chnl ID | | Link Identifier | Chnl ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Link Identifier - Identifier for an E1 link on the SG (27 bits). Must Link Identifier - Identifier for an E1 link on the SG (27 bits). Must
be unique on the SG. This Link Identifier MUST match the Link be unique on the SG. This Link Identifier MUST match the Link
Identifier used in the Link Management Messages defined later in Identifier used in the Link Management Messages defined later in
this document. this document.
Chnl ID - Channel Identifier (5 bits). This is equal to the time-slot Chnl ID - Channel Identifier (5 bits). This is equal to the time-slot
number of the addressed time slot. Possible values are 15, 16 and number of the addressed time slot. Possible values are 15, 16 and
31 representing the possible time slots for C-Channels on a V5 31 representing the possible time slots for C-channels on a V5
interface. For Link Management Messages the Chnl ID must be set interface. For Link Management Messages the Chnl ID must be set
to 0. All other values are reserved for future use. to 0. All other values are reserved for future use.
The text formatted interface identifier shall be coded as the hex The text formatted interface identifier shall be coded as the hex
representation of the integer formatted interface identifier, written representation of the integer formatted interface identifier, written
as a variable length string. as a variable length string.
3.3. V5 Additions to IUA Boundary Primitives 4.3. V5 Additions to IUA Boundary Primitives
Some primitives for the V5 interface boundaries are similar to the Some primitives for the V5 interface boundaries are similar to the
Q.921/Q.931 boundary primitive messages defined in IUA, but they need Q.921/Q.931 boundary primitive messages defined in IUA, but they need
to be handled in a different way. Therefore it is neccessary to dis- to be handled in a different way. Therefore it is neccessary to dis-
tinguish between these two message types by means of the Message Class tinguish between these two message types by means of the Message Class
parameter. parameter.
For all V5 interface boundary primitives, a new Message Class is For all V5 interface boundary primitives, a new Message Class is
introduced: introduced:
9 V5 Boundary Primitives Transport 9 V5 Boundary Primitives Transport
Messages (V5PTM) Messages (V5PTM)
Similar to IUA, other valid message classes for V5UA are: Similar to IUA, other valid message classes for V5UA are:
0 Management (MGMT) Message 0 Management (MGMT) Message
3 ASP State Maintenance (ASPSM) Messages 3 ASP State Maintenance (ASPSM) Messages
4 ASP Traffic Maintenance (ASPTM) Messages 4 ASP Traffic Maintenance (ASPTM) Messages
Q.921/Q.931 boundary primitive messages reused by V5.2 as QPTMV5 Q.921/Q.931 boundary primitive messages reused by V5.2 as V5PTM mes-
messages are: sages are:
1 Data Request Message (MGC -> SG) 1 Data Request Message (MGC -> SG)
2 Data Indication Message (SG -> MGC) 2 Data Indication Message (SG -> MGC)
3 Unit Data Request Message (MGC -> SG) 3 Unit Data Request Message (MGC -> SG)
4 Unit Data Indication Message (SG -> MGC) 4 Unit Data Indication Message (SG -> MGC)
5 Establish Request (MGC -> SG) 5 Establish Request (MGC -> SG)
6 Establish Confirm (SG -> MGC) 6 Establish Confirm (SG -> MGC)
7 Establish Indication (SG -> MGC) 7 Establish Indication (SG -> MGC)
8 Release Request (MGC -> SG) 8 Release Request (MGC -> SG)
9 Release Confirm (SG -> MGC) 9 Release Confirm (SG -> MGC)
10 Release Indication (SG -> MGC) 10 Release Indication (SG -> MGC)
All these messages are defined similar to the QPTM messages. In addi- All these messages are defined similar to the QPTM messages. In addi-
tion, Layer 1 boundary primitive messages are defined: tion, new boundary primitive messages are defined:
11 Link Status Start Reporting (MGC -> SG) 11 Link Status Start Reporting (MGC -> SG)
12 Link Status Stop Reporting (MGC -> SG) 12 Link Status Stop Reporting (MGC -> SG)
13 Link Status Indication (SG -> MGC) 13 Link Status Indication (SG -> MGC)
14 Sa-Bit Set Request (MGC -> SG) 14 Sa-Bit Set Request (MGC -> SG)
15 Sa-Bit Set Confirm (SG -> MGC) 15 Sa-Bit Set Confirm (SG -> MGC)
16 Sa-Bit Status Request (MGC -> SG) 16 Sa-Bit Status Request (MGC -> SG)
17 Sa-Bit Status Indication (SG -> MGC) 17 Sa-Bit Status Indication (SG -> MGC)
18 Error Indication (SG -> MGC) 18 Error Indication (SG -> MGC)
3.4. Link Status Messages (Start Reporting, Stop Reporting, Indica- 4.4. Link Status Messages (Start Reporting, Stop Reporting, Indica-
tion) tion)
The Link Status Messages are used between V5 System Management on the The Link Status Messages are used between V5 System Management on the
MGC and the L1 FSM on the SG to track the status of a particular E1 MGC and the L1 FSM on the SG to track the status of a particular E1
link. This is required regardless of whether or not the E1 link car- link. This is required regardless of whether or not the E1 link car-
ries c-channels. ries C-channels.
All Link Status Messages contain the V5UA Message Header. The Link All Link Status Messages contain the V5UA Message Header. The Link
Identifier portion of the Interface Identifier identifies the physical Identifier portion of the Interface Identifier identifies the physical
link on the SG addressed by the message. For all link status messages, link on the SG addressed by the message. For all link status messages,
the Chnl ID shall be set to '0' and shall be ignored by the receiver. the Chnl ID shall be set to '0' and shall be ignored by the receiver.
The integer value used for the Link Identifier is of local signifi- The integer value used for the Link Identifier is of local signifi-
cance only, coordinated between the SG and MGC. It has to be unique cance only, coordinated between the SG and MGC. It has to be unique
for the link on the SG. for every V5 link on the SG.
The Link Status Start Report Message is used by V5 System Management The Link Status Start Report Message is used by V5 System Management
to request from L1 FSM to start reporting the status of a particular to request from L1 FSM to start reporting the status of a particular
link, since V5 System Management on the MGC must know the status of link, since V5 System Management on the MGC must know the status of
the links on all active V5 interfaces. This message is also an indica- the links on all active V5 interfaces. This message is also an indica-
tion for the SG that this link is located on a now active interface. tion for the SG that this link is located on a now active interface.
V5 system management shall send this Message on interface activation V5 system management shall send this Message on interface activation
for all links on the interface. The SG will respond immediately to for all links on the interface. The SG will respond immediately to
this request with a Link Status Indication message, and it will then this request with a Link Status Indication message, and it will then
skipping to change at page 13, line 54 skipping to change at page 14, line 25
link status. Since the SG has no other way to determine whether a link link status. Since the SG has no other way to determine whether a link
is on an active interface or not, this message shall always be sent on is on an active interface or not, this message shall always be sent on
interface startup. interface startup.
To stop this reporting of the status of a link, e.g. at interface To stop this reporting of the status of a link, e.g. at interface
deactivation, System Management sends a Link Status Stop Reporting deactivation, System Management sends a Link Status Stop Reporting
Message to the L1 FSM. The SG will then immediately stop reporting the Message to the L1 FSM. The SG will then immediately stop reporting the
status of the particular link and will assume the link to be out of status of the particular link and will assume the link to be out of
service. It must not respond in any way to this message. service. It must not respond in any way to this message.
Since there is not other way for the SG to know that an interface is Since there is no other way for the SG to know that an interface is
deactivated, this message shall be sent on interface deactivation for deactivated, this message shall be sent on interface deactivation for
all links on the interface. On reception of this message, the SG may all links on the interface. On reception of this message, the SG may
take L2 down on this link. take L2 down on this link.
The Link Status Start/Stop Report Messages contain the common message The Link Status Start/Stop Report Messages contain the common message
header followed by the V5UA message header. They do not contain any header followed by the V5UA message header. They do not contain any
addition parameters. addition parameters.
The Link Status Indication Message is used by L1 FSM in the SG in The Link Status Indication Message is used by L1 FSM in the SG in
response to a Link Status Request Message to indicate the status of response to a Link Status Request Message to indicate the status of
skipping to change at page 14, line 36 skipping to change at page 15, line 4
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 (0x11) | Length | | Tag (0x11) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Status | | Link Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The valid values for Link Status are shown in the following table: The valid values for Link Status are shown in the following table:
Define Value Description Define Value Description
OPERATIONAL 0x0 Link is in operation OPERATIONAL 0x0 Link is in operation
NON-OPERATIONAL 0x1 Link is not in operation NON-OPERATIONAL 0x1 Link is not in operation
3.5. Sa-Bit Messages (Set Request, Set Confirm, Status Request, 4.5. Sa-Bit Messages (Set Request, Set Confirm, Status Request,
Status Indication) Status Indication)
The Sa-Bit Messages are used between V5 System Management in the MGC The Sa-Bit Messages are used between V5 System Management in the MGC
and the L1 FSM in the SG to set and read the status of Sa bits on the and the L1 FSM in the SG to set and read the status of Sa bits on the
E1 links. For V5 it is only required to set and read the status of the E1 links. For V5 it is only required to set and read the status of the
Sa7 bit that is used in the V5 defined Link Identification procedure. Sa7 bit that is used in the V5 defined Link Identification procedure.
All Sa-Bit Messages contain the V5UA message header. The Link Identif- All Sa-Bit Messages contain the V5UA message header. The Link Identif-
ier portion of the Interface Identifier identifies the physical link ier portion of the Interface Identifier identifies the physical link
on the SG addressed by the message. For all link status messages, the on the SG addressed by the message. For all link status messages, the
skipping to change at page 15, line 48 skipping to change at page 16, line 16
Sa7 0x7 Addresses the Sa7 bit Sa7 0x7 Addresses the Sa7 bit
There are no other valid values for V5UA. All other values are There are no other valid values for V5UA. All other values are
reserved for future use. reserved for future use.
For the Sa-Bit Status Request and Set Confirm messages, the BIT Value For the Sa-Bit Status Request and Set Confirm messages, the BIT Value
should be set to '0' by the sender and should be ignored by the should be set to '0' by the sender and should be ignored by the
receiver. receiver.
3.6. Error Indication Message 4.6. Error Indication Message
The Error Indication Message is used between the V5 stack on the SG The Error Indication Message is used between the V5 stack on the SG
and the V5 System Management in the MGC to indicate an error condition and the V5 System Management in the MGC to indicate an error condition
of the SG. of the SG.
The only valid reason for the Error Indication Message is Overload. The only valid reason for the Error Indication Message is Overload.
The SG shall issue such an Error Indication with reason Overload for a The SG shall issue such an Error Indication with reason Overload for a
c-channel in case it is not able to process all Layer 3 messages on C-channel in case it is not able to process all Layer 3 messages on
this c-channel in a timely manner (overload condition of the c- this C-channel in a timely manner (overload condition of the C-
channel). channel).
The Error Indication message contain the V5UA message header. The The Error Indication message contain the V5UA message header. The
Interface Identifiers indicates the affected c-channel. SAPI, TEI and Interface Identifiers indicates the affected C-channel. SAPI, TEI and
EFA shall be set to '0' and shall be ignored by the receiver. EFA shall be set to '0' and shall be ignored by the receiver.
The Error Indication message contain the following additional parame- The Error Indication message contain the following additional parame-
ter: ter:
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 (0x13) | Length | | Tag (0x13) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Reason | | Error Reason |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The valid values for Error Reason are shown in the following table: The valid values for Error Reason are shown in the following table:
Define Value Description Define Value Description
OVERLOAD 0x1 C-Channel is in overload state OVERLOAD 0x1 C-channel is in overload state
There are no other valid values for V5UA. All other values are There are no other valid values for V5UA. All other values are
reserved for future use. reserved for future use.
4. Procedures 5. Procedures
4.1. V5 Layer 1 failure 5.1. V5 Layer 1 failure
The normal way to handle a Layer 1 failure is described in the V5 The normal way to handle a Layer 1 failure is described in the V5
standards[2,3] as follows: standards[2,3] as follows:
- L1FSM detects the Layer 1 failure. It reports this to V5 System - The L1 FSM detects the Layer 1 failure. It reports this to V5
management by sending a MPH-DI primitive for the affected link. System management by sending a MPH-DI primitive for the
affected link.
- V5 System management notifies Layer 2 of the Layer 1 outage by - V5 System management notifies Layer 2 of the Layer 1 outage by
sending a MPH-Layer_1 Failure Ind primitive. sending a MPH-Layer_1 Failure Ind primitive.
Since Layer1/2 and V5 System Management are no longer co-located in Since Layer1/2 and V5 System Management are no longer co-located in
the backhaul architecture, it does not make sense to notify Layer 2 the backhaul architecture, it does not make sense to notify Layer 2
about Layer 1 failure via V5 system management. Instead Layer 2 shall about Layer 1 failure via V5 system management. Instead Layer 2 shall
be notified directly by Layer 1 on the SG. Layer 1 shall still report be notified directly by Layer 1 on the SG. Layer 1 shall still report
the outage to V5 system management by sending an MPH-DI primitive, but the outage to V5 system management by sending an MPH-DI primitive, but
V5 system management shall not send a MPH-Layer_1 Failure Ind primi- V5 system management shall not send a MPH-Layer_1 Failure Ind primi-
tive to Layer 2. tive to Layer 2.
4.2. Loss of V5UA peer 5.2. Loss of V5UA peer
If SCTP failure is detected or the heartbeat is lost, the following If SCTP failure is detected or the heartbeat is lost, the following
procedure shall be performed: procedure shall be performed:
When loss of V5UA peer is reported to the V5UA layer, the ASP shall When loss of V5UA peer is reported to the V5UA layer, the ASP shall
behave as if it had received a Link Status Indication (non- behave as if it had received a Link Status Indication (non-
operational) for all links on this SG. operational) for all links on this SG.
The ASP shall attempt to reestablish the connection continuously. When The ASP shall attempt to reestablish the connection continuously. When
the connection is reestablished, the ASP shall send a Link Status the connection is reestablished, the ASP shall send a Link Status
skipping to change at page 17, line 32 skipping to change at page 17, line 49
faces on the SG. faces on the SG.
An example for the message flow in case of reestablishment of the con- An example for the message flow in case of reestablishment of the con-
nection is shown below for one active link on the SG: nection is shown below for one active link on the SG:
ASP SG ASP SG
| | | |
| -------- Link Status Start Reporting ---------> | | -------- Link Status Start Reporting ---------> |
| | | |
| <--------- Link Status Ind (op) --------------- | | <------ Link Status Ind (operational) --------- |
| | | |
In case the association can be reestablished before the V5UA layer In case the association can be reestablished before the V5UA layer
gets notified, communication should proceed as usual and no other gets notified, communication should proceed as usual and no other
action shall be taken by the ASP. action shall be taken by the ASP.
4.3. C-channel overload on SG 5.3. C-channel overload on SG
If the SG detects an overload condition on a c-channel, it shall indi- If the SG detects an overload condition on a C-channel, it shall indi-
cate this by sending an Error Indication message, reason Overload to cate this by sending an Error Indication message, reason Overload to
the MGC. The MGC may then take appropriate actions to clear this over- the MGC. The MGC may then take appropriate actions to clear this over-
load condition. load condition.
The SG shall resent the Error Indication message with reason Overload The SG shall resent the Error Indication message with reason Overload
as long as the overload condition persist. A recommended interval for as long as the overload condition persist. A recommended interval for
resent of this message is 120 seconds. resent of this message is 120 seconds.
5. Examples 6. Examples
5.1. Link Identification Procedure (successful) 6.1. Link Identification Procedure (successful)
An example for the message flow for an LE initiated Link Identifica- A message flow example for an LE initiated Link Identification pro-
tion procedure is shown below. An active association between ASP and cedure is shown below. An active association between ASP and SG is
SG is established prior to the following messages flows, and the V5 established prior to the following messages flows, and the V5 inter-
interface is already activated: face is already activated:
ASP SG ASP SG
| | | |
| ------ Data Request (LnkCtrl: FE-IDReq) ------> | | ------ Data Request (LnkCtrl: FE-IDReq) ------> |
| <-- Data Indication (LnkCtrl Ack: FE-IDReq) --- | | <-- Data Indication (LnkCtrl Ack: FE-IDReq) --- |
| | | |
| <---- Data Indication (LnkCtrl: FE-IDAck) ----- | | <---- Data Indication (LnkCtrl: FE-IDAck) ----- |
| ---- Data Request (LnkCtrl Ack: FE-IDAck) ----> | | ---- Data Request (LnkCtrl Ack: FE-IDAck) ----> |
| | | |
skipping to change at page 19, line 5 skipping to change at page 19, line 24
| ------- Data Request (LnkCtrl: FE-IDAck) -----> | | ------- Data Request (LnkCtrl: FE-IDAck) -----> |
| <-- Data Indication (LnkCtrl Ack: FE-IDAck) --- | | <-- Data Indication (LnkCtrl Ack: FE-IDAck) --- |
| | | |
| <---- Data Indication (LnkCtrl: FE-IDRel) ----- | | <---- Data Indication (LnkCtrl: FE-IDRel) ----- |
| ---- Data Request (LnkCtrl Ack: FE-IDRel) ----> | | ---- Data Request (LnkCtrl Ack: FE-IDRel) ----> |
| | | |
| ------------ Sa-Bit Set Req ( Sa7, ONE ) -----> | | ------------ Sa-Bit Set Req ( Sa7, ONE ) -----> |
| <----------- Sa-Bit Set Conf (Sa 7) ----------- | | <----------- Sa-Bit Set Conf (Sa 7) ----------- |
| | | |
6. IANA Considerations 7. Security Considerations
6.1. SCTP Payload Protocol Identifiers All security considerations applicable for IUA shall also be applica-
ble for V5UA.
A request will be made to IANA to assign an V5UA value for the Payload 8. IANA Considerations
Protocol Identifier in SCTP Payload Data chunk. The following SCTP
Payload Protocol Identifier will be registered: 8.1. SCTP Payload Protocol Identifiers
IANA has assigned a V5UA value for the Payload Protocol Identifier in
the SCTP DATA chunk. The following SCTP Payload Protocol identifier is
registered:
V5UA "6" V5UA "6"
The SCTP Payload Protocol Identifier is included in each SCTP Data the SCTP Payload Protocol identifier value "6" SHOULD be included in
chunk, to indicate which protocol the SCTP is carrying. This Payload each SCTP DATA chunk to indicate that the SCTP is carrying the V5UA
Protocol Identifier is not directly used by SCTP but MAY be used by protocol. The value "0" (unspecified) is also allowed but any other
certain network entities to identify the type of information being values MUST not be used. This Payload Protocol Identifier is not
carried in a Data chunk. directly used by SCTP but MAY be used by certain network 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 The User Adaptation peer MAY use the Payload Protocol Identifier as a
way of determining additional information about the data being way of determining additional information about the data being
presented to it by SCTP. presented to it by SCTP.
7. Acknowledgements 8.2. V5UA Port Number
IANA has registered SCTP (and UDP/TCP) Port Number 5675 for V5UA.
9. Acknowledgements
The authors would like to thank Fahir Ergincan, Milos Pujic, Graeme The authors would like to thank Fahir Ergincan, Milos Pujic, Graeme
Currie, Berthold Jaekle for their valuable comments and suggestions. Currie, Berthold Jaekle, Ken Morneault and Lyndon Ong for their valu-
able comments and suggestions.
8. References 10. References
[1] ISDN Q.921-User Adaptation Layer RFC 3057 10.1. Normative References
[2] EN 300 324-1 (1999): V interfaces at the digital Local Exchange [1] RFC 3057, "ISDN Q.921-User Adaptation Layer", K. Morneault, S.
(LE); V5.1 interface for the support of Access Network (AN); Part Rengasami, M. Kalla, G. Sidebottom, February 2001
1: V5.1 interface specification.
[3] EN 300 347-1 (1999): V interfaces at the digital Local Exchange [2] ETSI EN 300 324-1 (1999): V interfaces at the digital Local
(LE); V5.2 interface for the support of Access Network (AN); Part Exchange (LE); V5.1 interface for the support of Access Network
1: V5.2 interface specification. (AN); Part 1: V5.1 interface specification.
[4] ETS 300 125 (1991) : DSS1 protocol; User-Network interface data [3] ETSI EN 300 347-1 (1999): V interfaces at the digital Local
link layer specification; (Standard is based on : ITU Q.920, Exchange (LE); V5.2 interface for the support of Access Network
(AN); Part 1: V5.2 interface specification.
[4] ETSI ETS 300 125 (1991) : DSS1 protocol; User-Network interface
data link layer specification; (Standard is based on : ITU Q.920,
Q.921). Q.921).
[5] ETS 300 166 (08/1993) : Transmission and Multiplexing; Physical [5] ETSI ETS 300 166 (08/1993) : Transmission and Multiplexing; Phy-
and electrical characteristic of hierarchical digital interfaces sical and electrical characteristic of hierarchical digital
(Standard is based on G.703). interfaces (Standard is based on G.703).
[6] ETS 300 167 (08/1993) : Transmission and Multiplexing; Functional [6] ETSI ETS 300 167 (08/1993) : Transmission and Multiplexing; Func-
characteristic of 2048 kbits/s interfaces (Standard is based on tional characteristic of 2048 kbits/s interfaces (Standard is
G.704, G.706). based on G.704, G.706).
9. Author's Addresses 10.2. Informative References
[7] RFC 2960, "Stream Control Transport Protocol", R. Stewart et al,
October 2000
[8] RFC 2119, "Kay words for use in RFCs to Indicate Requirement Lev-
els", S. Bradner, March 1997
[9] <draft-rfc-editor-rfc2223bis-02.txt>, "Instructions to Request
for Comments (RFC) Authors", J.Reynolds, R. Braden, April 2002
(Work in Progress)
11. Author's Addresses
Dr. Eva Weilandt Tel +49 7545 96 7267 Dr. Eva Weilandt Tel +49 7545 96 7267
Nortel Networks Germany Email eva.weilandt@nortelnetworks.com Nortel Networks Germany Email eva.weilandt@nortelnetworks.com
88039 Friedrichshafen 88039 Friedrichshafen
Germany Germany
Sanjay Rao Tel +1-919-991-2251 Sanjay Rao Tel +1-919-991-2251
Nortel Networks Email rsanjay@nortelnetworks.com Nortel Networks Email rsanjay@nortelnetworks.com
35 Davis Drive 35 Davis Drive
Research Triangle Park, NC 27709 Research Triangle Park, NC 27709
USA USA
Neeraj Khanchandani Tel +1-919-991-2274 Neeraj Khanchandani Tel +1-919-991-2274
Nortel Networks Email neerajk@nortelnetworks.com Nortel Networks Email neerajk@nortelnetworks.com
35 Davis Drive 35 Davis Drive
Research Triangle Park, NC 27709 Research Triangle Park, NC 27709
USA USA
This Draft Expires in 6 months from February,2002 This Draft Expires in 6 months from June 2002
 End of changes. 

This html diff was produced by rfcdiff 1.23, available from http://www.levkowetz.com/ietf/tools/rfcdiff/