draft-ietf-sigtran-signalling-over-sctp-applic-05.txt   draft-ietf-sigtran-signalling-over-sctp-applic-06.txt 
INTERNET-DRAFT L. Coene(Ed) INTERNET-DRAFT L. Coene(Ed)
Internet Engineering Task Force Siemens Internet Engineering Task Force Siemens
Issued: April 2002 J. Pastor Issued: November 2002 J. Pastor
Expires: September 2002 Ericsson Expires: May 2003 Ericsson
Telephony Signalling Transport over SCTP applicability statement Telephony Signalling Transport over SCTP applicability statement
<draft-ietf-sigtran-signalling-over-sctp-applic-05.txt> draft-ietf-sigtran-signalling-over-sctp-applic-06.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 33 skipping to change at page 1, line 33
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1ID-abstracts.txt http://www.ietf.org/ietf/1ID-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html http://www.ietf.org/shadow.html
Abstract Abstract
This document describes the applicability of the new protocols This document describes the applicability of the new protocols
developed under the signaling transport framework[RFC2719]. A developed under the signalling transport framework[RFC2719]. A
description of the main issues regarding the use of the Stream description of the main issues regarding the use of the Stream
Control Transmission Protocol (SCTP)[RFC2960] and each adaptation Control Transmission Protocol (SCTP)[RFC2960] and each adaptation
layer for transport of telephony signalling information over IP layer for transport of telephony signalling information over IP
infrastructure is explained. infrastructure is explained.
Draft Telephony Signalling AS April 2002 Draft Telephony Signalling AS October 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: Scope ..... ....................................... 3 Chapter 1.1: Scope ..... ....................................... 3
Chapter 1.2: Terminology ....................................... 3 Chapter 1.2: Terminology ....................................... 3
Chapter 1.3: Contributors ...................................... 3 Chapter 1.3: Contributors ...................................... 3
Chapter 2: SIGTRAN architecture ................................ 4 Chapter 2: SIGTRAN architecture ................................ 4
Chapter 2.1: Overview ......................................... 4 Chapter 2.1: Overview ......................................... 4
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information over SCTP .......................................... 6 information over SCTP .......................................... 6
Chapter 3.1: Congestion control ................................ 6 Chapter 3.1: Congestion control ................................ 6
Chapter 3.2: Detection of failures ............................. 6 Chapter 3.2: Detection of failures ............................. 6
Chapter 3.2.1: Retransmission TimeOut (RTO) calculation ........ 7 Chapter 3.2.1: Retransmission TimeOut (RTO) calculation ........ 7
Chapter 3.2.2: Heartbeat ....................................... 7 Chapter 3.2.2: Heartbeat ....................................... 7
Chapter 3.2.3: Maximum Number of retransmissions ............... 7 Chapter 3.2.3: Maximum Number of retransmissions ............... 7
Chapter 3.3: Shorten end-to-end message delay ................. 7 Chapter 3.3: Shorten end-to-end message delay ................. 7
Chapter 3.4: Bundling considerations ........................... 8 Chapter 3.4: Bundling considerations ........................... 8
Chapter 3.5: Stream Usage ...................................... 8 Chapter 3.5: Stream Usage ...................................... 8
Chapter 4: User Adaptation Layers............................... 8 Chapter 4: User Adaptation Layers............................... 8
Chapter 4.1: IUA (ISDN Q.921 User Adaptation) .................. 10 Chapter 4.1: Access Signalling.................................. 11
Chapter 4.2: V5UA (V5.2-User Adaptation) Layer ................. 11 Chapter 4.1.1: IUA (ISDN Q.921 User Adaptation) ................ 11
Chapter 4.3: DUA (DPNSS/DASS User adaptation) Layer ............ 12 Chapter 4.1.2: V5UA (V5.2-User Adaptation) Layer ............... 12
Chapter 4.4: M2UA (SS7 MTP2 User Adaptation) Layer ............. 12 Chapter 4.1.3: DUA (DPNSS/DASS User adaptation) Layer .......... 13
Chapter 4.5: M2PA (SS7 MTP2-User Peer-to-Peer Adaptation) Layer. 13 Chapter 4.2: Network Signalling ................................ 13
Chapter 4.6: M3UA (SS7 MTP3 User Adaptation) Layer ............. 15 Chapter 4.2.1: MTP lvl3 over IP ................................ 14
Chapter 4.7: SUA (SS7 SCCP User Adaptation) Layer .............. 16 Chapter 4.2.1.1: M2UA (SS7 MTP2-User Adaptation) Layer ......... 14
Chapter 5: Security considerations ............................. 18 Chapter 4.2.1.2: M2PA (SS7 MTP2-User Peer-to-Peer Adaptation) .. 15
Chapter 6: References and related work ......................... 18 Chapter 4.2.1.3: Main difference between M2PA and M2UA ......... 16
Chapter 7: Acknowledgments ..................................... 19 Chapter 4.2.2: M3UA (SS7 MTP3 User Adaptation) Layer ........... 17
Chapter 8: Author's address .................................... 19 Chapter 4.2.3: SUA (SS7 SCCP User Adaptation) Layer ............ 18
Chapter 5: Security considerations ............................. 20
Chapter 6: References and related work ......................... 20
Chapter 7: Acknowledgments ..................................... 21
Chapter 8: Author's address .................................... 22
1 INTRODUCTION 1 INTRODUCTION
Draft Telephony Signalling AS October 2002
This document intends to inform how to transport telephony This document intends to inform how to transport telephony
signalling protocols, used in classic telephony systems, over IP signalling protocols, used in classic telephony systems, over IP
networks. The whole architecture is called SIGTRAN (Signalling networks. The whole architecture is called SIGTRAN (Signalling
Draft Telephony Signalling AS April 2002
Transport) as described in RFC2719 and is composed of a transport Transport) as described in RFC2719 and is composed of a transport
protocol(SCTP) and several User Adaptation (UAL) layers. The protocol(SCTP) and several User Adaptation layers(UAL). The
transport protocol SCTP has been been developed to fulfill the transport protocol SCTP has been been developed to fulfill the
stringent requirements that telephony signalling networks have. The stringent requirements that telephony signalling networks have. The
set of User Adaptation layers have also been introduced to make it set of User Adaptation layers have also been introduced to make it
possible that different signalling protocols can use the SCTP layer. possible that different signalling protocols can use the SCTP layer.
1.1 Scope 1.1 Scope
The scope of this document is to explain the way that user The scope of this document is to explain the way that user
adaptation layers and SCTP protocols have to be used to transport adaptation layers and SCTP protocols have to be used to transport
Telephony signalling information over IP. Telephony signalling information over IP.
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layer telephony signalling protocols that are to be transported over layer telephony signalling protocols that are to be transported over
SCTP/IP. SCTP/IP.
ISEP: IP signalling endpoint: a IP node that implements SCTP and a ISEP: IP signalling endpoint: a IP node that implements SCTP and a
User adapatation layer. User adapatation layer.
SP: signalling point SP: signalling point
1.3 Contributors 1.3 Contributors
Draft Telephony Signalling AS October 2002
The following people contributed to the document: L. Coene(Editor), The following people contributed to the document: L. Coene(Editor),
M. Tuexen, G. Verwimp, J. Loughney, R.R. Stewart, Qiaobing Xie, M. Tuexen, G. Verwimp, J. Loughney, R.R. Stewart, Qiaobing Xie,
M. Holdrege, M.C. Belinchon, A. Jungmaier, J. Pastor and L. Ong. M. Holdrege, M.C. Belinchon, A. Jungmaier, J. Pastor and L. Ong.
Draft Telephony Signalling AS April 2002
2 SIGTRAN architecture 2 SIGTRAN architecture
The SIGTRAN architecture describes the transport of signalling The SIGTRAN architecture describes the transport of signalling
information over IP infrastructure. information over IP infrastructure.
Telephony Signalling transport over IP normally uses the following Telephony Signalling transport over IP normally uses the following
architecture: architecture:
Telephony Signalling Application Telephony Signalling Application
| |
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(3) The standard Internet Protocol. (3) The standard Internet Protocol.
The telephony signalling protocols to be transported can be: The telephony signalling protocols to be transported can be:
- SS7 MTP3 users: SCCP, ISUP, TUP... - SS7 MTP3 users: SCCP, ISUP, TUP...
- SS7 MTP2 users: MTP3 - SS7 MTP2 users: MTP3
- SS7 SCCP users: RANAP, MAP(+TCAP), INAP(+TCAP)... - SS7 SCCP users: RANAP, MAP(+TCAP), INAP(+TCAP)...
Draft Telephony Signalling AS October 2002
- ISDN Q.921 users: Q.931 - ISDN Q.921 users: Q.931
- V5.2/DSS1 - V5.2/DSS1
- .... - ....
Draft Telephony Signalling AS April 2002
Every classic telephony protocol can have a corresponding UAL Every classic telephony protocol can have a corresponding UAL
developed. developed.
The user adaptation layers(UALs) are a set of protocols that The user adaptation layers(UALs) are a set of protocols that
encapsulate a specific signalling protocol to be transported over encapsulate a specific signalling protocol to be transported over
SCTP. The adapation is done in a way that the upper signalling SCTP. The adapation is done in a way that the upper signalling
protocols that are relayed remain unaware that the lower layers are protocols that are relayed remain unaware that the lower layers are
different to the originail lower telephony signalling layers. In different to the originail lower telephony signalling layers. In
that sense, the upper interface of the user adapatation layers need that sense, the upper interface of the user adapatation layers need
to be the same as the upper layer interface to its original lower to be the same as the upper layer interface to its original lower
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- Graceful termination of association - Graceful termination of association
- Support of multi-homing for added reliability - Support of multi-homing for added reliability
- Protection against blind denial-of-service attacks - Protection against blind denial-of-service attacks
- Protection against blind masquerade attacks - Protection against blind masquerade attacks
SCTP is used as the transport protocol for telephony signalling 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 by SCTP and so each UA can specify its own message transport by SCTP and so each UAL can specify its own message
structure withing the SCTP user data. The SCTP user data can be structure withing the SCTP user data. The SCTP user data can be
delivered by the order of transmission within a stream(in sequence delivered by the order of transmission within a stream(in sequence
delivery) or unordered. delivery) or unordered.
Draft Telephony Signalling AS October 2002
SCTP can be used to provide redundancy 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 redundancy 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
Transport of telephony signalling requires special Transport of telephony signalling requires special
considerations. In order to use SCTP, special care must be taken to considerations. In order to use SCTP, special care must be taken to
meet the performance, timing and failure management requirements. meet the performance, timing and failure management requirements.
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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. with the congestion control procedures in SCTP.
3.2 Detection of failures 3.2 Detection of failures
Telephony systems often must have no single point of failure in Telephony systems often must have no single point of failure in
operation. operation.
The UA must meet certain service availability and performance The UAL must meet certain service availability and performance
requirements according to the classical signalling layers they are requirements according to the classical signalling layers they are
replacing. Those requirements may be specific for each UA.
Draft Telephony Signalling AS October 2002
replacing. Those requirements may be specific for each UAL.
For example, telephony systems are often required to be able to For example, telephony systems are often required to be able to
preserve stable calls during a component failure. Therefore error preserve stable calls during a component failure. Therefore error
situations at the transport layer and below must be detected quickly situations at the transport layer and below must be detected quickly
so that the UAL can take approriate steps to recover and preserve the
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 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
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HB.interval. It should be noted this might 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 fault detections might increase. probability of false fault detections might increase.
Draft Telephony Signalling AS October 2002
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 method described in section 3.2.1 on lowering RTO may delays. The method described in section 3.2.1 on lowering RTO may
Draft Telephony Signalling AS April 2002
be considered. The different paths within a single association will be considered. The different paths within a single association will
have a different RTO, so using the path with the lowest RTO 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 lead to a shorter end-to-end message delay for the application
running on top of the UA's. running on top of the UAL'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
Users Adaptation Layers have been defined to encapsulate different Users Adaptation Layers (UALs) are defined to encapsulate different
signalling protocols in order to transport them over SCTP/IP. signalling protocols in order to transport them over SCTP/IP
There are UALs for both access signalling (DSS1) and trunk signalling 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
- Supports seamless operation of UALs user peers over an IP network - Supports seamless operation of UALs user peers over an IP
connection. network connection.
- Supports 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.
Draft Telephony Signalling AS October 2002
- Supports 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
- Supports asynchronous reporting of status changes to management. - Supports asynchronous reporting of status changes to management.
Draft Telephony Signalling AS April 2002 Signalling User Adaptation Layers have been developed for both:
Access and Trunk Telephony Signalling. They are defined as follows.
Two main scenarios have been developed for Signalling Transport: Access Signalling: This is the signalling that is needed between and
access device and an exchange in the core network in order to
establish, manage or release the voice or data call paths. There
are several protocols that have been developed for this purpose.
- Intercommunication of traditional Signalling transport nodes and IP Trunk Signalling: This is the signalling that is used between the
based nodes. exchanges inside the core network in order to establish, manage or
release the voice or data call paths. The most common protocols
used for this purpose are known as the SS7 system that belongs to
the Common Channel Signalling (CCS) philosophy. The SS7 protocol
stack is depicted below:
+------+-----+-------+- -+-------+------+-----+------+
| | | | | | MAP | CAP | INAP |
+ | + RANAP |...| BSSAP +-------------------+
| ISUP | TUP | | | | TCAP |
+ | +---------------------------------------+
| | | SCCP |
+----------------------------------------------------+
| MTP3 |
+----------------------------------------------------+
| MTP2 |
+----------------------------------------------------+
| MTP1 |
+----------------------------------------------------+
The Telephony Signalling Protocols to be transported with the already
designed UALS are:
- ISDN Q.921 Users: Q.931
- V5.2/DSS1
- DPNSS/DASS2
- SS7 MTP3 Users: SCCP, ISUP, TUP
- SS7 MTP2 Users: MTP3
- SS7 SCCP Users: TCAP, RANAP, BSSAP, ...
Two main scenarios have been developed to use the different UALS for
IP Signalling Transport:
Draft Telephony Signalling AS October 2002
(1) Intercommunication of traditional Signalling transport nodes and
IP based nodes.
Traditional Telephony Traditional Telephony
Telephony Signalling Telephony Signalling
******* Signalling ********** over IP ******** ********* Signalling ********** over IP ********
* SEP *----------------* SG *--------------* ISEP * * SEP *----------------* SG *--------------* ISEP *
******* ********** ******** ********* ********** ********
+-----+ +------+ +-------+ +-------+
| SPU | | SPU | |SigProt| |SigProt|
+-----+ +----+----+ +------+ +-------+ +----+----+ +-------+
| | | |UAL | | UAL | | | | |UAL | | UAL |
| | | +----+ +------+ | | | +----+ +-------+
|CTSP | |CTSP|SCTP| | SCTP | | TTST | |TTST|SCTP| | SCTP |
| | | +----+ +------+ | | | +----+ +-------+
| | | | IP | | IP | | | | | IP | | IP |
+-----+ +---------+ +------+ +-------+ +---------+ +-------+
SEP: Signalling Endpoint SEP - Signalling Endpoint
SG: Signalling Gateway SG - Signalling Gateway
ISEP: IP Signalling Endpoint ISEP - IP Signalling Endpoint
SPU: Signalling Protocol User SigProt - Signalling Protocol
CTSP: Classical Telephony Signalling Protocol TTST - Traditional Telephony Signalling Transport
UAL: User Adaptation Layer UAL - User Adaptation Layer
SCTP: Stream Control Transport Protocol SCTP - Stream Control Transport Protocol
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 (2) Communication inside the IP network.
- Communication inside the IP networks.
Telephony Telephony
Signalling Signalling
******** over IP ******** ********* over IP *********
* ISEP *------------------* ISEP * * ISEP *------------------* ISEP *
******** ******** ********* *********
+------+ +------+ +-------+ +-------+
| SPU | | SPU | |SigProt| |SigProt|
+------+ +------+ +-------+ +-------+
| UAL | | UAL | | UAL | | UAL |
+------+ +------+ +-------+ +-------+
| SCTP | | SCTP | | SCTP | | SCTP |
+------+ +------+ +-------+ +-------+
| IP | | IP | | IP | | IP |
+------+ +------+ +-------+ +-------+
This is also referred to as IPSP communication. IPSP is the name This is also referred to as IPSP communication. IPSP is the name
given to the role that a UAL plays on an IP-based node. It stands
for IP Signalling Point.
4.1 IUA (ISDN Q.921 User Adaptation) Draft Telephony Signalling AS October 2002
This protocol supports both ISDN Primary Rate Access (PRA) as well of the role that an UAL plays on an IP-based node. It stands for
as Basic Rate Access (BRA) including the support for both IP Signalling Point.
point-to-point and point-to-multipoint modes of communication. This
support includes Facility Associated Signalling (FAS), Non-Facility The first scenario is applied for both types of signalling (access
and trunk signalling). On the other hand the peer to peer basis can
only be used for trunk signalling.
4.1 Access Signalling
The SIGTRAN WG have developed UALs to transport the following Access
Signalling protocols:
- ISDN Q.931
- V5.2
- DPNSS/DASS2
4.1.1 ISDN Q.931 over IP
UAL: IUA (ISDN Q.921 User Adaptation)
This document supports both ISDN Primary Rate Access (PRA) as well as
Basic Rate Access (BRA) including the support for both point-to-point
and point-to-multipoint modes of communication. This support
includes Facility Associated Signalling (FAS), Non-Facility
Associated Signalling (NFAS) and NFAS with backup D channel. Associated Signalling (NFAS) and NFAS with backup D channel.
It implements the client/server architecture. The default It implements the client/server architecture. The default orientation
orientation is for the SG to take on the role of server while the would be for the SG to take on the role of server while the ISEP is
ISEP is the client. The SCTP (and UDP/TCP) Registered User Port the client. The SCTP (and UDP/TCP) Registered User Port Number
Number Assignment for IUA is 9900. Assignment for IUA is 9900.
Examples of the upper layers to be transported are Q.931 and QSIG. Examples of the upper layers to be transported would be Q.931 and
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 an MGC, as defined in [RFC2719]. called MGC defined in [RFC2719].
Draft Telephony Signalling AS April 2002
****** ISDN ****** IP ******* ****** ISDN ****** IP *******
* EP *---------------* SG *--------------* MGC * *PBX *---------------* 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 |
+-----+ +-----+----+ +-----+ +-----+ +-----+----+ +-----+
Draft Telephony Signalling AS October 2002
NIF - Nodal Interworking Function NIF - Nodal Interworking Function
EP - ISDN End Point PBX - Private Branch Exchange
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 The SCTP (and UDP/TCP) Registered User Port Number Assignment for IUA
IUA is 9900. is 9900.
The value assigned by IANA for the Payload Protocol Identifier in The value assigned by IANA for the Payload Protocol Identifier in the
the SCTP Payload Data chunk is "1". SCTP Payload Data chunk is 1
4.2 V5UA (V5.2-User Adaptation) Layer 4.1.2 V5UA over IP
UAL: V5UA (V5.2-User Adaptation)
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 typically and ISDN primary rate access over a V5.2 interface. It is basically
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 |
+-----+ +-----+----+ +-----+ +-----+ +-----+----+ +-----+
AN - Access Network AN Access Network
NIF - Nodal Interworking Function NIF Nodal Interworking Function
LAPV5 Link Access Protocol for the V5 channel
Draft Telephony Signalling AS April 2002
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 Draft Telephony Signalling AS October 2002
the SCTP Payload Data chunk is "6".
4.3 DUA (DPNSS/DASS 2 User Adaptation) Layer The value assigned by IANA for the Payload Protocol Identifier in the
SCTP Payload Data chunk is "6".
The DUA is built on top of IUA and defines the necessary extensions 4.1.3 DPNSS/DASS2 over IP
to IUA for a DPNSS/DASS2 transport. DPNSS stands for Digital Private
UAL: DUA (DPNSS/DASS2 User Adaptation)
The DUA is built on top of IUA defining the necessary extensions to
IUA for a DPNSS/DASS2 transport. DPNSS stands for Digital Private
Network Signalling System and DASS2 for Digital Access Signalling 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 |
|DPNSS| |DPNSS+----+ +-----+ |DPNSS| |DPNSS+----+ +-----+
| 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 value assigned by IANA for the Payload Protocol Identifier in the
the SCTP Payload Data chunk is "TBD". SCTP Payload Data chunk is "TBD".
4.4 M2UA (SS7 MTP2 User Adaptation) Layer 4.2 Network Signalling
This protocol is typically used between a Signalling Gateway (SG) and The SIGTRAN WG have developed UALs to transport the following SS7
Media Gateway Controler (MGC). The SG will terminate up to MTP Level protocols:
- MTP2 Users: MTP3
- MTP3 Users: ISUP, TUP, SCCP
- SCCP Users: TCAP, RNSAP, RANAP, BSSAP, ...
4.2.1 MTP lvl3 over IP
Draft Telephony Signalling AS October 2002
UALs:
- M2UA (SS7 MTP2 User Adaptation)
- M2PA (SS7 MTP2-User Peer-to-Peer Adaptation)
4.2.1.1 M2UA (SS7 MTP2 User Adaptation)
M2UA protocol is mainly used between a Signalling Gateway (SG) and
Media Gateway Controller (MGC). The SG will terminate up to MTP Level
2 and the MGC will terminate MTP Level 3 and above. In other words, 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 the SG will transport MTP Level 3 messages over an IP network to a
MGC. MGC.
Draft Telephony Signalling AS April 2002 The only SS7 MTP2 User is MTP3 that is the protocol transported by
this UAL.
MTP3 and MTP3b are the only MTP2 Users that are transported by this
UAL.
The SG provides a interworking of transport functions with the IP The SG provides a interworking of transport functions with the IP
transport, to transfer the MTP2-User signalling messages with MTP2- transport, in order to transfer the MTP2-User signalling messages to
User at an application server(e.g. MGC). and from an Application Server (e.g. MGC) where the peer MTP2-
User protocol layer exists.
****** SS7 ****** IP ******* ****** SS7 ****** IP *******
*SEP *-----------* SG *-------------* MGC * *SEP *-----------* SG *-------------* MGC *
****** ****** ******* ****** ****** *******
+----+ +----+ +----+ +----+
|S7UP| |S7UP| |S7UP| |S7UP|
+----+ +----+ +----+ +----+
|MTP + |MTP | |MTP3| |MTP3|
| L3 | (NIF) |L3 | | | (NIF) | |
+----+ +----+----+ +----+ +----+ +----+----+ +----+
|MTP | |MTP |M2UA| |M2UA| | | | |M2UA| |M2UA|
| | | +----+ +----+
|MTP2| |MTP2|SCTP| |SCTP|
| | | +----+ +----+ | | | +----+ +----+
| L2 | | L2 |SCTP| |SCTP|
| L1 | | L1 +----+ +----+
| | | |IP | |IP | | | | |IP | |IP |
+----+ +---------+ +----+ +----+ +---------+ +----+
MGC - Media Gateway Controler MGC - Media Gateway Controler
SG - Signalling Gateway SG - Signalling Gateway
SEP - SS7 Signalling 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 Draft Telephony Signalling AS October 2002
the SCTP Payload Data chunk is "2".
4.5 M2PA (SS7 MTP2-User Peer-to-Peer Adaptation) Layer The value assigned by IANA for the Payload Protocol Identifier in the
SCTP Payload Data chunk is "2"
This protocol is used between SS7 Signalling Points using the MTP 4.2.1.2 M2PA (SS7 MTP2-User Peer-to-Peer Adaptation) Layer
M2PA protocol is used between SS7 Signalling Points employing the MTP
Level 3 protocol. The SS7 Signalling Points may also employ standard Level 3 protocol. The SS7 Signalling Points may also employ standard
SS7 links using the SS7 MTP Level 2 to provide transport of MTP SS7 links using the SS7 MTP Layer 2 to provide transport of MTP Layer
Level 3 signalling messages. 3 signalling messages.
Both configurations: interworking of SS7 and IP with SG and Both configurations: intercommunication of SS7 and IP with SG and
communication between ISEPs are possible. communication between ISEPs are possible.
Draft Telephony Signalling AS April 2002 Communication between two IP nodes:
******** IP ******** ******** IP ********
* IPSP *--------* IPSP * * IPSP *--------* IPSP *
******** ******** ******** ********
+------+ +------+ +------+ +------+
| TCAP | | TCAP | | TCAP | | TCAP |
+------+ +------+ +------+ +------+
| SCCP | | SCCP | | SCCP | | SCCP |
+------+ +------+ +------+ +------+
skipping to change at page 14, line 29 skipping to change at page 15, line 44
+------+ +------+ +------+ +------+
| SCTP | | SCTP | | SCTP | | SCTP |
+------+ +------+ +------+ +------+
| IP | | IP | | IP | | IP |
+------+ +------+ +------+ +------+
IP - Internet Protocol IP - Internet Protocol
IPSP - IP Signalling Point IPSP - IP Signalling Point
SCTP - Stream Control Transmission Protocol SCTP - Stream Control Transmission Protocol
Interconnection of SS7 and IP nodes:
Draft Telephony Signalling AS October 2002
******** 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 | | | | | M2PA | | M2PA |
+------+ +------+------+ +------+ | | | +------+ +------+
| MTP1 | | MTP1 | SCTP | | SCTP | | MTP2 | | MTP2 | SCTP | | SCTP |
| | | +------+ +------+ | | | +------+ +------+
| | | | IP | | IP | | | | | IP | | IP |
+------+ +------+------+ +------+ +------+ +------+------+ +------+
SEP - SS7 Signalling Endpoint SEP - SS7 Signalling Endpoint
These figures are only an example. Other configurations are These figures are only an example. Other configurations are possible.
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
to form an SG mated pair similar to the way STPs are provisioned in
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 value assigned by IANA for the Payload Protocol Identifier in the
the SCTP Payload Data chunk is "5". SCTP Payload Data chunk is TBD
Differences between M2PA and M2UA include:
Draft Telephony Signalling AS April 2002 4.2.1.3 Main differences between M2PA and M2UA:
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 necessarily an SS7 node and may not have a point code. M2UA: SG is not an SS7 node and has no 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.
Draft Telephony Signalling AS October 2002
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 4.3 MTP lvl3-Users (ISUP, TUP, SCCP) over IP
This adaptation layer supports the transport of any SS7 MTP3-User UAL: M3UA (SS7 MTP3 User Adaptation)
signalling such as TUP, ISUP and SCCP over IP using the services of
SCTP.
This protocol allows both: M3UA protocol supports the transport of any SS7 MTP3-User signalling
such as TUP, ISUP and SCCP over IP using the services of SCTP.
- Interworking of SS7 and IP nodes Interconnection 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 Signalling 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 Communication between two IP nodes:
Draft Telephony Signalling AS October 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 architecture. It is recommended It works using the client-server philosophy. ISEP is recommended to
that the ISEP act as the client and initiate SCTP associations with be client when talking with a SG. The reserved port by IANA is 2905
the SG. The port reserved by IANA is port number 2905. this is the to listen to possible client connections.
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 4.4 SCCP-Users over IP
This adaptation layer supports the transport of any SS7 SCCP-User UAL: SUA (SS7 SCCP User Adaptation)
signalling such as MAP, INAP, SMS, BSSAP, RANAP over IP using the
services of SCTP.
For message relaying, SUA should have the same timing constraints as SUA protocol supports the transport of any SS7 SCCP-User signalling
SCCP . For the end-to-end approach, SUA applications may have such as MAP, INAP, SMS, BSSAP, RANAP over IP using the services of
broader timing requirements (from 100 of milliseconds to hours) SCTP. SUA can support only non-call related signalling.
which allows the applications to guard themselves.
Possible configurations showed in the pictures below: SUA does not pose stringent timing constraints on SCTP due to the
fact that SUA applications have broad timing requirement (from 10 of
seconds to hours) which the applications guard themselves and the
timing supervision of the application is end-to-end, not hop-by-
hop(as with ISUP).
- Interworking of SS7 and IP Possible configurations are showed in the pictures below.
- IP Node to IP Node communication
Draft Telephony Signalling AS April 2002 - Interconnection of SS7 and IP:
******** SS7 *************** IP ******** Draft Telephony Signalling AS October 2002
* SEP *---------* *--------* *
* or * * SG * * ASP * ******** *************** ********
* SEP * IP * * IP * *
* or *---------* SG *--------* ASP *
* STP * * * * * * STP * * * * *
******** *************** ******** ******** *************** ********
+------ +------+ +------ +------+
| SUAP | | SUAP | | SUAP | | SUAP |
+------+ +------+------+ +------+ +------+ +------+------+ +------+
| SCCP | | SCCP | SUA | | SUA | | SCCP | | SCCP | SUA | | SUA |
+------+ +------+------+ +------+ +------+ +------+------+ +------+
| MTP3 | | MTP3 | | | | | | | | | | |
+------+ +------+ SCTP | | SCTP | | MTP3 | | MTP3 | SCTP | | SCTP |
| MTP2 | | MTP2 | | | | | | | | | | |
+------+ +------+------+ +------+ +------+ +------+------+ +------+
| L1 | | L1 | IP | | IP | | MTP2 | | MTP2 | IP | | IP |
+------+ +------+------+ +------+ +------+ +------+------+ +------+
SUAP - SCCP/SUA User Protocol (TCAP, for example) SUAP - SCCP/SUA User Protocol (TCAP, for example)
STP - SS7 Signalling Transfer Point STP - SS7 Signalling Transfer Point
******** IP ******** - IP Node to IP Node communication:
* *--------* *
* IPSP * * IPSP * ******** ********
* * IP * *
* IPSP *--------* IPSP *
* * * * * * * *
******** ******** ******** ********
+------+ +------+ +------+ +------+
| SUAP | | SUAP | | SUAP | | SUAP |
+------+ +------+ +------+ +------+
| SUA | | SUA | | SUA | | SUA |
+------+ +------+ +------+ +------+
| SCTP | | SCTP | | SCTP | | SCTP |
+------+ +------+ +------+ +------+
| IP | | IP | | IP | | IP |
+------+ +------+ +------+ +------+
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 connections. The payload protocol identifier for the SCTP DATA chunks
chunks is "4". is "4".
Draft Telephony Signalling AS April 2002 Draft Telephony Signalling AS October 2002
5 Security considerations 5 Security considerations
UALs are designated to carry signalling 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
skipping to change at page 18, line 40 skipping to change at page 20, 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.
[RFccccc] Coene, L., Tuexen, M., Verwimp, G., Loughney, J., Stewart, [RF3257] 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",
RFCzzzz, April 2002. RFC3257, April 2002.
[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.
[RFC3057] Morneault, K., Rengasami, S., Kalla, M., Sidebottom, G., [RFC3057] Morneault, K., Rengasami, S., Kalla, M., Sidebottom, G.,
"ISDN Q.921-User Adaptation Layer", RFC3057, February 2001.
[RFCxxxx] Morneault, K., Dantu, R., Sidebottom, G., George, T., Draft Telephony Signalling AS October 2002
Draft Telephony Signalling AS April 2002 "ISDN Q.921-User Adaptation Layer", RFC3057, February 2001.
[RFC3331] Morneault, K., Dantu, R., Sidebottom, G., George, T.,
Bidulock, B., Heitz , J., "Signaling System 7 (SS7) Message Transfer Bidulock, B., Heitz , J., "Signaling System 7 (SS7) Message Transfer
Part (MTP) 2 - User Adaptation Layer", RFCxxxx, May 2002. Part (MTP) 2 - User Adaptation Layer", RFC3331, September 2002.
[RFCyyyy] Sidebottom, G., Pastor-Balbas, J., Rytina, I., Mousseau, [RFC3332] Sidebottom, G., Pastor-Balbas, J., Rytina, I., Mousseau,
G., Ong, L., Schwarzbauer, H.J., Gradischnig, K., Morneault, K., G., Ong, L., Schwarzbauer, H.J., Gradischnig, K., Morneault, K.,
Kalla, M., Glaude, N., Bidulock, B., Loughney, J., "SS7 MTP3-User Kalla, M., Glaude, N., Bidulock, B., Loughney, J., "SS7 MTP3-User
Adaptation Layer (M3UA)", RFCyyyy, May 2002. Adaptation Layer (M3UA)", RFC3332, September 2002.
[RFCzzzz] Loughney, J., Sidebottom, G., Mousseau, G., Lorusso, S., [RFCzzzz] Loughney, J., Sidebottom, G., Mousseau, G., Lorusso, S.,
Coene, L., Verwimp, G., Keller, J., Escobar, F., Sully, W., Furniss, Coene, L., Verwimp, G., Keller, J., Escobar, F., Sully, W., Furniss,
S., Bidulock, B.,"SS7 SCCP-User Adaptation Layer (SUA)", RFCzzzz, S., Bidulock, B.,"SS7 SCCP-User Adaptation Layer (SUA)", RFCzzzz,
May 2002. May 2002.
[RFCwwww] George, T., Dantu, R., Kalla, M., Schwarzbauer, H.J., [RFCwwww] George, T., Dantu, R., Kalla, M., Schwarzbauer, H.J.,
Sidebottom, G., Morneault, K.,"SS7 MTP2-User Peer-to-Peer Adaptation Sidebottom, G., Morneault, K.,"SS7 MTP2-User Peer-to-Peer Adaptation
Layer", RFCwwww, June 2002. Layer", RFCwwww, June 2002.
skipping to change at page 19, line 47 skipping to change at page 22, line 5
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
Draft Telephony Signalling AS October 2002
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 Espana S.A. Email: j.javier.pastor@ericsson.com Ericsson Espana S.A. Email: j.javier.pastor@ericsson.com
C/ Ombu 3 C/ Retama 1
28045 Madrid 28045 Madrid
Spain Spain
Expires: August 2002 Expires: August 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
skipping to change at page 21, line 5 skipping to change at page 23, line 5
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 Draft Telephony Signalling AS October 2002
 End of changes. 

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