ETSI TS 103 161-13 V1.1.1 (2011-10)

Access, Terminals, Transmission and Multiplexing (ATTM); Integrated Broadband Cable and Television Networks; IPCablecom 1.5; Part 13: Trunking Gateway Control Protocol - MGCP option

DTS/ATTM-003011-13

General Information

• Status: Published
• Publication Date: 26-Oct-2011
• Technical Committee: ATTM AT3 - Integrated broadband cable and television networks
• Current Stage: 12 - Completion
• Due Date: 31-Oct-2011
• Completion Date: 27-Oct-2011

Standards Content (Sample)

Technical Specification
Access, Terminals, Transmission and Multiplexing (ATTM);
Integrated Broadband Cable and Television Networks;
IPCablecom 1.5;
Part 13: Trunking Gateway Control Protocol - MGCP option

2 ETSI TS 103 161-13 V1.1.1 (2011-10)

Reference
DTS/ATTM-003011-13
Keywords
access, broadband, cable, IP, multimedia, PSTN
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: [phone]  Fax: [phone]

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

Important notice
Individual copies of the present document can be downloaded from:
http://www.etsi.org
The present document may be made available in more than one electronic version or in print. In any case of existing or
perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF).
In case of dispute, the reference shall be the printing on ETSI printers of the PDF version kept on a specific network drive
within ETSI Secretariat.
Users of the present document should be aware that the document may be subject to revision or change of status.
Information on the current status of this and other ETSI documents is available at
http://portal.etsi.org/tb/status/status.asp
If you find errors in the present document, please send your comment to one of the following services:
http://portal.etsi.org/chaircor/ETSI_support.asp
Copyright Notification
No part may be reproduced except as authorized by written permission.
The copyright and the foregoing restriction extend to reproduction in all media.

© European Telecommunications Standards Institute 2011.
All rights reserved.
TM TM TM
DECT , PLUGTESTS , UMTS and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members.
TM
3GPP and LTE™ are Trade Marks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
GSM® and the GSM logo are Trade Marks registered and owned by the GSM Association.
ETSI
3 ETSI TS 103 161-13 V1.1.1 (2011-10)
Contents
Intellectual Property Rights . 7
Foreword . 7
1 Scope . 9
2 References . 9
2.1 Normative references . 9
2.2 Informative references . 11
3 Definitions and abbreviations . 11
3.1 Definitions . 11
3.2 Abbreviations . 11
4 Void . 13
5 Technical Overview . 13
6 Introduction . 14
6.1 Relation with Other IPCablecom Standards . 15
6.2 Relation to RFC 3435 and ABNF Grammar . 15
7 Media Gateway Control Interface (MGCI) . 16
7.1 Model and Naming Conventions . 16
7.1.1 Endpoint Names . 16
7.1.1.1 Trunking Gateway Endpoint Names . 17
7.1.1.1.1 Trunk Circuit Endpoints . 17
7.1.2 Call Names. 19
7.1.3 Connection Names . 19
7.1.4 Names of Media Gateway Controllers and Other Entities . 19
7.1.5 Digit Maps . 20
7.1.6 Events and Signals . 20
7.2 SDP Use . 22
7.3 Gateway Control Functions . 22
7.3.1 NotificationRequest . 24
7.3.2 Notifications . 29
7.3.3 CreateConnection . 29
7.3.4 ModifyConnection . 34
7.3.5 DeleteConnection (From the Media Gateway Controller) . 35
7.3.6 DeleteConnection (From the Trunking gateway) . 37
7.3.7 DeleteConnection (Multiple Connections From the Media Gateway Controller) . 37
7.3.8 Auditing . 38
7.3.8.1 AuditEndPoint . 38
7.3.8.2 AuditConnection . 40
7.3.9 Restart in Progress . 41
7.4 States, Failover and Race Conditions . 43
7.4.1 Recaps and Highlights . 43
7.4.2 Retransmission and Detection of Lost Associations . 43
7.4.3 Race Conditions . 46
7.4.3.1 Quarantine list . 46
7.4.3.2 Explicit detection . 50
7.4.3.3 Transactional Semantics . 50
7.4.3.4 Ordering of commands and treatment of disorder . 51
7.4.3.5 Fighting the restart avalanche . 52
7.4.3.6 Disconnected Endpoints . 53
7.4.3.7 Call Agent Handling of Disconnected Endpoints . 55
7.5 Return Codes and Error Codes . 56
7.6 Reason Codes . 58
7.7 Use of Local Connection Options and Connection Descriptors . 58
7.7.1 RFC 2833 Negotiation . 60
ETSI
4 ETSI TS 103 161-13 V1.1.1 (2011-10)
7.7.2 Remote IP and Port Negotiation . 60
7.7.3 LCO use when the FXR package is used without the VBD package . 61
7.7.3.1 fxr/fx:gw . 61
7.7.3.2 fxr/fx:t38;off. 61
7.7.3.3 fxr/fx:t38 . 62
7.7.3.4 fxr/fx:t38-loose . 62
7.7.3.5 Other Options . 62
7.7.4 LCO with FXR and VBD being used by MGC at same time . 63
7.7.5 LCO format for V.152 and 2198 Redundancy use . 64
8 Media Gateway Control Protocol . 65
8.1 General Description . 65
8.2 Command Header . 66
8.2.1 Command Line . 66
8.2.1.1 Requested Verb Coding . 66
8.2.1.2 Transaction Identifiers . 66
8.2.1.3 Endpoint, Media Gateway Controller and NotifiedEntity Name Coding . 67
8.2.1.4 Protocol Version Coding . 67
8.2.2 Parameter Lines . 68
8.2.2.1 Response Acknowledgement . 69
8.2.2.2 RequestIdentifier . 69
8.2.2.3 Local Connection Options . 70
8.2.2.4 Capabilities. 71
8.2.2.5 Connection Parameters . 72
8.2.2.6 Reason Codes . 72
8.2.2.7 Connection Mode . 73
8.2.2.8 Event/Signal Name Coding . 73
8.2.2.9 RequestedEvents . 74
8.2.2.10 SignalRequests . 74
8.2.2.11 ObservedEvents . 75
8.2.2.12 RequestedInfo . 75
8.2.2.13 QuarantineHandling . 76
8.2.2.14 DetectEvents . 76
8.2.2.15 EventStates . 76
8.2.2.16 RestartMethod . 76
8.2.2.17 VersionSupported . 76
8.2.2.18 Call Identifier . 76
8.2.2.19 Connection Identifier . 76
8.2.2.20 MaxMGCPDatagram . 77
8.3 Response Header Formats . 77
8.3.1 CreateConnection . 78
8.3.2 ModifyConnection . 79
8.3.3 DeleteConnection . 79
8.3.4 NotificationRequest . 79
8.3.5 Notify . 79
8.3.6 AuditEndpoint . 79
8.3.7 AuditConnection . 80
8.3.8 RestartInProgress . 80
8.4 Session Description Encoding . 80
8.4.1 Use of SDP . 81
8.4.2 SDP Parameters Common to both Audio (m=audio media line) and Image (m=image media line)
Service Use . 81
8.4.2.1 Protocol Version (v=) . 81
8.4.2.2 Session Name (s=) . 82
8.4.2.3 Session and Media Information (i=) . 82
8.4.2.4 URI (u=) . 82
8.4.2.5 E-Mail Address and Phone Number (e=, p=) . 82
8.4.2.6 Connection Data (c=) . 82
8.4.2.7 Bandwidth (b=) . 83
8.4.2.8 Time, Repeat Times and Time Zones (t=, r=, z=) . 83
8.4.2.9 Attributes (a=) . 83
8.4.3 SDP Audio Service Use . 85
ETSI
5 ETSI TS 103 161-13 V1.1.1 (2011-10)
8.4.3.1 Encryption Keys . 85
8.4.3.2 Attributes (a=) . 85
8.4.3.3 Media Announcements (m=) . 87
8.4.4 SDP Image Service Use for T.38 . 87
8.4.4.1 Encryption Keys: . 87
8.4.4.2 Attributes (a=) . 88
8.4.4.3 Media Announcements (m=) . 89
8.5 Transmission Over UDP . 90
8.5.1 Reliable Message Delivery . 90
8.5.2 Retransmission Strategy . 90
8.5.3 Maximum Datagram Size, Fragmentation and Reassembly . 91
8.6 Piggy-Backing . 91
8.7 Transaction identifiers and three ways handshake . 92
8.8 Provisional Responses . 93
9 Security. 94
Annex A (normative): Event Packages . 95
A.1 ISUP Trunk Package . 95
A.2 MF FGD Operator Services Package . 98
A.3 MF Terminating Protocol Package . 101
A.4 FAX Package . 103
A.5 VoIP Metrics Package . 103
A.6 Vbd and GPMD packages . 104
Annex B (informative): Mode Interactions . 105
Annex C (informative): Example Command Encodings . 107
C.1 NotificationRequest . 107
C.2 Notify . 107
C.3 CreateConnection . 107
C.4 ModifyConnection . 109
C.5 DeleteConnection (From the Media Gateway Controller) . 110
C.6 DeleteConnection (From the Trunking gateway) . 110
C.7 DeleteConnection (Multiple Connections From the Media Gateway Controller). 110
C.8 AuditEndpoint . 111
C.9 AuditConnection . 111
C.10 RestartInProgress . 112
Annex D (informative): Example Call Flow . . 114
Annex E (normative): Endpoint Requirements . 117
E.1 Connection Modes Supported . 117
Annex F (informative): Compatibility Information . 118
F.1 NCS Compatibility . 118
F.2 MGCP Compatibility . 118
Annex G (normative): ABNF Grammar for TGCP . 120
Annex H (normative): Electronic Surveillance . 131
ETSI
6 ETSI TS 103 161-13 V1.1.1 (2011-10)
H.1 MGC . 131
H.2 MG . . 131
Annex G (informative): Bibliography . 134
History . 135

ETSI
7 ETSI TS 103 161-13 V1.1.1 (2011-10)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Access, Terminals, Transmission
and Multiplexing (ATTM).
The present document is part 13 of a multi-part IPCablecom 1.5 deliverable covering the Digital Broadband Cable
Access to the Public Telecommunications Network; IP Multimedia Time Critical Services, as identified below:
Part 1: "Overview";
Part 2: "Architectural framework for the delivery of time critical services over Cable Television Networks using
Cable Modems";
Part 3: "Audio Codec Requirements for the Provision of Bi-Directional Audio Service over Cable Television
Networks using Cable Modems";
Part 4: "Network Call Signalling Protocol";
Part 5: "Dynamic Quality of Service for the Provision of Real Time Services over Cable Television Networks
using Cable Modems";
Part 6: "Event Message Specification";
Part 7: "Media Terminal Adapter (MTA Management Information Base (MIB)";
Part 8: "Network Call Signalling (NCS) MIB Requirements";
Part 9: "Security";
Part 10: "Management Information Base (MIB) Framework";
Part 11: "Media terminal adapter (MTA) device provisioning";
Part 12: "Management Event Mechanism";
Part 13: "Trunking Gateway Control Protocol - MGCP option";
Part 14: "Embedded MTA Analog Interface and Powering Specification"
Part 15: "Analog Trunking for PBX Specification";
Part 16: "Signalling for Call Management Server";
Part 17: "CMS Subscriber Provisioning Specification";
Part 18: "Media Terminal Adapter Extension MIB";
Part 19: "IPCablecom Audio Server Protocol Specification - MGCP option";
Part 20: "Management Event MIB Specification";
ETSI
8 ETSI TS 103 161-13 V1.1.1 (2011-10)
Part 21: "Signalling Extension MIB Specification".
NOTE 1: Additional parts may be proposed and will be added to the list in future versions.
NOTE 2: The choice of a multi-part format for this deliverable is to facilitate maintenance and future
enhancements.
ETSI
9 ETSI TS 103 161-13 V1.1.1 (2011-10)
1 Scope
The present document is part of the IPCablecom suite of specifications. The document is based on MGCP 1.0 [1] an
IETF Informational RFC.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
[1] IETF RFC 3435: "Media Gateway Control Protocol (MGCP) Version 1.0", January 2003.
[2] IETF RFC 1889: "RTP: A Transport Protocol for Real-Time Applications", January 1996.
[3] IETF RFC 1890: "RTP Profile for Audio and Video Conferences with Minimal Control",
January 1996.
[4] IETF RFC 2327: "SDP: Session Description Protocol", April 1998.
[5] Stevens, W. Richard: "TCP/IP Illustrated, Volume 1, The Protocols", Addison-Wesley, 1994.
[6] Telcordia GR-317: "LSSGR: Switching System Generic Requirements for Call Control Using the
Integrated Services Digital Network User Part (ISDNUP)", November 2007.
[7] Telcordia TR-NPL-000258: "Compatibility Information for Feature Group D Switched Access
Service", Issue 1, October 1985.
NOTE: Available at: http://telecom-info.telcordia.com/site-cgi/ido/docs.cgi?ID=SEARCH&DOCUMENT=TR-
NPL-000258&.
[8] Telcordia GR-531: " LSSGR: Interoffice, FSDs 25-05-0903, 25-06-0501, 25-06-0502,
25-06-0506", Issue 1, June 2000.
NOTE: Available at: http://telecom-info.telcordia.com/site-
cgi/ido/docs.cgi?ID=274635926SEARCH&KEYWORDS=&TITLE=&DOCUMENT=GR-
531&DATE=&CLASS=&COUNT=1000&REF=REF.
[9] Telcordia GR-506: "Signaling for Analog Interfaces", December 2006.
[10] Telcordia GR-1176: "OSSGR: Custom Call Handling Features (FSD 80 Series)", April 1999.
NOTE: Available at: http://telecom-info.telcordia.com/site-
cgi/ido/docs.cgi?ID=273254321SEARCH&KEYWORDS=&TITLE=&DOCUMENT=GR-
1176&DATE=&CLASS=&COUNT=1000&REF=REF#ORD.
[11] ETSI TS 103 161-3: "Access, Terminals, Transmission and Multiplexing (ATTM); Integrated
Broadband Cable and Television Networks; IPCablecom 1.5; Part 3: Audio Codec Requirements
for the Provision of Bi-Directional Audio Service over Cable Television Networks using Cable
Modems".
ETSI
10 ETSI TS 103 161-13 V1.1.1 (2011-10)
[12] ETSI ETSI TS 103 161-9: "Access, Terminals, Transmission and Multiplexing (ATTM);
Integrated Broadband Cable and Television Networks; IPCablecom 1.5; Part 9: Security".
[13] ETSI TS 103 161-4: "Access, Terminals, Transmission and Multiplexing (ATTM); Integrated
Broadband Cable and Television Networks; IPCablecom 1.5; Part 4: Network Call Signalling
Protocol".
[14] IETF RFC 2821: "Simple Mail Transfer Protocol", April 2001.
[15] IEFT RFC 2234: "Augmented BNF for Syntax Specifications: ABNF", November 1997.
[16] ITU-T Recommendation T.30: "Procedures for Document Facsimile Transmission in the General
Switched Telephone Network", September 2005.
[17] ITU-T Recommendation V.8: "Procedures for starting sessions of data transmission over the
public switched telephone network", November 2000.
[18] ITU-T Recommendation V.18: "Operational and interworking requirements for DCEs operating in
the text telephone mode", November 2000.
[19] ITU-T Recommendation V.21: "300 bits per second duplex modem standardized for use in the
general switched telephone network", November 1988.
[20] ITU-T Recommendation V.25: "Automatic answering equipment and general procedures for
automatic calling equipment on the general switched telephone network including procedures for
disabling of echo control devices for both manually and automatically established calls",
October 1996.
[21] IETF RFC 2045: "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet
Message Bodies", November 1996.
[22] IETF RFC 2833, H. Schulzrinne, S. Petrack: "RTP Payload for DTMF Digits, Telephony Tones
and Telephony Signals", May 2000.
[23] IETF RFC 2474: "Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6
Headers", December 1998.
[24] ITU-T Recommendation T.38: "Procedures for real-time Group 3 facsimile communication over
IP networks", September 2010.
[25] IETF RFC 2198: "RTP Payload for Redundant Audio Data", September 1997.
[26] IETF RFC 3407: "Session Description Protocol (SDP) Simple Capability Declaration",
October 2002.
[27] ITU-T Recommendation V.152: "Procedures for supporting voice-band data over IP networks",
September 2010.
[28] IETF RFC 5347: "Media Gateway Control Protocol Fax Package", October 2008.
[29] IETF RFC 821: "Simple Mail Transfer Protocol".
[30] IETF RFC 3660: "Basic Media Gateway Control Protocol (MGCP) Packages".
[31] IETF RFC 2373: "IP Version 6 Addressing Architecture".
[32] IETF draft-auerbach-mgcp-rtcpxr-00: "Media Gateway Control Protocol VoIP RTCP-XR Metrics
Package".
NOTE: Available at http://docbox.etsi.org/Reference/IETF/Drafts/draft-auerbach-mgcp-rtcpxr-00.PDF.
[33] IETF draft-stone-mgcp-vbd-00: "Media Gateway Control Protocol Voiceband Data Package and
General Purpose Media Descriptor Parameter Package".
NOTE: Available at http://docbox.etsi.org/Reference/IETF/Drafts/draft-stone-mgcp-vbd-00.PDF.
ETSI
11 ETSI TS 103 161-13 V1.1.1 (2011-10)
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI TS 102 836-1 (V1.1.1): "Access, Terminals, Transmission and Multiplexing (ATTM);
Lawful Interception (LI); Part 1: Interception of IP Telephony Service on Cable Operator's
Broadband IP Network: Internal Network Interfaces".
[i.2] IETF RFC 1034/STD 0013: "Domain Names - Concepts and Facilities", November 1987.
[i.3] IETF RFC 3264: "An Offer/Answer Model with Session Description Protocol (SDP)", June 2002.
[i.4] IETF RFC 1122/STD003: "Requirements for Internet Hosts - Communication Layers, STD",
October 1989.
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
authentication: process of verifying the claimed identity of an entity to another entity
endpoint: terminal, gateway or Multipoint Conference Unit (MCU)
gateway: devices bridging between the IPCablecom IP Voice Communication world and the PSTN
NOTE: Examples are the Media Gateway, which provides the bearer circuit interfaces to the PSTN and
transcodes the media stream, and the Signalling Gateway, which sends and receives circuit switched
network signalling to the edge of the IPCablecom network.
header: protocol control information located at the beginning of a protocol data unit
jitter: variability in the delay of a stream of incoming packets making up a flow such as a voice communication
key: mathematical value input into the selected cryptographic algorithm
latency: time, expressed in quantity of symbols, taken for a signal element to pass through a device
network management: functions related to the management of data across the network
trunk: analogue or digital connection from a circuit switch that carries user media content and may carry voice
signalling (M , R , etc.)
F 2
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AAD Average Acknowledgement Delay
ABNF Augmented Backus-Naur Form
AC Access Code
ACM Accumulated Call Meter
ANI Access Network Interface
ANM Answer Message
ANS Answer Tone
API Application Program Interface
AT Access Tandem
ATM Asynchronous Transfer Mode
AV Audio Video
BLV Busy-Line Verification
ETSI
12 ETSI TS 103 161-13 V1.1.1 (2011-10)
BNF Backus Naur Form
BR Brief
CA Call Agent
CAS Channel Associated Signalling
CCC Call Content Connection
CLEC Local Exchange Carrier
CM Cable Modem
CMS Call Management Server
CMTS Cable Modem Termination System
CODEC COder-DECoder
COT Continuity Test
CRCX Create Connection
DNS Domain Name Service
DQoS Dynamic Quality-of-Service
DSCP DiffServ Code Point
DTMF Dual-tone Multi Frequency (tones)
EAEO Equal Access End Office/Access Tandem
ECN Exchange Connection Number
ETSI European Telecommunications Standards Institute
FEC Forward Error Correction
FGC Feature Group C Signalling
FGD Feature Group D signalling
FIFO First-In-First-Out
HFC Hybrid Fibre/Coaxial
IANA Internet Assigned Numbered Authority
ID IDentifier
IETF Internet Engineering Task Force
IP Internet Protocol
IPDC IP Device Control
IPsec Internet Protocol Security
ISDN Integrated Services Digital Network
ISUP ISDN User Part
ITU International Telecommunication Union
ITU-T International Telecommunication Union-Telecommunication Standardization Sector
LATA Local Access and Transport Area
LC Local Connection Descriptor
LCD Local Control Descriptor
LCO Local Connection Options
LEC Local Exchange Carrier
LSSGR LATA Switching Systems Generic Requirements
MC Multipoint Controller
MCU Multipoint Conference Unit
MDCX Modify Connection
MF Multi-Frequency
MG Media Gateway
MGC Media Gateway Controller
MGCI Media Gateway Control Interface MGCI
MGCP Media Gateway Control Protocol
MIB Management Information Base
MTA Multimedia Terminal Adapter
MWD Maximum Waiting Delay
NA Not Applicable
NCS Network Call Signalling
NTP Network Time Protocol
OI Operator Interrupt
OSS Operations Systems Support
PBX Private Branch Exchange
PR Packets Received
PSTN Public Switched Telephone Network
RC Remote Connection Descriptor
RCD Remote Connection Description
REL Release message
ETSI
13 ETSI TS 103 161-13 V1.1.1 (2011-10)
RFC Request for Comments
RLC Release Complete message
RPC Remote Procedure Call
RTCP Real-Time Control Protocol
RTO Retransmission Timeout
RTP Real-time Transport Protocol
RTSP Real-time Streaming Protocol
SDP Session Description Protocol
SG Signalling Gateway
SIP Session Initiation Protocol
SNMP Simple Network Management Protocol
SS7 Signalling System number 7
SSRC Synchronization Source Identifier
TCP Transmission Control Protocol
TDD Telecom Devices for the Deaf
TGCP Trunking Gateway Control Protocol
TGW Telephony Gateway
TO Time Out
TTL Time To Live
UDP User Datagram Protocol
VAD Voice Activity Detection
VoIP Voice-over-IP
4 Void
5 Technical Overview
The present document describes an IPCablecom profile of an application programming interface called a Media
Gateway Control Interface (MGCI) and a corresponding protocol (MGCP) for controlling voice-over-IP (VoIP) PSTN
Gateways from external call control elements. The MGCP assumes a call control architecture where the call control
"intelligence" is outside the gateways and handled by external call control elements. The IPCablecom profile as
described in the present document will be referred to as the IPCablecom Trunking Gateway Control Protocol (TGCP).
The present document is based on the IPCablecom Network-Based Call Signalling (NCS) 1.5 specification [13], the
Media Gateway Control Protocol (MGCP) 1.0 IETF RFC [1] (which was the result of a merge of the IETF draft of
Simple Gateway Control Protocol and the IETF draft of IP Device Control (IPDC) family of protocols), and input
generated by the IPCablecom PSTN Gateway focus team.
The present document, which defines the IPCablecom TGCP Protocol, constitutes a document that is independent of
MGCP in order to provide a stable reference document while meeting current time-to-market demands for such a
reference. It is the intent of the present document to be as closely aligned with NCS and MGCP 1.0 as possible for the
IPCablecom environment, in order to avoid developing multiple protocols to solve the same problem. This goal has
been and continues to be pursued through cooperation with the authors of the NCS and MGCP specifications. The
TGCP profile of MGCP, however, is strictly and solely defined by the contents of the present document.
This TGCP profile of MGCP, which will be referred to as the PSTN Trunking Gateway Call Signalling Protocol 1.0,
TGCP 1.0, the TGCP profile, or simply TGCP in the present document, has been modified from the MGCP 1.0 IETF
RFC [1] in the following ways:
• The TGCP protocol only aims at supporting IPCablecom voice-over-IP PSTN Gateways. The TGCP protocol
supports voice-over-IP PSTN Gateways as defined by IPCablecom. Functionality present in the MGCP 1.0
protocol, which was superfluous to TGCP, has been removed.
• The TGCP protocol contains extensions and modifications to MGCP. IPCablecom-specific requirements are
addressed in TGCP. However, the MGCP architecture, and all of the MGCP constructs relevant to PSTN
Gateways, have been preserved in TGCP.
ETSI
14 ETSI TS 103 161-13 V1.1.1 (2011-10)
• The TGCP protocol contains minor simplifications from MGCP 1.0. Where several choices were available,
and not necessarily needed for a PSTN Gateway in the IPCablecom environment, some simplifications have
been made for trunking gateway implementations.
Although MGCP is not TGCP, and TGCP is not MGCP, the names MGCP and TGCP will be used interchangeably in
the present document since the present document is based on MGCP. Unless otherwise stated or inferable by context,
the word MGCP shall be taken to mean the TGCP profile of MGCP in the present document.
TGCP is designed to meet the protocol requirements for the Media Gateway Controller to Media Gateway interface
defined in the IPCablecom architecture.
6 Introduction
The present document describes the TGCP profile of an application programming interface (MGCI) and a
corresponding protocol (MGCP) for controlling trunking gateways from external call control elements.
A trunking gateway is a network element that provides analogue, emulated analogue, or digital bearer and channel-
associated signalling trunk circuit access to a voice-over-IP (VoIP) network.
Trunking gateways are used for interfacing to the PSTN and as such are expected to adhere to the relevan
...