A Telephony Gateway REgistration Protocol (TGREP)
RFC 5140
Network Working Group M. Bangalore
Request for Comments: 5140 R. Kumar
Category: Standards Track J. Rosenberg
Cisco
H. Salama
Citex Software
D.N. Shah
Moowee Inc.
March 2008
A Telephony Gateway REgistration Protocol (TGREP)
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Abstract
This document describes the Telephony Gateway Registration Protocol
(TGREP) for registration of telephony prefixes supported by telephony
gateways and soft switches. The registration mechanism can also be
used to export resource information. The prefix and resource
information can then be passed on to a Telephony Routing over IP
(TRIP) Location Server, which in turn can propagate that routing
information within and between Internet Telephony Administrative
Domains (ITADs). TGREP shares a lot of similarities with the TRIP
protocol. It has similar procedures and finite state machine for
session establishment. It also shares the same format for messages
and a subset of attributes with TRIP.
Bangalore, et al. Standards Track [Page 1]
RFC 5140 TGREP March 2008
Table of Contents
1. Introduction ....................................................3
2. Terminology and Definitions .....................................5
3. TGREP: Overview of Operation ....................................6
4. TGREP Attributes ................................................7
4.1. TotalCircuitCapacity Attribute .............................8
4.2. AvailableCircuits Attribute ................................9
4.3. CallSuccess Attribute .....................................10
4.4. Prefix Attributes .........................................12
4.5. TrunkGroup Attribute ......................................13
4.6. Carrier Attribute .........................................15
5. TrunkGroup and Carrier Address Families ........................16
5.1. Address Family Syntax .....................................17
6. Gateway Operation ..............................................18
6.1. Session Establishment .....................................18
6.2. UPDATE Messages ...........................................19
6.3. KEEPALIVE Messages ........................................19
6.4. Error Handling and NOTIFICATION Messages ..................19
6.5. TGREP Finite State Machine ................................19
6.6. Call Routing Databases ....................................19
6.7. Multiple Address Families .................................20
6.8. Route Selection and Aggregation ...........................20
7. LS/Proxy Behavior ..............................................20
7.1. Route Consolidation .......................................22
7.2. Aggregation ...............................................23
7.3. Consolidation versus Aggregation ..........................23
8. Security Considerations ........................................23
9. IANA Considerations ............................................24
9.1. Attribute Codes ...........................................24
9.2. Address Family Codes ......................................24
10. Acknowledgments ...............................................25
11. References ....................................................25
11.1. Normative References .....................................25
11.2. Informative References ...................................26
Bangalore, et al. Standards Track [Page 2]
RFC 5140 TGREP March 2008
1. Introduction
It is assumed that the reader of this document is familiar with TRIP
[2, 12]. In typical Voice over IP (VoIP) networks, Internet
Telephony Administrative Domains (ITADs) will deploy numerous
gateways for the purposes of geographical diversity, capacity, and
redundancy. When a call arrives at the domain, it must be routed to
one of those gateways. Frequently, an ITAD will break its network
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