MGCP CAS Packages
RFC 3064

Document Type RFC - Informational (February 2001; No errata)
Last updated 2013-03-02
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Network Working Group                                          B. Foster
Request for Comments: 3064                                 Cisco Systems
Category: Informational                                    February 2001

                           MGCP CAS Packages

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

Abstract

   This document contains a collection of media gateway Channel
   Associated Signaling (CAS) packages for R1 CAS, North American CAS,
   CAS PBX interconnect as well as basic FXO support.  Included are six
   packages.  The "MS" package covers MF single stage dialing trunks.
   This includes wink start and immediate start PBX DID/DOD trunks as
   well as basic R1 and Feature Group D (FGD) Terminating protocol [3].
   The "DT "package covers immediate start and basic DTMF and dial-pulse
   trunks and the "BL" package covers the interface to a basic PBX
   (digital or FXS interface).  In addition to the Terminating protocol,
   there are three other FGD protocols described in [3].  These include
   EAIN and EANA which is covered by the enclosed "MD" package and the
   Operator Service Signaling protocol which is handled by the "MO"
   package.  Support for basic FXO interconnect is provided by "DO"
   package.

Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC-2119.

IESG Note:

   This document is being published for the information of the
   community.  It describes a protocol that is currently being deployed
   in a number of products.  Implementers should be aware of
   developments in the IETF Megaco Working Group and ITU SG16 who are
   currently working on a potential successor to this protocol.

Foster                       Informational                      [Page 1]
RFC 3064                   MGCP CAS Packages               February 2001

Table of Contents

   1.0.Introduction ................................................  3
   1.1. Functional Partitioning ....................................  3
   1.2. CAS Trunk Types ............................................  4
   1.2.1. "MS" Package .............................................  5
   1.2.2. "DT" Package .............................................  5
   1.2.3. "BL" Package .............................................  6
   1.2.4. "DO" Package .............................................  6
   1.2.5. "MD" Package .............................................  6
   1.2.6. "MO" Package .............................................  7
   2.0. Event Packages .............................................  7
   2.1. Events and Signals for the "MS" package ....................  9
   2.2. Events and Signals for the "DT" package .................... 10
   2.3. Events and Signals for the "BL" package (Basic PBX) ........ 10
   2.4. Events and Signals for the "DO" package .................... 11
   2.5. Events and Signals for the "MD" package .................... 12
   2.6. Events and Signals for the "MO" package .................... 13
   2.7. Event and Signal Descriptions .............................. 13
   3.0. Hook-State Signals and Events .............................. 23
   3.1. Overview of Approach ....................................... 23
   3.2. Suspend/Resume Processing .................................. 23
   3.3. Control over Disconnect for E911 ........................... 24
   3.3. Release and Release Complete ............................... 24
   3.4. Blocking CAS Trunks ........................................ 26
   3.5. Summary of Hook-State Events ............................... 26
   4.0. Glare Handling ............................................. 27
   4.1. Glare on MF Bi-directional Wink-start Trunks ............... 27
   4.2. Glare Handling - Basic PBX Trunks .......................... 27
   5.0. Example Call Flows ......................................... 28
   5.1. PBX to PBX ("MS", "DT, and "BL" packages)................... 28
   5.1.1. Call Setup Flows ......................................... 28
   5.1.2. Call Tear-Down ........................................... 34
   5.1.2.1. Origination End Initiates the Release .................. 35
   5.1.2.2. Termination End Initiates the Release .................. 38
   5.2. Example Call Flows - "DO" package .......................... 40
   5.2.1. Call Setup Flows ......................................... 40
   5.2.2. Call Tear-Down ........................................... 42
   5.3. Example Call Setup - "MD" Package .......................... 44
   5.4. Example Call Setup - "MO" Package .......................... 51
   Acknowledgements ................................................ 54
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