20002016 Ericsson AB. All Rights Reserved. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. Introduction Håkan Mattsson Håkan Mattsson Håkan Mattsson 2007-06-15 %VSN% megaco_intro.xml

Megaco/H.248 is a protocol for control of elements in a physically decomposed multimedia gateway, enabling separation of call control from media conversion. A Media Gateway Controller (MGC) controls one or more Media Gateways (MG).

This version of the stack supports version 1, 2 and 3 as defined by:

version 1 - RFC 3525 and H.248-IG (v10-v13)

version 2 - draft-ietf-megaco-h248v2-04 & H.248.1 v2 Corrigendum 1 (03/2004)

version 3:

prev3a - as defined by TD-33 (except segments)

prev3b - TD-33 updated to be backward compatible with v2 (except segments)

prev3c - As defined by ITU H.248.1 (09/2005) (except segments)

v3 - Full version 3 as defined by ITU H.248.1 (09/2005) (including segments)

The semantics of the protocol has jointly been defined by two standardization bodies:

IETF - which calls the protocol Megaco

ITU - which calls the protocol H.248
Scope and Purpose

This manual describes the Megaco application, as a component of the Erlang/Open Telecom Platform development environment. It is assumed that the reader is familiar with the Erlang Development Environment, which is described in a separate User's Guide.

Prerequisites

The following prerequisites is required for understanding the material in the Megaco User's Guide:

the basics of the Megaco/H.248 protocol

the basics of the Abstract Syntax Notation One (ASN.1)

familiarity with the Erlang system and Erlang programming

The application requires Erlang/OTP release R10B or later.

About This Manual

In addition to this introductory chapter, the Megaco User's Guide contains the following chapters:

Chapter 2: "Architecture" describes the architecture and typical usage of the application.

Chapter 3: "Internal form and its encodings" describes the internal form of Megaco/H.248 messages and its various encodings.

Chapter 4: "Transport mechanisms" describes how different mechanisms can be used to transport the Megaco/H.248 messages.

Chapter 5: "Debugging" describes tracing and debugging.
Where to Find More Information

Refer to the following documentation for more information about Megaco/H.248 and about the Erlang/OTP development system:

version 1, RFC 3525

old version 1, RFC 3015

Version 2 Corrigendum 1

version 2, draft-ietf-megaco-h248v2-04

TD-33 (Draft H.248.1 version 3)

H.248.1 version 3

the ASN.1 application User's Guide

the Megaco application Reference Manual

Concurrent Programming in Erlang, 2nd Edition (1996), Prentice-Hall, ISBN 0-13-508301-X.