1 Introduction

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 - 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

1.1  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.

1.2  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.

1.3  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.

1.4  Where to Find More Information

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