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Megaco/H.248
User's Guide
Version 3.18

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Chapters

- Introduction
  - Top of chapter
  - Scope and Purpose
  - Prerequisites
  - About This Manual
  - Where to Find More Information
- Architecture
  - Top of chapter
  - Network view
  - General
  - Single node config
  - Distributed config
  - Message round-trip call flow
- Running the stack
  - Top of chapter
  - Starting
  - MGC startup call flow
  - MG startup call flow
  - Configuring the Megaco stack
  - Initial configuration
  - Changing the configuration
  - The transaction sender
  - Segmentation of transaction replies
- Internal form and its encodings
  - Top of chapter
  - Internal form of messages
  - The different encodings
  - Configuration of Erlang distribution encoding module
  - Configuration of text encoding module(s)
  - Configuration of binary encoding module(s)
  - Handling megaco versions
  - Encoder callback functions
- Transport mechanisms
  - Top of chapter
  - Callback interface
  - Examples
- Implementation examples
  - Top of chapter
  - A simple Media Gateway Controller
  - A simple Media Gateway
- Megaco mib
  - Top of chapter
  - Intro
  - Statistics counters
  - Distribution
- Performance comparison
  - Top of chapter
  - Comparison of encoder/decoders
  - System performance characteristics
  - Description of encoders/decoders
  - Setup
  - Summary
- Testing and tools
  - Top of chapter
  - Tracing
  - Measurement and transformation

# 5 Transport mechanisms

### 5.1 Callback interface

The callback interface of the transport module contains several functions. Some of which are mandatory while others are only optional:

- send_message - Send a message. Mandatory

- block - Block the transport. Optional

  This function is usefull for flow control.

- unblock - Unblock the transport. Optional

For more detail, see the megaco_transport behaviour definition.

### 5.2 Examples

The Megaco/H.248 application contains implementations for the two protocols specified by the Megaco/H.248 standard; UDP, see megaco_udp, and TCP/TPKT, see megaco_tcp.