Nortel Networks Remote Gateway 50 manual Introduction, Codec negotiation

Page 50 of 258 Bandwidth Management

Introduction

CS 1000 supports Bandwidth Management on a network-wide basis so that voice quality can be managed between multiple Call Servers.

Bandwidth management allows for codec selection and bandwidth limitations to be placed on calls, depending on whether the calls are intrazone or interzone.

Adaptive Network Bandwidth Management is an enhancement of Bandwidth Management in which Quality of Service (QoS) metrics are used to automatically lower available bandwidth.

IMPORTANT!

Once all bandwidth is used, any additional calls are blocked or rerouted.

Keep this in mind when designing and implementing Network Bandwidth

Management.

Codec negotiation

Codec refers to the voice coding and compression algorithm used by DSPs. Each codec has different QoS and compression properties.

IP Peer Networking supports the per-call selection of codec standards, based on the type of call (interzone or intrazone). IP Peer Networking supports the following codecs (with supported payload sizes in parentheses, with the default value in bold):

•G.711 A/mu-law (10 ms, 20 ms, and 30 ms)

•G.729 A (10 ms, 20 ms, 30 ms, 40 ms, and 50 ms)

•G.729 AB (10 ms, 20 ms, 30 ms, 40 ms, and 50 ms)

•G.723.1 (30 ms) (though it can limit the number of DSP channels available)

•T.38 for fax

Note: The G.XXX series of codecs are standards defined by the International Telecommunications Union (ITU).

553-3001-207 Standard 2.00 January 2006