Cisco Systems 3600 manual VC-18Voice, Video, and Home Applications Configuration Guide

Configure IP Networks for Real-Time Voice Traffic

The important thing to remember is that QoS must be configured throughout your network—not just on the Cisco 3600 series devices running VoIP—to improve voice network performance. Not all QoS techniques are appropriate for all network routers. Edge routers and backbone routers in your network do not necessarily perform the same operations; the QoS tasks they perform might differ as well. To configure your IP network for real-time voice traffic, you need to take into consideration the functions of both edge and backbone routers in your network, then select the appropriate QoS tool or tools.

In general, edge routers perform the following QoS functions:

In general, backbone routers perform the following QoS functions:

Scalable QoS solutions require cooperative edge and backbone functions.

Note In a subsequent Cisco IOS release, we have implemented enhancements to improve QoS on low speed, wide-area links, such as ISDN, MLPPP, and Frame Relay running on edge routers. For more information about these enhancements, refer to the Cisco IOS Release 12.0(5)T “IP RTP” feature module.

Although not mandatory, some QoS tools have been identified as being valuable in fine-tuning your network to support real-time voice traffic. To configure your IP network for QoS using these tools, perform one or more of the following tasks:

Each of these components is discussed in the following sections.

VC-18Voice, Video, and Home Applications Configuration Guide