The Avaya Systems Interoperability Test Lab has a large deployment of Cisco network infrastructure equipment and provides updated documentation for many configurations of Avaya Communication Manager and Cisco routers. (Review Application Notes on avaya.co.uk. Go to Do Your Research/Resource Library/Application Notes.) Most enterprises need assurances as to the tangible benefits to be gained by integrating components from different vendors. Discussion is mostly around features, functionality, and integration requirements. By integrating Avaya Business Communications Applications into a Cisco data network, the full 700+ Communication Manager features become available. There are two general categories of features: - Features that users directly take advantage of, including Extension to Cellular, Whisper Page, and Bridged Call Appearances
- Features that administrators take advantage of, such as Stateful Failover Between Servers, and Enterprise Survivability
Your Avaya representative or BusinessPartner can help define which features will make the biggest impact on your business. The most important requirement for any deployment of IP telephony is that the network (Cisco for this discussion) needs to provide end-to-end Quality of Service (QoS) based on DiffServ Code Point (DCSP) and/or COS (Layer 2 Class of Service). Avaya servers, gateways, and endpoints can tag packets using combinations of DSCP and/or COS. Tagging is performed independently for signalling and bearer (voice and/or video), allowing for a granular configuration. Tagging can also be configured independently for each location, although it is recommended that the same tagging scheme be uniform throughout the enterprise. In addition Avaya supports RSVP, although it is not commonly used today. This assures that the voice communications will work over any data network that supports these tactics for QoS, like Cisco. This does not mean a crazy router configuration, but rather a similar configuration to what is used for Cisco’s IP telephony. Avaya recommends using Low Latency Queuing (LLQ) for WAN circuits, which is what Cisco recommends. Since our CODECs are the same, and based on the Real Time Protocol (RTP) standard, taking advantage of Compressed RTP (cRTP) on lower speed WAN circuits is supported. There are many existing companies that have implemented Cisco/Avaya interoperability. When considering your options, contact your Avaya representative to review some case studies and to explore design specifications and configuration options that will optimize your current infrastructure. | 
