Avaya Application Solutions Deployment Manual page 268

Reliability and Recovery
Case Study III (99.98% full system availability solution)
Case Study III demonstrates the impact of WAN link redundancy between all the sites. It is
assumed that each link has sufficient bandwidth to handle the full traffic in the event of a WAN
link failure.
The full system availability can improve to the range of 99.95% to 99.99% by implementing the
following redundancy in the configuration:
N+1 IP resources in each site. This applies to the number of C-LAN circuit packs and
media processor circuit packs in Atlanta and Boston. In Cleveland, each G700 media
gateway contains a resident VoIP resource, and each media gateway has the capacity of
housing an extra VoIP Media Module.
Redundant WAN links are present and properly configured to converge rapidly in case of
an outage.
Signaling and media traffic may take different routes across the network.
IP phones have at least three valid gatekeeper addresses that do not depend on the same
WAN link.
268 Avaya Application Solutions IP Telephony Deployment Guide