Cisco Cisco Customer Voice Portal 8.0(1) Design Guide

Unified CVP can support both G.711 and G.729. However, both call legs and all IVR on a given call 
must use the same voice codec. If you are using ASR/TTS for speech recognition, then G.711 must be 
used because ASR/TTS servers support only G.711. For the most current bandwidth information on 
voice RTP streams, refer to the latest version of the Cisco Unified Communications SRND Based on 
Cisco Unified Communications Manager, available at 

Call admission control is the mechanism for determining if there is enough bandwidth available on the 
network to carry an RTP stream. Unified CM can use its own locations mechanism or RSVP to track 
bandwidth between the ingress gateway and destination IP phone locations.

For more information about call admission control, see the chapter on 

.

RSVP. Cisco Unified CM 5.0 introduced support for Resource Reservation Protocol (RSVP) between 
endpoints within a cluster and Unified CM Release 8.0 introduces RSVP over the SIP trunk. RSVP is a 
protocol used for call admission control, and it is used by the routers in the network to reserve bandwidth 
for calls. RSVP is not qualified for call control signaling via the Unified CVP Call Server in SIP or H.323 
in the 8.0(1) release. The recommended solution for Call Admission Control is to employ Locations 
configuration on Unified CVP and in Unified CM.

For more information on RSVP, refer to the latest version of the Cisco Unified Communications SRND 
Based on Cisco Unified Communications Manager, available at 

When you are using the Unified CVP Branch Office call flow model deployment you need to control the 
number of calls that go over the WAN link to branch offices, based on the available bandwidth of the 
WAN link. Decisions for admitting calls are based on the Call Admission Control (CAC) computations 
which must be correct and representative of the bandwidth being used by an individual call. These 
computations must work whether the calls are IP call between two phones within CCM, calls over 
SIP/H.323 trunks, or calls originated from TDM-IP GW. 

Additionally, for queue-at-the-edge functionality, the call originating from a specific branch office 
should be deterministically routed to a local VXML Gateway based on priority. That is, always choose 
a local branch agent if possible.

The following diagram illustrates a typical branch office deployment.