Cisco Cisco Customer Voice Portal 8.0(1) Design Guide
9-5
Cisco Unified Customer Voice Portal (CVP) 8.x Solution Reference Network Design (SRND)
OL-15989-06
Chapter 9 Network Infrastructure Considerations
Bandwidth Sizing
Data Traffic
Data traffic includes VoiceXML documents and prerecorded media files returned as a result of HTTP
requests executed by the VoiceXML gateway. Specifically:
requests executed by the VoiceXML gateway. Specifically:
•
The VoiceXML gateway requests media files in an HTTP request to a media file server. The media
server response returns the media file in the body of the HTTP message. The VoiceXML gateway
then converts the media files to RTP packets and plays them to the caller. The connection in this case
can be over a WAN or LAN.
server response returns the media file in the body of the HTTP message. The VoiceXML gateway
then converts the media files to RTP packets and plays them to the caller. The connection in this case
can be over a WAN or LAN.
•
The VoiceXML gateway requests VoiceXML documents from either the Unified CVP
VXML Server or the Unified CVP IVR Service. The connection in this case can be over a WAN or
LAN.
VXML Server or the Unified CVP IVR Service. The connection in this case can be over a WAN or
LAN.
This chapter focuses primarily on the types of data flows and bandwidth used between a remote ingress
gateway and the components with which it interfaces:
gateway and the components with which it interfaces:
•
Unified CVP VXML Server
•
Unified CVP Call Server IVR Service
•
Unified CVP Call Server SIP or H.323 Service
•
IP phones
•
Media servers
•
Egress gateways
•
ASR or TTS servers
Guidelines and examples are presented to help estimate required bandwidth and, where applicable,
provision QoS for these network segments.
provision QoS for these network segments.
Bandwidth Sizing
As discussed above, most of the bandwidth requirements in a Unified CVP solution occur in a
Distributed Unified CVP topology, due primarily to the fact that the ingress and/or VoiceXML gateway
is separated from the servers that provide it with media files, VoiceXML documents, and call control
signaling. For purposes of the following discussion, assume all calls to a branch begin with one minute
of IVR treatment followed by a single transfer to an agent that also lasts one minute. Each branch has
20 agents, and each agent handles 30 calls per hour for a total of 600 calls per hour per branch. The call
average rate is therefore 0.166 calls per second (cps) per branch.
Distributed Unified CVP topology, due primarily to the fact that the ingress and/or VoiceXML gateway
is separated from the servers that provide it with media files, VoiceXML documents, and call control
signaling. For purposes of the following discussion, assume all calls to a branch begin with one minute
of IVR treatment followed by a single transfer to an agent that also lasts one minute. Each branch has
20 agents, and each agent handles 30 calls per hour for a total of 600 calls per hour per branch. The call
average rate is therefore 0.166 calls per second (cps) per branch.
Note that even a slight change in these variables might have a large impact on sizing. It is important to
remember that .166 calls per second is an average for the entire hour. Typically, calls do not come in
uniformly across an entire hour, and there are usually peaks and valleys within the busy hour. Try to find
the busiest traffic period, and calculate the call arrival rate based on the worst-case scenario.
remember that .166 calls per second is an average for the entire hour. Typically, calls do not come in
uniformly across an entire hour, and there are usually peaks and valleys within the busy hour. Try to find
the busiest traffic period, and calculate the call arrival rate based on the worst-case scenario.
VoiceXML Documents
VoiceXML (VXML) documents are generated based on voice application scripts written using either
Unified ICM scripts or Cisco Unified Call Studio, or both. A VoiceXML document is generated for every
prompt that is played to the caller. The VoiceXML documents vary in size, depending on the type of
prompt being used; menu prompts with many selections are much larger than a simple prompt that
simply plays an announcement.
Unified ICM scripts or Cisco Unified Call Studio, or both. A VoiceXML document is generated for every
prompt that is played to the caller. The VoiceXML documents vary in size, depending on the type of
prompt being used; menu prompts with many selections are much larger than a simple prompt that
simply plays an announcement.