Cisco Cisco Customer Voice Portal 8.0(1) Design Guide
12-3
Cisco Unified Customer Voice Portal (CVP) 8.x Solution Reference Network Design (SRND)
OL-15989-06
Chapter 12 Media File Options
Bandwidth Calculation for Prompt Retrieval
should be used as indicated below whenever you want to use a Micro-App for prompting. If you
subsequently want to use the VXML Server, you will have to rewrite this variable by following the
instructions above.
subsequently want to use the VXML Server, you will have to rewrite this variable by following the
instructions above.
1.
When setting up the media_server ECC variable that specifies your Media server in the ICM script,
use the Formula Editor to set the media_server ECC variable to
concatenate("http://",Call.RoutingClient), where Call.RoutingClient is the built-in call variable
that ICM sets automatically for you. The routing client name in ICM is not necessarily the same as
the Unified CVP Server's hostname (and usually is not the same).
use the Formula Editor to set the media_server ECC variable to
concatenate("http://",Call.RoutingClient), where Call.RoutingClient is the built-in call variable
that ICM sets automatically for you. The routing client name in ICM is not necessarily the same as
the Unified CVP Server's hostname (and usually is not the same).
2.
You can then use the name of the routing client as a hostname in the VXML gateway. However, do
not use non-compliant characters such as an underscore as part of the hostname because the router
cannot translate the hostname to an IP address if it contains any non-complaint characters. Cisco
also recommends using the ip hostname strict command in the router to prevent the use of invalid
characters in the hostname. This will ensure that the hostname is acceptable to Unified CVP.
not use non-compliant characters such as an underscore as part of the hostname because the router
cannot translate the hostname to an IP address if it contains any non-complaint characters. Cisco
also recommends using the ip hostname strict command in the router to prevent the use of invalid
characters in the hostname. This will ensure that the hostname is acceptable to Unified CVP.
3.
Configure the routing client hostname for every Unified CVP Server Routing Client.
Bandwidth Calculation for Prompt Retrieval
When prompts are stored on an HTTP media server, the refresh period for the prompts is defined on that
server. The bandwidth consumed by prompts consists of the initial loading of the prompts at each
gateway and of the periodic updates at the expiration of the refresh interval.
server. The bandwidth consumed by prompts consists of the initial loading of the prompts at each
gateway and of the periodic updates at the expiration of the refresh interval.
As an example of determining the bandwidth consumed by prompts, assume that a deployment has
50 prompts with an average size of 50 kB (50,000 bytes) each. Also assume that the refresh period for
the prompts is defined as 15 minutes (900 seconds) on the HTTP media server. The WAN bandwidth
required for prompts in this deployment can be calculated as follows:
50 prompts with an average size of 50 kB (50,000 bytes) each. Also assume that the refresh period for
the prompts is defined as 15 minutes (900 seconds) on the HTTP media server. The WAN bandwidth
required for prompts in this deployment can be calculated as follows:
(50 prompts)
∗ (50,000 bytes/prompt) ∗ (8 bits/byte) = 20,000,000 bits
(20,000,000 bits) / (900 seconds) = 22.2 kbps per branch
Configuring Caching and Streaming in Cisco IOS
The Cisco IOS VoiceXML Browser uses an HTTP client, which is a part of Cisco IOS. The client fetches
VoiceXML documents, audio files, and other file resources. There are two key properties associated
with playing audio prompts: caching and streaming. These two properties are closely related to each
other, and they can affect system performance greatly when the router is under load.
VoiceXML documents, audio files, and other file resources. There are two key properties associated
with playing audio prompts: caching and streaming. These two properties are closely related to each
other, and they can affect system performance greatly when the router is under load.
Streaming and Non-Streaming
In non-streaming mode, the entire audio file must be downloaded from the HTTP server onto the router
before the Media Player can start playing the prompt. This implies delay for the caller. If the audio file
is relatively small, the caller should not notice any delay because downloading a small file should take
only a few milliseconds. The delay of loading larger files can be overcome by using either caching or
streaming mode.
before the Media Player can start playing the prompt. This implies delay for the caller. If the audio file
is relatively small, the caller should not notice any delay because downloading a small file should take
only a few milliseconds. The delay of loading larger files can be overcome by using either caching or
streaming mode.
In streaming mode, the Media Player "streams" the audio in "media chunks" from the HTTP server to
the caller. As soon as the first chunk is fetched from the server, the Media Player can start playing. The
advantage of streaming mode is that there is no noticeable delay to the caller, irrespective of the size of
the audio prompt. The disadvantage of streaming mode is that, because of all of the back-and-forth
the caller. As soon as the first chunk is fetched from the server, the Media Player can start playing. The
advantage of streaming mode is that there is no noticeable delay to the caller, irrespective of the size of
the audio prompt. The disadvantage of streaming mode is that, because of all of the back-and-forth