128
D14049.05
February 2009
Grey Headline
(continued)
TANDBERG
VIDEO COMMUNICATIONS SERVER
ADMINISTRATOR GUIDE
Introduction
Getting started
Overview and
status
System
configuration
VCS
configuration
Zones and
neighbors
Call
processing
Bandwidth
control
Firewall
traversal
Appendices
Applications
Maintenance
Default bandwidth and downspeeding
If bandwidth control is in use, there may be situations when there is insufficient bandwidth
available to place a call at the requested rate. By default (and assuming that there is some
bandwidth still available) the VCS will still attempt to connect the call, but at a reduced bandwidth –
this is known as
downspeeding
.
Downspeeding can be configured so that it is applied in either or both of the following scenarios:
when the requested bandwidth for the call exceeds the lowest
•
per-call
limit for the subzone or
pipe(s)
when placing the call at the requested bandwidth would mean that the
•
total
bandwidth limits for
that subzone or pipe(s) would be exceeded.
You can turn off downspeeding, in which case if there is insufficient bandwidth to place the call
at the originally requested rate, the call will not be placed at all. This could be used if, when your
network is nearing capacity, you would rather a call failed to connect at all than was connected
at a lower than requested speed. In this situation users will get one of the following messages,
depending on the message that initiated the search:
Exceeds Call Capacity
•
Gatekeeper Resources Unavailable
•
About the default call bandwidth
To configure the default call bandwidth and downspeeding behavior using the web interface:
VCS configuration > Bandwidth > Configuration
•
.
You will be taken to the
Bandwidth Configuration
page.
To configure these settings using the CLI:
xConfiguration Bandwidth Defaul
•
t
xConfiguration Bandwidth Downspee
•
d
The options are:
Default call bandwidth (kbps)
Enter the bandwidth value to be used for calls for which no bandwidth value has been specified by
the system that initiated the call.
This value cannot be blank. The default value is 384 kbps.
Downspeed per call mode
Determines what will happen if the
per-call
bandwidth restrictions on a subzone or pipe mean that
there is insufficient bandwidth available to place a call at the requested rate.
On
: the call will be downspeeded.
Off
: the call will not be placed.
Downspeed total mode
Determines what will happen if the
total
bandwidth restrictions on a subzone or pipe mean that
there is insufficient bandwidth available to place a call at the requested rate.
On
: the call will be downspeeded.
Off
: the call will not be placed.
Usually, when a call is initiated the endpoint will include in the request the amount of bandwidth it
wishes to use. For those cases where the endpoint has not specified the bandwidth, you can set
the VCS to apply a default bandwidth value.
Configuring default call bandwidth and downspeeding
About downspeeding