You can apply bandwidth limits to the Default Subzone, Traversal Subzone and all manually
configured subzones. The types of limitations you can apply vary depending on the type of subzone,
as follows:

Limitation

Description

Can be applied to

Total

Limits the total concurrent bandwidth being
used by all endpoints in the subzone at
any one time. In the case of the Traversal
Subzone, this is the maximum bandwidth
available for all concurrent traversal calls.

•

Default Subzone

•

Traversal Subzone

•

Manually configured subzones

Calls entirely
within...

Limits the bandwidth of any individual call
between two endpoints within the subzone.

•

Default Subzone

•

Manually configured subzones

Calls into or
out of...

Limits the bandwidth of any individual call
between an endpoint in the subzone, and an
endpoint in another subzone or zone.

•

Default Subzone

•

Manually configured subzones

Calls
handled by...

The maximum bandwidth available to any
individual traversal call.

•

Traversal Subzone

For all these settings, a bandwidth mode of:

•

NoBandwidth means that no bandwidth is allocated and therefore no calls can be made.

•

Limited means that limits are applied. You must also enter a value in the corresponding
bandwidth (kbps) field.

•

Unlimited means that no restrictions are applied to the amount of bandwidth being used.

Use subzone bandwidth limits if you want to configure the bandwidth available between one
specific subzone and all other subzones or zones.
Use pipes if you want to configure the bandwidth available between one specific subzone

and another specific subzone or zone.
If your bandwidth configuration is such that multiple types of bandwidth restrictions are placed on
a call (for example, if there are both subzone bandwidth limits and pipe limits), the lowest limit will
always apply to that call.

How different bandwidth limitations are managed

In situations where there are differing bandwidth limitations applied to the same link, the lower limit
will always be the one used when routing the call and taking bandwidth limitations into account.
For example, Subzone A may have a per call inter bandwidth of 128. This means that any calls
between Subzone A and any other subzone or zone will be limited to 128kbps. However, Subzone A
also has a link configured between it and Subzone B. This link uses a pipe with a limit of 512kbps.
In this situation, the lower limit of 128kbps will apply to calls between the two, regardless of the
larger capacity of the pipe.
In the reverse situation, where Subzone A has a per call inter bandwidth limit of 512kbps and a
link to Subzone B with a pipe of 128, any calls between the two subzones will still be limited to
128kbps.

Bandwidth consumption of traversal calls

A non-traversal call between two endpoints within the same subzone would consume from that
subzone the amount of bandwidth of that call. A traversal call between two endpoints within the
same subzone must, like all traversal calls, pass through the Traversal Subzone. This means
that such calls consume an amount of bandwidth from the originating subzone’s total concurrent
allocation that is equal to twice the bandwidth of the call – once for the call from the subzone to
the Traversal Subzone, and again for the call from the Traversal Subzone back to the originating
subzone.
In addition, as this call passes through the Traversal Subzone, it will consume an amount of
bandwidth from the Traversal Subzone equal to that of the call.

Applying bandwidth limitations to subzones