Cisco Cisco Expressway Maintenance Manual
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 128kbps, any calls between the two subzones will still be limited to 128kbps.
a pipe of 128kbps, 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.
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.
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.
Links and Pipes
Configuring Links
Links connect local subzones with other subzones and zones. For a call to take place, the endpoints involved must
each reside in subzones or zones that have a link between them. The link does not need to be direct; the two
endpoints may be linked via one or more intermediary subzones.
each reside in subzones or zones that have a link between them. The link does not need to be direct; the two
endpoints may be linked via one or more intermediary subzones.
Links are used to calculate how a call is routed over the network and therefore which zones and subzones are
involved and how much bandwidth is available. If multiple routes are possible, your Expressway will perform the
bandwidth calculations using the one with the fewest links.
involved and how much bandwidth is available. If multiple routes are possible, your Expressway will perform the
bandwidth calculations using the one with the fewest links.
The Links page (Configuration > Bandwidth > Links) lists all existing links and allows you to create, edit and delete
links.
links.
The following information is displayed:
Field
Description
Name
The name of the link. Automatically created links have names based on the nodes that the link is
between.
between.
Node 1 and
Node 2
Node 2
The Traversal Subzone and the zone that the link is between.
The two subzones, or one subzone and one zone, that the link is between.
Pipe 1 and
Pipe 2
Pipe 2
for more information. Note that in order to apply a pipe, you must first have
page.
Calls
Shows the total number of calls currently traversing the link.
Bandwidth
used
used
Shows the total amount of bandwidth currently being consumed by all calls traversing the link.
You can configure up to 3000 links. Some links are created automatically when a subzone or zone is created.
Default Links
If a subzone has no links configured, then endpoints within the subzone are only able to call other endpoints within
the same subzone. For this reason, the Expressway comes shipped with a set of pre-configured links and will also
automatically create new links each time you create a new subzone.
the same subzone. For this reason, the Expressway comes shipped with a set of pre-configured links and will also
automatically create new links each time you create a new subzone.
Pre-configured links
The Expressway is shipped with the Default Subzone, Traversal Subzone and Default Zone already created, and with
default links pre-configured between them as follows: DefaultSZtoTraversalSZ, DefaultSZtoDefaultZ and
default links pre-configured between them as follows: DefaultSZtoTraversalSZ, DefaultSZtoDefaultZ and
214
Cisco Expressway Administrator Guide
Bandwidth Control