122
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
Subzones
All endpoints registered with the VCS are part
of its Local Zone.
The Local Zone is made up of two or more
subzones. The first two subzones are
automatically created for you, and can not
be deleted. These are the
Default Subzone
and the
Traversal Subzone
. You can create
and configure further subzones manually
on the basis of endpoints’ IP addresses:
when an endpoint registers with the VCS its
IP address is checked and it is assigned to
the appropriate subzone. See the sections
Creating a subzone
and
Configuring a subzon
e
for details on how to specify the range of IP
addresses for a subzone by using subnets.
If an endpoint’s IP address matches
more than one subzone, it will be
allocated to the subzone with the
narrowest subnet range.
The main purpose of all three types of
subzones is to enable you to control the
bandwidth used by various parts of your
network.
When an endpoint registers with the VCS,
its IP address is checked and it is assigned
to the appropriate subzone. If no subzones
have been created, or the endpoint’s IP
address does not match any of the configured
subzones, it will be assigned to the Default
Subzone.
The use of a Default Subzone on its own
(i.e. without any other manually configured
subzones) is suitable only if you have
uniform bandwidth available between all your
endpoints. However, it is possible for a Local
Zone to contain two or more different networks
with different bandwidth limitations. In this
situation, you should configure separate
subzones for each different part of the
network.
The VCS is shipped with the Default Subzone
and Traversal Subzone (and
Default Zone
)
already created, and with links between the
three. You may delete or amend these default
links if you need to model restrictions of your
network.
If any of these links have been deleted, they
may be automatically restored by using:
xCommand DefaultLinksAd
•
d
To restore these links from the web interface,
you must recreate them manually. See
Creating links
for instructions on how to do
this.
The Traversal Subzone is a conceptual subzone. No endpoints can be registered to the Traversal
Subzone; its sole purpose is to allow for the control of bandwidth used by
traversal calls
.
All traversal calls are deemed to pass through the Traversal Subzone, so by applying bandwidth
limitations to the Traversal Subzone you can control how much processing of media the VCS will
perform at any one time. These limitations can be applied on a total concurrent usage basis, and
on a per-call basis.
Traversal calls
A traversal call is any call passing through the VCS that includes both the signaling (information
about the call) and media (voice and video). The only other type of call is a non-traversal call,
where the signaling passes through the VCS but the media goes directly between the endpoints (or
between one endpoint and another VCS in the call route, or between two VCSs in the call route).
The following types of calls require the VCS to take the media. They are classified as traversal calls
and will always pass through the Traversal Subzone:
firewall traversal calls, where the local VCS is either the traversal client or traversal server
•
calls that are gatewayed (interworked) between H.323 and SIP on the local VCS
•
calls that are gatewayed (interworked) between IPv4 and IPv6 on the local VCS
•
for VCSs with Dual Network Interfaces enabled, calls that are inbound from one LAN port and
•
outbound on the other
a SIP to SIP call when one of the participants is behind a NAT.
•
All such calls will require a traversal call licence each time they pass through the Traversal
Subzone.
A call is “traversal” or “non-traversal” from the point of view of the VCS through which it is
being routed at the time. A call between two endpoints may pass through a series of VCSs.
Some of these systems may just take the signaling, in which case the call will be a
non-traversal call for that VCS. Other systems in the route may need to take the media as well, and
so the call will count as a traversal call on that particular VCS.
Bandwidth consumption of traversal calls
Traversal calls between two endpoints within a single subzone on the VCS must, like all traversal
calls, pass through the VCS’s Traversal Subzone. This means that such calls will 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, since this call passes through the Traversal Subzone, it will consume an amount of
bandwidth from the Traversal Subzone equal to that of the call.
About subzones and bandwidth
control
About the Traversal Subzone
About the Default Subzone
Default links between subzones
