53
D14049.07
March 2010
Grey Headline
(continued)
TANDBERG
VIDEO COMMUNICATION SERVER
ADMINISTRATOR GUIDE
Introduction
Overview and
status
System
configuration
VCS
configuration
Zones and
neighbors
Clustering and
peers
Call
processing
Bandwidth
control
Firewall
traversal
Appendices
Applications
Maintenance
Registration control
Endpoint registration
For an endpoint to use the TANDBERG VCS as its H.323
gatekeeper or SIP registrar, the endpoint must first register with
the VCS. The VCS can be configured to control which devices
are allowed to register with it. Two separate mechanisms are
provided:
•
a
device authentication process
based on the username and
password supplied by the endpoint
•
a simple Registration Restriction Policy that uses
Allow Lists
or Deny Lists
to specify which aliases can and cannot register
with the VCS, and the ability to control registrations based on
IP addresses and subnet ranges through the specification of
subzone membership rules and
subzone registration policies
.
It is possible to use both mechanisms together. For example,
you can use authentication to verify an endpoint’s identity from a
corporate directory, and registration restriction to control which
of those authenticated endpoints may register with a particular
VCS.
This section gives an overview of how endpoints and other
devices register with the VCS, and then describes the two
mechanisms by which registrations can be restricted.
For specific information about how registrations are
managed across peers in a cluster, see the
Sharing
registrations across peers
section.
Registration overview
MCU, gateway and Content Server registration
H.323 systems such as gateways, MCUs and Content Servers
can also register with a VCS. They are known as locally
registered services. These systems are configured with their own
prefix, which they provide to the VCS when registering. The VCS
will then know to route all calls that begin with that prefix to the
gateway, MCU or Content Server as appropriate. These prefixes
can also be used to control registrations.
SIP devices cannot register prefixes. If your dial plan dictates
that a SIP device should be reached via a particular prefix,
then you should add the device as a neighbor zone with an
associated search rule using a pattern match equal to the prefix
to be used.
The TANDBERG MPS and TANDBERG Content Server
(TCS) both support Expressway. They can therefore
register directly with a VCS Expressway for firewall
traversal.
Registrations on a VCS Expressway
If a traversal-enabled endpoint registers directly with a VCS
Expressway, the VCS Expressway will provide the same services
to that endpoint as a VCS Control, with the addition of firewall
traversal. Traversal-enabled endpoints include all TANDBERG
Expressway™ endpoints and third party endpoints which support
the ITU H.460.18 and H.460.19 standards.
Endpoints that are not traversal-enabled can still register with
a VCS Expressway, but they may not be able to make or receive
calls through the firewall successfully. This will depend on a
number of factors:
•
whether the endpoint is using SIP or H.323
•
the endpoint’s position in relation to the firewall
•
whether there is a NAT in use
•
whether the endpoint is using a public IP address
For example, if an endpoint is behind a NAT or firewall, it may not
be able to receive incoming calls and may not be able to receive
media for calls it has initiated. SIP endpoints can also work
behind a NAT but can only receive video if they send it as well.
To ensure firewall traversal will work successfully for H.323
endpoints behind a NAT, the endpoint must be traversal-enabled.
