52
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
Interworking
The VCS is able to act as a gateway between SIP and H.323, translating calls from one protocol to
the other. This is known as “interworking”.
By default, the VCS acts as a SIP-H.323 and H.323-SIP gateway but only if at least one of the
endpoints that are involved in the call is locally registered. You can change this setting so that
the VCS will act as a SIP-H.323 gateway regardless of whether the endpoints involved are locally
registered. You also have the option to disable interworking completely.
The VCS uses the protocol of the incoming call when searching a zone for a given alias. If
the search is unsuccessful the VCS may then search the same zone again using the
alternative protocol, depending on where the search came from and the
Interworking mode
(
VCS configuration > Protocols > Interworking
).
If the request has come from a neighboring system and
Interworking mode
is set to
RegisteredOnly
, the VCS will search the Local Zone using both protocols, and all other zones using
the native protocol only (because it will interwork the call only if one of the endpoints is locally
registered). If
Interworking mode
is set to
On
, or the request has come from a locally registered
endpoint, the VCS will search the Local Zone and all external zones using both protocols.
Calls for which the VCS acts as a SIP to H.323 gateway are traversal calls. They will
therefore require a traversal call license.
Overview
Configuring interworking
The
Interworking
page is used to configure whether or not the VCS acts as a gateway between SIP
and H.323 calls.
To go to the
Interworking
page:
•
VCS configuration > Protocols > Interworking
To configure interworking using the CLI:
•
xConfiguration Interworking Mode
H.323 <-> SIP interworking mode
The options for this setting are:
Off
: the VCS will not act as a SIP-H.323 gateway.
RegisteredOnly
: the VCS will act as a SIP-H.323 gateway but only if at least one of the endpoints is
locally registered.
On
: the VCS will act as a SIP-H.323 gateway regardless of whether the endpoints are locally
registered.
!
You are recommended to leave this setting as
RegisteredOnly
(where calls are
interworked only if at least one of the endpoints is locally registered). Unless your network
is correctly configured, setting it to
On
(where all calls can be interworked) may result in
unnecessary interworking, for example where a call between two H.323 endpoints is made over
SIP, or vice versa.
Enabling SIP endpoints to dial H.323 numbers
SIP endpoints can only make calls in the form of URIs - e.g.
name@domain
. If the caller does not
specify a domain when placing the call, the SIP endpoint will automatically append its own domain
to the number that is dialed. So if you dial
123
from a SIP endpoint, the search will be placed for
123@domain
. If the H.323 endpoint being dialed is just registered as
123
, then the VCS won't be
able to locate the alias
123@domain
and the call will fail.
The solutions are to either:
1. Ensure all your endpoints, both H.323 and SIP, register with an alias in the form
name@domain
.
2. Create a pre-search transform on the VCS that strips the
@domain
portion of the alias for those
URIs that are in the form of
number@domain
.
Refer to the
Pre-search transforms
section for information on how to configure pre-search
transforms, and to the
Stripping @domain for dialing to H.323 numbers
section for an example
of how to do this.
