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H.323
TANDBERG VIDEO COMMUNICATIONS SERVER ADMINISTRATOR GUIDE
H.323 Overview
H.323 Endpoint Registration
About H.323 on the VCS
The VCS supports the H.323 protocol: it is an H.323 gatekeeper, and will provide interworking between H.323 and SIP calls. In order to support H.323, the H.323 mode must be enabled.
Using the VCS as an H.323 Gatekeeper
As an H.323 gatekeeper, the VCS accepts registrations from H.323 endpoints and provides call control functions such as address translation and admission control.
Overview
H.323 endpoints in your network must register with the VCS in order to use it as their gatekeeper.
There are two ways an H.323 endpoint can locate a VCS with which to register: manually or automatically. The option is configured on the endpoint itself under the Gatekeeper Discovery setting (consult your endpoint manual for how to access this setting).
•If the mode is set to automatic, the endpoint will try to register with any VCS it can find. It does this by sending out a Gatekeeper Discovery Request, to which eligible VCSs will respond.
•If the mode is set to manual, you must specify the IP address of the VCS with which you wish your endpoint to register, and the endpoint will attempt to register with that VCS only.
Auto Discover
The VCS has an Auto Discover setting which determines whether it will respond to the Gatekeeper Discovery Requests sent out by endpoints.
To prevent H.323 endpoints being able to register automatically with the VCS, set Auto Discover to Off. This will mean that endpoints will be able to register with the VCS only if they have been configured with the VCS’s IP address.
Time to Live
H.323 endpoints must periodically
Configuring H.323 Ports
The VCS allows you to configure the listening port for H.323 registrations and call signaling, and the range of ports to be used by H.323 calls once they are established.
The default VCS configuration uses standard port numbers so you can use H.323 services out of the box without having to first set these up.
Registration Conflict Mode
An H.323 endpoint may attempt to register with the VCS using an alias that has already been registered on the VCS from another IP address. The reasons for this could include:
•two endpoints at different IP addresses are attempting to register using the same alias
•a single endpoint has previously registered using a particular alias. The IP address allocated to the endpoint then changes, and the endpoint is attempting to
alias.
You can determine how the VCS will behave in this situation by configuring the Registration Conflict Mode. The options are:
•Reject: denies the new registration.
•Overwrite: deletes the original registration and replaces it with the new registration.
Some older endpoints do not support the ability to
periodically
in any other situation where the system has not had a confirmation from the endpoint within the specified period, it will send an IRQ to the endpoint to verify that it is still functioning.
Call Time to Live
Once the endpoint is in a call, the VCS will periodically poll it to confirm whether it is still in the call. If the endpoint does not respond, the call will be disconnected.
The VCS allows you to configure the interval at which the endpoints are polled, known as the Call Time to Live.
The system will poll endpoints in a call regardless of whether the call type is traversal or
Introduction | Getting Started |
| Overview and |
| System | VCS | Zones and |
| Call |
| Bandwidth |
| Firewall |
| Maintenance |
| Appendices |
| Status |
| Configuration | Configuration | Neighbors |
| Processing |
| Control |
| Traversal |
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MAY 2008 |
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