About Registrations; Finding A Vcs With Which To Register; Registrations On A Vcs Expressway - Cisco TelePresence Administrator's Manual

About registrations

For an endpoint to use the 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 by using the
following mechanisms:
a device authentication
n
a registration restriction policy
n
service or an external policy service to specify which aliases can and cannot register with the VCS
restrictions based on IP addresses and subnet ranges through the specification of subzone membership
n
rules and subzone registration policies
You can use these 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.
For specific information about how registrations are managed across peers in a cluster, see the
registrations across peers

Finding a VCS with which to register

Before an endpoint can register with a VCS, it must determine which VCS it can or should be registering with.
This setting is configured on the endpoint, and the process is different for

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 Cisco TelePresence 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
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the endpoint's position in relation to the firewall
n
whether there is a NAT in use
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whether the endpoint is using a public IP address
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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.
Cisco VCS Administrator Guide (X7.1)
process based on the username and password supplied by the endpoint
that uses either Allow Lists or Deny
section.
Registration control
Lists, the VCS's on-box directory
SIP and H.323.
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