An H.323 endpoint attempts to register with a Cisco VCS by using an alias that has previously been registered
from another IP address.
Which of the following will occur if the Cisco VCS is configured with the default settings?

A.
The VCS will deny the new registration and maintain the old registration.

B.
The VCS will deny the new registration and remove the old registration.

C.
The VCS will replace the old registration with the new registration.

D.
The VCS will allow the new registration while maintaining the old registration.

Explanation:
By default, the Cisco TelePresence Video Communication Server (VCS) will deny the new registration and
maintain the old registration. When an H.323 endpoint registers with Cisco VCS, the endpoint sends one or
more of the following aliases to the VCS:
One or more H.323 IDs
One or more E.164 aliases
One or more Uniform Resource Identifiers (URIs)
If an endpoint attempts to register an alias that has previously been registered from another IP address, the
VCS will reject the registration by default. If you want to restore Cisco VCS to use the default mode for
registration conflicts, navigate to Configuration > Protocols > H.323 and set Registration conflict mode to
Reject.
The VCS will not replace the old registration with the new registration. However, you can configure Cisco VCS
to do so by navigating to Configuration > Protocols > H.323 and setting the Registration conflict mode option to
Overwrite. Overwrite mode is useful for networks in which endpoints change IP addresses frequently.You cannot configure Cisco VCS to deny a new registration and remove the old registration when a registration
conflict occurs. In addition, you cannot configure the VCS to allow multiple H.323 endpoints to register the
same alias. However, this functionality is possible with Session Initiation Protocol (SIP). A SIP endpoint can
register an alias that is already in use. When a call is placed to the alias, all endpoints that are registered with
that alias will ring simultaneously.
By default, H.323 endpoints can register with Cisco VCS either automatically or manually. If the H.323 endpoint
is set to automatic registration, the endpoint will send out a Gateway Discovery Request and eligible VCSs will
respond. If the H.323 endpoint is set to manual registration, the H.323 endpoint will be configured with the IPv4
address of the Cisco VCS and will be configured with an IPv4 address, subnet mask, and default gateway that
will allow the endpoint to communicate with the Cisco VCS.

Cisco: Cisco TelePresence Video Communication Server, Administrator Guide, Software version: X8.1:
Registering aliases (PDF)
Cisco: Cisco TelePresence Video Communication Server, Administrator Guide, Software version: X8.1: About
H.323 (PDF)
Cisco: Cisco TelePresence Video Communication Server, Administrator Guide, Software version: X8.1:
Configuring H.323 (PDF)