Cisco Cisco TelePresence Video Communication Server Expressway
Appendix 6 – Configuring endpoints to work with a Cisco VCS cluster
Option 2 – DNS Round-Robin (2
nd
choice)
To use this option, there must be a DNS A-record available for the DNS name of the Cisco VCS
cluster that supplies a round-robin list of IP addresses.
cluster that supplies a round-robin list of IP addresses.
On each SIP endpoint configure the SIP Settings as:
Server discovery = Manual
Server Address = DNS name of the Cisco VCS cluster
If the endpoint does not support DNS SRV, on startup the endpoint will perform a DNS A-record
lookup. The DNS server will have been configured to support round-robin DNS, with each of the
cluster peer members defined in the round-robin list.
lookup. The DNS server will have been configured to support round-robin DNS, with each of the
cluster peer members defined in the round-robin list.
The endpoint will take the address given by the DNS lookup and will then try and register with the
relevant cluster peer. If that is not available, then the endpoint will perform another DNS lookup and
will try to connect to the new Cisco VCS peer that it is given. (The DNS server will have supplied the
next cluster peer’s IP address.)
relevant cluster peer. If that is not available, then the endpoint will perform another DNS lookup and
will try to connect to the new Cisco VCS peer that it is given. (The DNS server will have supplied the
next cluster peer’s IP address.)
This will be repeated until the endpoint can register with a Cisco VCS.
The endpoint will continue to use the first Cisco VCS that it registered to for re-registrations and for
calls. If it ever loses connection to its Cisco VCS it will perform another DNS lookup to find a new
Cisco VCS to register to (the DNS server providing a Cisco VCS in the round-robin sequence).
calls. If it ever loses connection to its Cisco VCS it will perform another DNS lookup to find a new
Cisco VCS to register to (the DNS server providing a Cisco VCS in the round-robin sequence).
DNS cache timeout should be set to a fairly short time (e.g. 1 minute or less) so that if a Cisco VCS is
not accessible the endpoint is quickly pointed at a different Cisco VCS.
not accessible the endpoint is quickly pointed at a different Cisco VCS.
Option 3 – Static IP (least preferred)
Use this option if the Cisco VCS cluster does not have a DNS name.
On each SIP endpoint configure the SIP Settings as:
Server discovery = Manual
Server Address = IP address of a Cisco VCS peer
On startup the endpoint will try and register with the Cisco VCS at the specified IP address. If that is
not available, then the endpoint will continue trying at regular intervals.
not available, then the endpoint will continue trying at regular intervals.
This will be repeated until the endpoint can register with the Cisco VCS.
The endpoint will continue to use the first Cisco VCS that it registered to for re-registrations and for
calls. If it ever loses connection then it will keep on trying to register to that Cisco VCS until it is
accessible again.
calls. If it ever loses connection then it will keep on trying to register to that Cisco VCS until it is
accessible again.
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