TANDBERG D14049.01 User Manual

Page of 187
D 14049.01
07.2007
58
D 14049.01
07.2007
58
The purpose of an Alternate is to provide extra 
reliability. 
Each VCS can be part of a pool of up to 6 
Alternate VCSs that act as backups to each 
other in case one becomes unavailable (for 
example, due to a network or power outage).
All the Alternates in a pool are configured 
similarly and share responsibility for their 
endpoint community.  When an endpoint 
registers with the VCS, it is given the 
IP addresses of all the VCS’s Alternates. If 
the endpoint loses contact with the initial 
VCS, it will seek to register with one of the 
Alternates. This may result in your endpoint 
community’s registrations being spread over 
all the Alternates.
When the VCS receives a Location Request, 
if it cannot respond from its own registration 
database, it will query all of its Alternates 
before responding. This allows the pool 
of endpoints to be treated as if they were 
registered with a single VCS. 
About Alternates
Each VCS can be configured with the IP 
addresses of up to five other VCSs that will 
act as Alternates should the current VCS 
become unavailable. 
To configure Alternate VCSs:
VCS Configuration > Alternates
.   
You will be taken to the 
Alternates
 page.
Alternate 1 to Alternate 5 IP address
To configure another VCS as an Alternate, enter its IP address.  
Up to 5 Alternates may be configured.
Save
Click 
Save 
to save your 
changes.
Configuring Alternates
Alternates are not used to increase 
the capacity of your network; they are 
to provide redundancy.  To increase 
the capacity of your network, add one or more 
additional VCSs and neighbor them together.
Alternates are periodically interrogated 
to ensure that they are still 
functioning. In order to prevent delays 
during call setup, any non-functioning 
Alternates will not receive Location Requests.
!
You must configure all Alternates in a 
pool identically for all registration and 
call features such as authentication, 
bandwidth control and policy. If you do not do 
this, endpoint behavior will vary unpredictably 
depending on which Alternate it is currently 
registered with. Alternates should also be 
deployed on the same LAN as each other so 
that they may be configured with the same 
routing information such as local domain 
names and local domain subnet masks.
When configuring your VCS with the 
details of the system it will be using as 
a traversal server, you are given the 
opportunity to include details of any Alternates 
of that traversal server. Adding this 
information to your VCS will ensure that, if the 
original traversal server becomes unavailable, 
your VCS can use one of its Alternates 
instead.
TANDBERG 
VIDEO COMMUNICATION SERVER 
ADMINISTRATOR GUIDE
Managing Zones, Neighbors and Alternates