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D 14049.01
07.2007
59
D 14049.01
07.2007
59
Introduction
Getting
Started
System
Overview
System
Configuration
H.323 & SIP
Configuration
Registration
Control
Zones and
Neighbors
Call
Processing
Firewall
Traversal
Bandwidth
Control
Maintenance
Appendices
Zones and
Neighbors
About Dial Plans
As you start deploying more than one VCS, it is useful to
neighbor the systems together so that they can query each
other about their registered endpoints. Before you start, you
should consider how you will structure your dial plan. This will
determine the aliases assigned to the endpoints, and the way in
which the VCSs are neighbored together. The solution you chose
will depend on the complexity of your system. Some possible
options are described below.
Flat Dial Plan
The simplest approach is to assign each endpoint a unique
alias and divide the endpoint registrations between the VCSs.
Each VCS is then configured with all the other VCS as neighbor
zones. When one VCS receives a call for an endpoint which is
not registered with it, it will send out a Location Request to all
the other neighbor VCSs.
Whilst conceptually simple, this sort of flat dial plan does not
scale very well. Adding or moving a VCS requires changing the
configuration of every VCS, and one call attempt can result in
a large number of location requests. This option is therefore
most suitable for a deployment with just one or two VCSs and its
Alternates.
Structured Dial Plan
An alternative deployment would use a structured dial plan
whereby endpoints are assigned an alias based on the system
they are registering with.
If you are using E.164 aliases, each VCS would be assigned
an area code. When the VCSs are neighbored together, each
neighbor zone is configured with its corresponding area code
as a prefix (i.e. a Match Mode of Pattern and a Type of Prefix).
That neighbor will now only be queried for calls to numbers which
begin with its prefix.
In a URI based dial plan, similar behavior may be obtained by
configuring neighbors with a suffix to match the desired domain
name.
It may be desirable to have endpoints register with just the
subscriber number -- the last part of the E.164 number. In
that case, the VCS could be configured to strip prefixes before
sending the query to that zone.
A structured dial plan will minimize the number of queries
issued when a call is attempted. However, it still requires a fully
connected mesh of all VCSs in your deployment. A hierarchical
dial plan can simplify this.
Hierarchical Dial Plan
In this type of structure one VCS is nominated as the Directory
for the deployment, and all other VCSs are neighbored with
it alone. Each VCS is configured with the Directory VCS as a
neighbor zone with a Match Mode of Always, and the Directory
VCS is configured with each VCS as a neighbor zone with a
Match Mode of Pattern and its prefix as the Pattern String.
There is no need to neighbor the VCSs with each other. Adding
a new VCS now only requires changing configuration on that
system and the Directory VCS.
However, failure of the Directory VCS in this situation could
cause significant disruption to communications. Consideration
should be given to the use of Alternates for increased resilience.
Setting up a Dial Plan
TANDBERG VIDEO COMMUNICATION SERVER
ADMINISTRATOR GUIDE
Managing Zones, Neighbors and Alternates