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 Appe ndices
Zones and
Neighbors
About Dial Plans
As you start deploying mor e than one VCS, it is useful to
neighbor the systems together s o that they can query each
other about their registered e ndpoints. Before you star t, you
should consider how you will stru cture your dial plan. This will
determine the aliases assigne d to the endpoints, and the way in
which the VCSs are neighbored t ogether. The solution you chose
will depend on the complexit y of your system. Some possible
options are described below.
Flat Dial Plan
The simplest approach is to assig n each endpoint a unique
alias and divide the endpoint re gistrations between the VC Ss.
Each VCS is then configured wit h all the other VCS as neighbor
zones. When one VCS receives a call fo r an endpoint which is
not registered with it, it will send o ut a Location Request to all
the other neighbor VCSs.
Whilst conceptually simple, this s ort of flat dial plan does not
scale very well. Adding or movin g a VCS requires changing the
configuration of every VCS, a nd one call attempt can result i n
a large number of location requ ests. This option is therefore
most suitable for a deploymen t with just one or two VCSs and its
Alternates.
Structured Dial Plan
An alternative deployment w ould use a structured dial pla n
whereby endpoints are assign ed an alias based on the system
they are registering with.
If you are using E.164 aliases, each VCS woul d be assigned
an area code. When the VCSs are neig hbored together, each
neighbor zone is configured wi th its corresponding are a code
as a prefix (i.e. a Match Mode of Patte rn and a Type of Prefix).
That neighbor will now only be que ried for calls to numbers whic h
begin with its prefix.
In a URI based dial plan, similar behav ior may be obtained by
configuring neighbors wi th a suffix to match the desi red domain
name.
It may be desirable to have endpoin ts register with just the
subscriber number -- th e last part of the E.164 number. In
that case, the VCS could be confi gured to strip prefixes before
sending the query to that zon e.
A structured dial plan will minimi ze the number of queries
issued when a call is attempted. Ho wever, it still requires a fully
connected mesh of all VCSs in your de ployment. A hierarchical
dial plan can simplify this.
Hierarchical Dial Plan
In this type of structure on e VCS is nominated as the Director y
for the deployment, and all othe r VCSs are neighbored with
it alone. Each VCS is configured wi th the Directory VCS as a
neighbor zone with a Match Mod e of Always, and the Director y
VCS is configured with each VCS as a n eighbor zone with a
Match Mode of Pattern and its p refix as the Pattern Str ing.
There is no need to neighbor the VC Ss with each other. Adding
a new VCS now only requires changin g configuration on that
system and the Directory VCS .
However, failure of the Directory VC S in this situation could
cause significant disrupti on to communications. Consid eration
should be given to the use of Altern ates for increased resilience.
Setting up a Dial Plan
TANDBERG VIDEO COMMUNICATION SERVER
ADMINISTRATOR GUIDE
Managing Zones, Neighbors and Alternates