TANDBERG D14049.01 About Dial Plans, Flat Dial Plan, Setting up a Dial Plan, Structured Dial Plan

Managing Zones, Neighbors and Alternates

TANDBERG VIDEO COMMUNICATION SERVER ADMINISTRATOR GUIDE

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.

Introduction	Getting	System	System
	Started	Overview	Configuration

D 14049.01

07.2007

Setting up a Dial Plan

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.

H.323 & SIP	Registration	Zones and	Call
Configuration	Control	Neighbors	Processing

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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.

Firewall	Bandwidth	Maintenance	Appendices
Traversal	Control