Guidelines for the Design and
Implementation of Dial Plans
.. As with any project, its complexity will depend on the number of
variables factored in. Dial plan complexity can vary, based on any
number of configuration choices, such as the total amount of paths a call
can be sent through.
.. When configuring single-site campuses, you will often implement a
simple dial plan that can provide intraoffice calling (with four or five
digits depending on the site) and connections to the PSTN (usually by
dialing a 9). Long distance would also be handled by the PSTN with the
dialing party using a 9, then a 1, and the area code before dialing the
seven-digit number.
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AVVID Dial Plans • Chapter 9 329
.. When you go to implement AVVID, you should work under the
assumption that the less complex it is, the better. Find out what is used
on a normal (daily) basis, and what features are seldom used.With these
answers, you can create a plan that meets the needs of the client.
.. Based on the assumption that this will be a Cisco IOS-based H.323
gateway, you would then point the router POTS dial peer to the PSTN
port (or ports) and use a destination pattern of “9” to match the leading
digit that will come from the Cisco CallManager.The match on the “9”
will make the dial peer remove the 9, so the rest of the number is
passed.
.. When creating a dial plan for a multisite WAN, you must have sufficient
resources to make it function properly. If you don’t have the proper link
bandwidth, the call will always route over the PSTN, negating the
benefits that multisite WAN connections are supposed to give you.