What Is a Dial Plan?
.. Configuring dial peers for use is essential when designing and
implementing Voice over IP on your network. Dial peers identify the
calling source and the destination points so as to define what attributes
are assigned to each call.
.. Configuring a dial peer for POTS can help you shape the deployment
of your dial peers.
.. By configuring VoIP dial peers, you can enable the router to make
outbound calls to other telephony devices located within the network.
.. Dial peers for inbound and outbound calls are used to receive and
complete calls.You must remember that the definition of inbound and
outbound is based on the perspective of the router.What this means is
that a call coming into the router is considered an inbound call and a
call originating from the router is considered an outbound call.
.. To associate a dialed string with a specific telephony device, you would
use the destination pattern.With it, the dialed string will compare itself
to the pattern and then will be routed to the voice port or the session
target (discussed later) voice network dial peer. If the call is an outbound
call, the destination pattern could also be used to filter the digits that
will be forwarded by the router to the telephony device or the PSTN.A
destination pattern must be configured for each and every POTS and
VoIP dial peer configured on the router.
.. The session target is the IP address of the router to which the call will
be directed once the dial peer is matched.
.. Route patterns (on-net) allow you to connect to multiple sites across a
WAN with connections like frame or dedicated circuits using available
network resources.
.. With Cisco CallManager, you are able to create route patterns that allow
you to route calls that differentiate between local calls and long distance
calls.
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In this chapter, we talked about how a dial plan is, in its most basic form, a
system interface for telephony devices that allows users and equipment to connect
to each other by using dialing strings.These dial strings can be mapped and
routed to a multitude of locations by the controlling system.AVVID implementation
uses routers like filters to match dial peers.When a call arrives on a POTS
port, the router will match the VoIP dial peer for the outbound call. A dial plan
allows you to design your network so it can accommodate data and voice/video
within the same infrastructure. A dial plan can be created in many different ways,
depending on the needs surrounding each individual deployment.
These plans can include redundant paths, for IP networks and the PSTN, so
there will be a path to completion for calls made.
By using Cisco CallManager, you are able to allow for greater growth and
functionality within your network because Cisco CallManager was designed to
be integrated with IOS gateways to allow for greater functionality while streamlining
the installation.
We also saw that within Cisco CallManager, you can create calling restrictions
on a per telephony device, or create closed dial plan groups as long as they fall
within the same Cisco CallManager.This ensures that users residing within the
same Cisco CallManager can be grouped together with the same calling restrictions
and dial plans for ease of administration.
We also talked about the implementation of H.323 gatekeepers.These gatekeepers
handle admission control so you are able to control the number of calls
allowed to and from specific areas.We saw how this would assist you in the management
of bandwidth and resources for your sites and overall infrastructure.The
gatekeeper can also assist with address resolution.The Cisco CallManager knows
what ranges of extensions are within its control and is able to route the calls to
the proper destination. If the extension is not local to the Cisco CallManager, it
will then go to the gatekeeper for the address of another Cisco CallManager that
can direct the call to its destination.
In the LAN, it is becoming more and more feasible to introduce video and
other multiservice technologies to better leverage the local area network and its
increasing speed.With the implementation of AVVID and the usage of H.323
gateways, video to the desktop is becoming more and more commonplace.
By using Cisco AVVID video gateways, internal users can communicate more
efficiently and seamlessly.