Problems Facing the
Integration of Voice and Data
A major problem that has slowed integration deployment of the telephony and
data networks is that there currently isn’t a standardized dynamic routing protocol
able to publicize dial plans between multiple telephony devices the way Open
Shortest Path First (OSPF) and Enhanced Interior Gateway Routing Protocol
(EIGRP) can in Cisco routers. In other words, these protocols are not currently
designed to handle the transport of this information, meaning other protocols
must first arise more specifically designed for voice and data architectures.Within
the traditional telecommunications infrastructures, switches and routers are manually
updated (there is limited automation) to reflect the routes located within the
device.Though this has led to a very stable platform, it also lends itself to administration
nightmares, as well as supreme support issues.
With voice and video networks, each destination and forwarding device along
a path needs to have a dial plan. In the data and packet networks, this consists of
implementing static routes, with the destination prefixes or even the direct destination
added to the routing table. As you probably know, static routes offer minimal
overhead on the network equipment since they basically act as a conduit for
information, but there is usually massive support overhead for problems that arise.
These problems are most often associated with the configuration (or misconfiguration)
of routers.This can affect the entire network if even one of the routers
along the path is incorrect. Should this occur, calls will not be able to terminate
at the proper destination, if at all.
There is a strong push to implement a dynamic routing protocol for telephony
devices, such as Simple Gateway Control Protocol (SGCP), Media
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Gateway Control Protocol (MGCP), Session Initiation Protocol (SIP), and the
newest,Telephony Border Gateway Protocol (TBGP).
Until these protocols gain acceptance and standardization, you will find that
all dial plans on Cisco voice-enabled routers need to be implemented through
dial peers. Dial peers are those commands used to configure the ports on routers
with an associated phone number.This will help the router to determine what
path is needed to complete the call.
As with other parts of designing an AVVID network using Cisco CallManager, a
dial plan should be a main consideration during the initial phase of the network
design.You should make sure you have the correct dial plan that’s suitably
designed the first time to negate the need to change it once it’s fully implemented.
These changes can be very time- and resource-consuming and may
lead you into areas where you will not be able to receive any support.
This chapter should give you an understanding of what a dial plan is and why
it is so important to the creation and support of your network infrastructure. It
will also explain the procedures of dial plan design for voice and video networks.