Introduction to Video
Traditional old world video transmissions typically consist of one to several ISDN
basic rate interface (BRI) lines connecting proprietary video-conferencing endstations.
These ISDN lines typically operate in a point-to-point infrastructure utilizing
the H.320 specification. Usually the bandwidth used is anywhere from 128
Kbps to 384 Kbps, and is kept completely separate from the existing data and voice
infrastructures, which results in a large under-utilization of available resources.
Although some advanced PBX systems can terminate the BRI lines for the video
conferencing systems, the BRI lines and voice lines are kept completely separate
from one another. As the technology has improved over the last several years, this
type of system has gained a great deal of popularity and it is not uncommon to
find some form of this system in most mid- to large-sized organizations.
New world IP-based video conferencing systems allow you to utilize your
existing data networking infrastructure as opposed to working with a separate
infrastructure, resulting in much better utilization of your network resources.
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IP-based video conferencing, on the other hand, utilizes the H.323 specification
(discussed earlier in this chapter), allowing you to utilize video conferencing over
a variety of mediums including shared and switched media such as Ethernet,
leased lines, and nonbroadcast multiaccess networks such as Frame Relay and
Asynchronous Transfer Mode (ATM).
As part of the AVVID line of solutions, Cisco offers several solutions to enable
video-conferencing to meet the varying needs of organizations of a range of sizes.
In the following section we will discuss IP-based video conferencing in greater
detail, as well as some of the components used for IP-based video conferencing.