Understanding Video Components
As we discussed in the Introduction to IP Telephony section,VoIP is very intolerant
to delay and dropped packets.The statement is even more true when we
discuss IP-based video-conferencing or video over IP. Just imagine if you were
watching a video conference that was not received in real-time, perhaps a sales
presentation or some type of training, and the information was received out of
sequence—you could be looking at a chart that you heard about five minutes
ago. IP-based video transmissions as well as IP telephony are very similar in
nature.Voice, or in this case, video data is encapsulated into IP packets and transported
to the end destinations. In the following sections we will discuss some of
the components needed to facilitate IP-based video conferencing, such as gateways,
gatekeepers, multi-point control units (MCU), video terminal adapters
(VTA), and endpoints.We will also briefly discuss the IP/TV product line and
the services it provides. As with the rest of the AVVID product offerings, it is
highly recommended you consult Cisco’s Web site for the most up-to-date information
on the products and solutions that we will discuss in this section.