34.6 CISCO S ARCHITECTURE FOR VOICE, VIDEO, AND INTEGRATED DATA (AVVID)

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34.6 CISCO'S ARCHITECTURE FOR VOICE, VIDEO, AND INTEGRATED DATA (AVVID)

Cisco, the pioneer in communications technology, developed the Architecture for Voice, Video, and Integrated Data (AVVID) to provide voice/video/fax services over IP networks. Using AVVID, an enterprise can provide efficient customer service through Internet-enabled call centers as well as reduce its communication costs drastically using voice over IP, video over IP, and fax over IP. The block diagram of AVVID is shown in Figure 34.10.

Figure 34.10: Architecture for Voice, Video and Integrated Data (AVVID).

Cisco's Architecture for Voice, Video, and Integrated Data (AVVID) provides voice/data/fax/ video services over IP networks.

The various components of this architecture are described in the following:

IP phone: The IP phone is a standalone phone running the H.323 protocols. It can be connected to the switch using an Ethernet interface. A user can make calls to any PSTN phone or any other IP phone. Voice will be packetized and sent over the IP network.

Multimedia PC: The PC can also act as an IP phone. The PC will be running the H.323 protocol stack to provide audio and video services. This will also be connected to the switch using an Ethernet interface.

Fax machine: The fax machine will be connected to the gateway to facilitate fax over IP as discussed in the previous section.

PBX: The legacy PBX can be connected to make telephone calls from the PBX extensions. The PBX will be connected to the gateway through trunks. The existing connectivity between the PSTN and the PBX can continue.

Switch: The switch provides the necessary functionality to switch the calls. In conjunction with the call manager, it obtains the necessary information for routing a call and switches the call to the appropriate destination either on the PSTN or on the PBX.

Gateway: The gateway does the necessary protocol translation. Since the call processing functions and voice-coding formats are different in PSTN and IP networks, the necessary translations are done here. For example, the PCM-coded speech is converted into H.323 standards–based speech coding. Similarly, the protocol differences in fax messaging are handled by the gateway.

Call manager: The call manager is an IP-based PBX running on Windows 2000 Server. Through software, all call processing software is implemented. The call manager also contains the directory of users (equivalent to a telephone directory, but with IP addresses of the phones). Using dedicated hardware, it carries out the necessary voice coding per H.323 standards.

The call manager is an IP-based PBX that runs on Windows 2000 Server. The call manager carries out call processing and low bit rate coding of voice. It also keeps a directory of users.

The system shown in Figure 34.10 can be enhanced by integrating other products such as these:

• Customer relations management software for call center applications

• Interactive voice response systems

• Automatic call distribution

• Unified messaging by integration of voice mail, text-to-speech conversion and so on.

The architecture of a call center using these products is given in the next chapter.

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