Switching to VoIP

This is the Title of the Book, eMatter Edition

Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.

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Chapter 2: Voice over Data: Many Conversations, One Network

The distributed nature of VoIP applications makes them preferable to traditional

telephony on a wide area network—but that’s not the only advantage of VoIP on a

WAN. The other great benefit of VoIP—especially in a bandwidth-conservative

WAN—is compression.

The Core and the Edge

At the heart of a network resides the core, or network backbone. In modern IP net-

works, the core serves the purpose of transporting high levels of aggregate traffic

between nodes that are probably not endpoints—that is, they aren’t the hosts where

the traffic originated or the hosts where it is headed, but rather hosts whose purpose

is to forward that traffic along the core network until it needs an exit along the route

to its destination.

Figure 2-6. With a traditional PBX, voice transmission and call management are dependent upon a

route through the voice switch

Figure 2-7. In IP telephony, call management and signaling can be separated from voice

transmission

PBX

Caller Receiver

Call Management

Voice Transmission

Caller Receiver

Call Management

Voice Transmission

VoIP

Server

Caller Receiver

Call Management

Voice Transmission

VoIP

Server