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Figure 33.1 |
Conceptual organization of the most basic IP telephone system. An IP telephone uses the controller to find another IP telephone and establish a call. |
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Figure 33.2 |
The interconnection of an IP telephone system with the Public Switched Telephone Network. Gateways handle both voice and signaling. |
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Figure 33.3 |
The set of protocols various groups have proposed for use with IP telephony and the layer at which each operates. |
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Figure 33.4 |
The layering of some of the protocols that comprise the H.323 standard. |
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Figure 33.5 |
The six basic SIP methods. |
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Figure 33.6 |
An example of the messages exchanged by SIP to set up a telephone call. |
