TABLE OF CONTENTS This chapter approaches the discussion of application of IPv6 to VoIP by reviewing some of the information that was introduced in Chapter 6 from a more-applied perspective than done in that chapter, and discuss these issues in the context of a VoIPv6 environment.
Figure 7.1 depicts typical Network Elements found in an enterprise network, many of which come into play in VoIP environments. A number of these will need to support IPv6, particularly those that operate at Layer 3 of the protocol model. Figure 7.2 depicts the medium-stage environment IPv6/VoIP under discussion. The idea is that:
any telephone device shown can freely, easily, and reliably communicate with any other telephone at any point at any time; and,
whenever possible, an end-to-end IP-based path should be taken by the call, if a path exists (naturally, telephone sets that are hard-wired to the PSTN have no choice but to use the PSTN at least for a portion of the call path).
At the graphical level Figure 7.2 illustrates how a 3G VoIP based on IPv6 will operate. As seen in this figure, many of the VoIP elements discussed in Chapter 1, Chapter 2, and Chapter 5 need to be upgraded to support IPv6 and/or dual-stacks. As we noted in Chapter 3, SIP operates in either environment (also see Figure 5.8). SIP UAs (User Agents) often support different network address...
