Voice Over IP

INTERWORKING H.323 AND SS7

In Chapter 9, we learned that H.323 (and the supporting protocols, H.225 and H.245) are used to support VoIP in local area networks. In addition, the H.323 Gatekeeper acts as Call Agent with a telephony network, and must therefore be able to correlate H.323 and ISUP message flows. [MA99] has developed the basic scheme for the interworking of H.323 and an SS7 Gateway. In this section, we examine the major features and the protocol flow of the H.323/SS7 Gateway operations. The interworking of H.323 and ISUP is fairly straightforward because the operations of the H Recommendations are similar to ISUP. For example, all of these signaling protocols use the bearer capability concept, so mapping the H.224 SETUP message to ...