tailieunhanh - Signaling System No.7 Protocol Architecture And Sevices part 26

Summary ISUP provides a rich network interface to call processing at an SSP. The increased bandwidth and protocol standardization allow a greater range of services that are able to interwork both within a network and across network boundaries | Summary ISUP provides a rich network interface to call processing at an SSP. The increased bandwidth and protocol standardization allow a greater range of services that are able to interwork both within a network and across network boundaries. ISUP was designed to interface well with ISDN access signaling by providing event mapping and facilitating end-to-end user signaling. The protocol s use of optional message parameters achieves flexibility and extensibility. ISUP uses a CIC identifier in each message to correlate the signaling with the correct circuit. The CIC is the key to associating signaling with bearer circuits. ISUP also provides a set of maintenance messages for diagnostics and maintenance of ISUP facilities. These messages allow for blocking testing and resetting circuits and inquiring about circuit status. Chapter 9. Signaling Connection Control Part SCCP The Signaling Connection Control Part SCCP is defined in ITU-T Recommendations 58-63 and for North American markets in ANSI 2 . SCCP sits on top of Message Transfer Part 3 MTP3 in the SS7 protocol stack. The SCCP provides additional network layer functions to provide transfer of noncircuit-related NCR signaling information application management procedures and alternative and more flexible methods of routing. NOTE Technically SCCP can also transfer circuit-related signaling information however this is an exception. As shown in Figure 9-1 the combination of the MTP and the SCCP is termed the Network Service Part NSP . The NSP follows the principles of the OSI reference model as defined in Recommendation 99 as such it provides a subset of the Layer 3 services which are defined in Recommendation 100 . Figure 9-1. SS7 Stack with the Network Service Part NSP Highlighted SCCP was developed after the MTP and together with the MTP3 it provides the capabilities corresponding to Layer 3 of the OSI reference model. Because SCCP is OSI Layer 3 compliant in theory it can be .