tailieunhanh - Signaling System No.7 Protocol Architecture And Sevices part 11

Summary SS7 is a data communications network that acts as the nervous system to bring the components of telecommunications networks to life. It acts as a platform for various services described throughout this book. | Summary SS7 is a data communications network that acts as the nervous system to bring the components of telecommunications networks to life. It acts as a platform for various services described throughout this book. SS7 nodes are called signaling points SPs of which there are three types Service Switching Point SSP Service Control Point SCP Signal Transfer Point STP SSPs provide the SS7 functionality of a switch. STPs may be either standalone or integrated STPs SSP and STP and are used to transfer signaling messages. SCPs interface the SS7 network to query telecommunication databases allowing service logic and additional routing information to be obtained to execute services. SPs are connected to each other using signaling links. Signaling links are logically grouped into a linkset. Links may be referenced as A through F links depending on where they are in the network. Signaling is transferred using the packet-switching facilities afforded by SS7. These packets are called signal units SUs . The Message Transfer Part MTP and the Signaling Connection Control Part SCCP provide the transfer protocols. MTP is used to reliably transport messages between nodes and SCCP is used for noncircuit-related signaling typically transactions with SCPs . The ISDN User Part ISUP is used to set up and tear down both ordinary analog subscriber and ISDN calls. The Transaction Capabilities Application Part TCAP allows applications to communicate with each other using agreed-upon data components and manages transactions. Chapter 5. The Public Switched Telephone Network PSTN The term Public Switched Telephone Network PSTN describes the various equipment and interconnecting facilities that provide phone service to the public. The network continues to evolve with the introduction of new technologies. The PSTN began in the United States in 1878 with a manual mechanical switchboard that connected different parties and allowed them to carry on a conversation. Today the PSTN is a network of .