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Emerged Technologies Signaling System Seven – SS7. Nirmala Shenoy Information Technology Department Rochester Institute of Technology. Signaling System 7. Purpose A Signaling Network Exclusively Telephone networks Can be used for ISDN Setting up and clearing call
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Emerged TechnologiesSignaling System Seven – SS7 Nirmala Shenoy Information Technology Department Rochester Institute of Technology updated 12/2001
Signaling System 7 • Purpose • A Signaling Network Exclusively • Telephone networks • Can be used for ISDN • Setting up and clearing call • Providing special services • Can operate on any link updated 12/2001
Signaling System 7 • Topology • Uses SS7 components , STP, SSP, SCP updated 12/2001
Signaling System 7 • Topology • Subscriber lines are connected to Service Switching Points – SSP • Perform call processing on behalf of user • Implemented at end offices • Source and destination of SS7 messages updated 12/2001
Signaling System 7 • Topology • STP – Signaling Transfer points • Translating SS7 messages • Routing messages • Basic function – relaying between SSP, STP, SCP – layer 3 updated 12/2001
Signaling System 7 • Topology • SCP – Service Control Point • Software & databases for call management • 800 call services – eg • Receive queries and send responses • Components may be co-located updated 12/2001
Signaling System 7 • Layers – MTP 1 • Message Transfer Part 1 • Physical Layer • Electrical attributes, • Connectors datails • Support for digital and analog links updated 12/2001
Signaling System 7 • Layers – MTP 2 • Message Transfer Part 2 • Data Link layer • Transfer of traffic between SS7 components • Similar to HDLC updated 12/2001
Signaling System 7 • Layers – MTP 3 • Message Transfer Part 3 – layer 3 • Network management • Message routing, Route discovery, Routing around • Flow control • Message distribution updated 12/2001
Signaling System 7 • Layers – SSCP • Signaling Connection Control Point – layer 3 • Support connection oriented or connectionless • Translate addresses –SS7 identifiers updated 12/2001
Signaling System 7 • Layers – ISUP • ISDN User Part • Transmit call control between SS7 nodes • Works in conjunction with ISDN Q.931 • Translates Q.931 messages for use in SS7 network updated 12/2001
Signaling System 7 • Layers – TCAP • Transaction Capabilities Application Part – layer 7 • Various use • 800 number transfer support • Syntax definition between communicating components updated 12/2001
Signaling System 7 • Layers – OMAP & ASE • OMAP • Network Management • ASE • User Specific Services support updated 12/2001
Signaling System 7 • PDUs • Link Layer transfers messages of variable length signal units (SUs) • MSU – Message Signal Unit • Transfers the actual signaling message • LSSU Link Status Signal Unit • FISU Fill-in Signal Unit • Provide layer 2 control and status signaling updated 12/2001
Signaling System 7 • Conclusions • Has been a huge success • Applied in different types of networks • Telephone, ISDN, GSM, Satellite signaling • Operate with some of the emerging technologies updated 12/2001