Signalling Connection Control Part

Signalling Connection Control Part ( SCCP abbreviated ) is in telecommunication networks such as the telephone network, as part of the Signaling System 7 ( abbreviated as SS7) network layer used. It is used in the signaling network routing, error correction and flow control, and sets in the context of the OSI layer model on the Message Transfer Part (MTP ) Level 3 (MTP Level 3, MTP -3).

The original specifications of SCCPs have been set for the fixed line segment by the ITU- T as part of the standards Q.711, Q.714 and Q.715. There are also additional regional extensions, as in Europe by the European Telecommunications Standards Institute (ETSI ) ETSI EN 300-009-1 and published in the U.S. by the American National Standards Institute (ANSI) standard T1.112 the. Further enhancements are made such as the Generic Signalling Transport Service, which allows SCCP over the Internet Protocol ( IP) and connects to the IP telephony. It is to be given places in the standard Q.2150.0.

Routing

An essential function of SCCP is a MTP -3 addition, continuous routing. SCCP provides the best possibilities, under the technical terms such as Point Code (PC), Subsystem Number ( SSN ) or Global Title (GT ) are summarized.

A point code in the SS7 addressed a specific network node, during Subsystem Number references a particular application at the network node. Global Title is used to globally identify the point codes for Mediation. The news of SCCP consist of various parameters (indicators ) such as the Address Indicator, Global Title Indicator and the routing indicator.

Protocol classes

SCCP is divided to the separation of functions in different protocol classes:

  • Class 0: Connection-free basic service (English Basic connectionless ): Longer messages can be shared. Then higher layers are responsible for the correct composition of these parts
  • Class 1: Connectionless service with sequence numbers (English Sequenced connectionless ): This number ( SLS ) code is 4 or 8 bits long (ITU -T or ANSI standard). The collection of messages use the same SLS code. If several compounds ( linkset ) used for a message, the sequence number is different in the least significant bits.
  • Class 2: Connection-oriented basic service (English Basic connection- oriented ): The signaling connection has to be assembled and disassembled.
  • Class 3: Connection-oriented basic service with flow control (English Flow control connection oriented ).

Swell

  • Network protocol
  • Telecommunications
  • Switching technology
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