Signalling Connection Control Part: Difference between revisions

Revision as of 13:45, 9 December 2021

Revision as of 19:08, 21 August 2023

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==Routing facilities beyond MTP==

Although [[Message Transfer Part|MTP]] provides routing capabilities based uponon the [[Point Code]], SCCP allows routing using a [[Point Code]] and [[Subsystem number]] or a [[Global Title]].

A Point Code is used to address a particular node on the network, whereas a [[Subsystem number]] addresses a specific application available on that node. SCCP employs a process called [[Global Title Translation]] to determine [[Point Code]]s from [[Global Title]]s so as to instruct [[Message Transfer Part|MTP]] on where to route messages.

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==Protocol classes==

SCCP provides 4 classes of protocol tofor its applications:

* '''Class 0''': Basic connectionless.

* '''Class 1''': Sequenced connectionless.

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===Class 0: Basic connectionless===

The SCCP Class 0 protocol class is the most basic of the SCCP protocol classes. Network Service Data Units passed by higher layers to the in the originating node are delivered by the SCCP to higher layers in the destination node. They are transferred independently of each other. Therefore, they may be delivered to the SCCP user out-of-sequence. Thus, this protocol class corresponds to a pure [[connectionless protocol|connectionless network service]]. As a connectionless protocol, no network connection is established between the sender and the receiver.

===Class 1: Sequenced connectionless===