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When SCCP will use the Class 1 (Sequenced) connectionless services ?

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ashraf1984
When SCCP will use the Class 1 (Sequenced) connectionless services ?

HI all,W when SCCP will use the Class 1 (Sequenced) connectionless services ? How the orginating subsystem make decison of type of connectio it want to be stup...ie class 0,1,2,3...thanks in advance... Regards,mhd.ashraf

TomiZet
Hi Ashraf, decision has to be

Hi Ashraf, decision has to be done on SW application level by SCCP user depending on what kind of communication SCCP user needs. I will try to illustrate this on TCAP user, TCAP might use 0 or 1:[list][*][b]0 - unacked, no in-sequence delivery[/b][*]default TCAP choice, you send oneTCAP message and expect the answer, thus you do not care about in-sequence delivery. Simply you do not send another message without receiveing answer to the previous one.. Each message of the TCAP dialogue might be routed via different signalling link - each message might have different SLS[*][b]1 - unacked, in-sequence delivery[/b][*]This is used if you want TCAP messages of one dialogue to travel same path - each message of the TCAP dialogue gets the same SLS.[/list]

manas.reddy
how addressing and routing is done in sccp

Hi frnds,can you explain me how addressing and routing is done in sccp with simple example.. i am not understanding?Pls,pls help me thanks,manasreddy

manas.reddy

ashraf1984
Thanks a lot..TomiZet

hi Thanks a lot..TomiZet... i have some more query...Normaly i observerd form the GSM traces MAP messasge (like LU,IMEI check....) are uses connection less services and CAMEL messages uses the connection orianted. is there is any protocole definition that mesages want to use which type of connection..Or its depends on the sending and recieving node (ie if recieving node have a capabltiy of sequencing then use connection less other ways connection orianted...) if so how sending node know the capablity of recieving node.... thnks in advance .....

TomiZet
Hi,  you should not have seen

Hi,  you should not have seen CAP with connection oriented SCCP class.. please check out the TS I meantioned previously and go to the chapter [b]12.2    Services assumed from SCCP[/b] - it refers only to connection-less SCCP services. Read on to the head [b]12.2.2.1.3    Sequence control[/b]. There is explicitely mentioned this: "The application will specify whether SCCP protocol class 0 or 1 is required. Class 0 provides a basic connection less service where the sequence of message delivery is not guaranteed. Class 1 connection less service provides a guaranteed sequence delivery of messages (with the same called address) for a given stream of messages. Class 1 shall be requested by any application that can send more than 1 TC message to its peer (consecutive TR-CONTINUE) before receiving a response from its peer (TR-CONTINUE or TR-END)." So by default class0 shall be used because usually application sends out 1 message and do not send any other msg untill it gets back the answer(or timeout). Only in case 2(or more) messages are send in a row before waiting for answer you need to quarantee in-sequence delivery and thus you need to go for class1. Hope this clears this up...

ashraf1984
Thanks a lot..TomiZet

thanks a lot for your valuable information...