INTER-OPERATOR SMS FLOW

 

 

 The above fig illustrates the scenario where sms originates from GSM network and deliverd to

different GSM network.

MS ORIGINATES SMS

NOW MSC A FORWARDS THE PACKET TO SMSC-A THROUGH MO-FORWARD-SM MESSAGE

FOR ROUTING IT USES SCCP CALLING ADDRESS: GT OF MSC AND SCCP CALLED ADDRESS

GT OF SMSC(SERVICE CENTRE ADDRESS)

MO-FORWARD-SM MESSAGE CONTAINS: SMS, A NUMBER, B NUMBER, SC ADDRESS

SMSC AFTER CHECKING BASIC AUTHENTICATION, RESPONDS WITH MO-FORWARD-SM-

ACK

ONCE THIS ACK REACHES TO HANDSET, ORIGINATOR KNOWS THAT HIS MESSAGES HAS

BEEN DELIVERED INTO THE SMSC

SMSC NEEDS TO KNOW THE SUBSCRIBER B LOCATION TO ROUTE THE SMS TO B NUMBER.

SO IT DOES SRI (SEND ROUTING INFORMATION) QUERY .

SO SMSC WILL CONNECT TO HLR DIRECTLY OR WILL GIVE TO THE GATEWAY MSC TO SEND

THE SRI QUERY TO B PARTY NETWORK.

FOR ROUTING WE USE SCCP CALLING ADDRESS: UNIQUE GT OF SMSC AND SCCP CALLED

ADDRESS: SUBSCRIBER NUMBER + SSN 6

B PARTY HLR AFTER RECEIVES THE SRI QUERY , IT RESPONDS BACK WITH THE SRI-ACK.

FOR ROUTING PURPOSE SCCP CALLING ADDRESS: GT OF HLR AND SCCP CALLED ADDRESS:

UNIQUE GT OF SMSC IS USED

ONCE THE LOCATION AND AVAILABILITY OF B PARTY IS KN OWN THROUGH SRI-ACK .

SMSC NEEDS TO FORWARD THE SMS TO MSC/VLR-B. MT-FSM(MT-FORWARD-SM)

SCCP CALLING ADDRESS: GT OF SMSC AND SCCP CALLED ADDRESS: GT OF NODE WHICH

SMSC HAS RECEIVED IN SRI-ACK IS USED FOR ROUTING

REMOTE MSC/VLR WILL RESPOND BACK (MT-FSM-ACK) USING SCCP CALLING ADDRESS:

GT OF MSC/VLR AND SCCP CALLED ADDRESS: GT OF SMSC

RESPONSE MESSAGE HAS INFORMATION ABOUT SUCCESS/FAILURE OF SMS TO B PARTY

NUMBER.