Basic GSM Call Flow
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Transcript of Basic GSM Call Flow
With traces from Huawei MSOFT
BASIC Call Flow Basic Call Flow
1. Location Update2. MOC TDM3. MOC IP4. MTC TDM5. MTC IP
Basic Call Flow
Location Update (LOC UP)
Location Update
LOC Up: Identity Response
LOC UP: Authentication
LOC UP: AUC Internal Structure
IMSI Ki
RANDOM number
generatorRAND
SRES
Kc
Ki
MSCHLR
AUC
IMSIIMSI
A3
triplet triplet
A8
LOC UP: Authentication
LOC UP: Authentication
MSC RAND SRES
Kc
RAND
SIM
RAND
Ki
A3
A8
SRES
SRES
Kc
SRES = SRES?
LOC UP: Authentication Request
LOC UP: Authentication Response
LOC UP: Update Location Req
LOC UP: Insert Subscriber Data
LOC: IMEI receive
LOC UP: Ciphering
LOC UP: TMSI Reallocation
Basic Call Flow
Mobile Originating Call (MOC)
MOC: Complete call Trace
CM Service Request
MOC : “Setup” MessageSetup message contains the dialed number from the Mobile station (MS)
MOC: (SRI) Send Routing Information
MOC: Reply from HLR
Assignment Request
MOC: IAM – Initial Address Message
MOC: ACM – Address Complete Message
MOC: Connect & Release
Basic Call Flow
Mobile Terminating Call (MTC)
MTC: Complete Trace
MTC: Provide Roaming Number (PRN)
MTC: PRN Response
MTC: IAM
Paging Request
Paging Response
Set UP
IP CALL
Call Flow through IP( MOC)
BICC TYPE IAM
TO BICC TYPE APM
FROM BICC TYPE APM
Call Flow through IP( MTC)
PRN
PRN Response
BICC TYPE IAM
Set UP
TO BICC TYPE APM
FROM BICC TYPE APM
Assignment Request
ALERT AND BICC TYPE ACM
CONNECT AND BICC TYPE ANM
DISCONNECT AND RELEASE
THANK YOU