Location
update conception
The UE/USIM is store the LAI when user move MS from one area to another area,so UE/USIM detect the new LAI. In system VLR/MSC storage the LAI number and it communicated by SS7 link.
all those VLR/MSC numbers are stored in HLR system.So when user move from one area to one more area the LAI will update new LAI at that area and it check in VLR/MSC for checking that LAI number,then it also check the VLR/MSC number of that area in HLR sytem.
Normal
location update
One MS move to other area so firstly it send request to BTS part and BSS part for checking the location update request with IMSI,after checking BSS continues sending that Location updating request with IMSI/TMSI, old LAI and current LAI/GCI to MSC,In MSC checks then continues sending to VLR for provide the location update area (IMSI) for MS,then VLR send parameters(IMSI) to HLR/AUC,after checked HLR/AUC send back to VLR with the Authentication parameters with (RAND/SRE S/Kc,IMSI) and VLR also authenticate with MSC and MSC send Authentication request to MS whether allow can do the location update.Then MS send Authentication response to MSC ,then MSC send Authentication response to VLR and VLR can update the location to HLR/AUC,then it send to PVLR for cancel location,PVLR acknowledge the cancel location with HLR/AUC, HLR/AUC insertes subscriber data to VLR and VLR send subscriber data insertion acknowledgement to HLR/AUC, HLR/AUC acknowledge the update location in which HLR that should update.So it set cyphering mode to MSC and also forward new TMSI and update location area acknowled, and MSC continue send the Cypher mode command to MS and MS send back the Cypher Mode complete to MSC,then MSC send back the Location update accepted to MS ,so the location is completed.
Call flow between MSCs
MS Call Another MS in same MSC
There is certainly an example: A men desire to sent his / her friend a letter, while his buddy often take a trip around, how sand fathers for his / her current address.
Important assumption: his mothers and fathers know where they are, and realize how to contact him or her.
MS Call Another MS in same MSC
There may be an instance: A men would like to sent the friend the letter, though his pal often travel around, how can he send the letter on time and the right way?
Answer: ask his mothers and fathers for the current deal with.
Important idea: his mothers and fathers know where he or she is, and know how to contact him.
MS Call Another MS in same MSC
There's an case: A men need to sent their friend any letter, though his friend often travel around, just how can he send the letter with time and correctly?
Answer: consult his mom and dad for their current handle.
Important philosophy: his mom and dad know where he is, and understand how to contact him.
By Facekhmer21
