Call flow

HI kumaranurag ,

I want to ask u a question about call flow...the scenario is that ...During a MTC for a inroamer, lets

say an outroamer from Indian operator is roaming at Austria. Then during interrogation procedure,

the MS from India calls its ouroaming subscriber in Austria. In that case, the MS in India will use the

MSISDN to locate GMSC.So after identification of GMSC it sends IAM to that GMSC. Then GMSC sends

SRI msg to HLR.

I want to know that does that GMSC and HLR is from India or Austra?

manu

MTC of out roamer

MTC of out roamer:

STEP 1:

A Party ---call--> A Party MSC/VLR ----call---> B Party GMSC ___}----> Call Flow

STEP 2:

B Party GMSC ----sig---> SendRoutingInfo ---sig--> HLR of B ___}----> Signalling

HLR of B ----sig---> SRI Resp ( VLR ) to B Party GMSC ___}----> Signalling

STEP 3:

B Party GMSC --call--> VLR of B ___}----> Call Flow

Hope its clear!

MT-SMS of out roamer

>> Can you help me by explaining the call flow for SMS on out roamer.

It is similar to MTC

STEP 1:

A Party ---mo-sms--> A Party SMSC

STEP 2:

A Party SMSC ----sig query---> SendRoutingInfoForSM ---sig--> HLR of B

HLR of B ----sig query---> SRI Resp ( IMSI+Serv MSC/VLR ) to A Party SMSC

STEP 3:

A Party SMSC --sms-mt--> VLR of B -->mt-sms--> B party

Top

Log in or register to post comments

Tue, 08/24/2010 - 02:59

#9Manu

Regarding inroamer to inroamer

In case of inraomer to inroamer in a VPLMN, after location update , the serving MSC/VLR has the

information of the inraomers right ? as the serving MSC/VLR queries the Home HLR right? But when

MOC from inroamer to inroamer does it again queries the HLR, i am confused about the call flow. Can

u help me?

In my understanding:

step1:

Inraomer A ---call--> serving MSC/VLR ----call---> visiting GMSC ___}----> Call Flow

STEP 2:

Home GMSC ----sig---> SendRoutingInfo ---sig--> home HLR ___}----> Signalling

Home HLR ----sig---> SRI Resp ( VLR ) to home GMSC ___}----> Signalling

STEP 3:

Home GMSC --call--> Visiting GMSC ___}----> Call Flow

STEP 4:

Visiting GMSC--call-->serving visiting MSC/VLR___}----> Call Flow

Is my understanding Okay???

Admin please correct it.

Questioncan u explain call flow for roaming mobile to roamingmobile?(both users are belongs to same state but staying onroaming in different states)

If a Roaming Mobile A call to a roaming mobile B,SRI query

will come to Home HLR,which then provides the exact MSC

address of roaming Mobile B.MSC where Raoming mobile B

present will provide a MSRN Which will be provided to MSC

which is current serving Roaming Mobile A via HLR.

MSRN will be used to route the Call.

 Re: can u explain call flow for roaming mobile to roaming mobile?(both users are belongs to same state but staying on roaming in different states)

Answer# 3

Ex: Assume, A & B subscribers are from Karnataka and A is roaming in Rajasthan and B is roaming in KeralaWhen A calls B1. SRI message with the B MSISDN is sent to Rajasthan GMSC2. Rajasthan GMSC will verify and finds that this call can be handled by the Karnataka GMSC and forwards the request to Karnataka GMSC3. Karnataka GMSC sends forwards the SRI to HLR.4. HLR prepares a search request using the B party MSISDN and fetches the B subscribers details from its database and finds the VLR/MSC number where B is registered (in this ex: Kerala VLR/MSC)5. HLR sends PRN to the local GMSC, which is then frowarded to Kerala GMSC.6. On receiving back the MSRN, HLR sends to the A party GMSC (Rajasthan GMSC)7. Rajasthan GMSC using this MSRN prepares a IAM message and the ISUP trunk is ceased