Hi,
I am a newbie to GSM. can anyone pass me details or links on call forwarding in gsm networks , that is how it works, the exact messaging that takes place between different entities. I am mainly interested to know whether the caller and callee numbers are present in the message when a call is forwarded.
Thanks
Regards
Arpit
call forwarding is a facility which allows to forward the call to another local number (in India only local call fowarding is allowed. we cannot forward the incoming call to an STD number in India).
There are 2 types of call forwarding -- conditional and unconditional.
When A calls B, then the call hits the MSC of B-party. A HLR query is done for B-party. If is the status in HLR for B, is marked as call forward, then the forwarded number is looked for (ie C-party). Then the call is routed to C-party.
In case of call forwarding, a CDR -- CFW is generated at B's MSC, and an MTC CDR at C's MSC.
Mail me if any more information is required. I have working experience on this.
^^ There is an exception. Call will be forwarded at B-MSC only if it is conditional forwarding.
If it is unconditional forwarding, then it will be forwarded by A-MSC.
GSM supports FOUR types of Call Forwarding:
Forward All Calls: This mode forwards each and every call that comes into your GSM number, unconditionally. This is what most people traditionally think of when you mention call forwarding.
Forward if Busy: This mode forwards calls that come into you GSM number when your phone is busy. This means that instead of getting a busy signal, the caller is deflected to a different phone number.
Forward if Not Answered: This mode forwards calls that come into your GSM number when you fail to answer them. This normally occurs after 15 seconds, but you can change this duration (as you will see later).
Forward if Out of Reach: This mode forwards calls that come into your GSM number when your phone is either turned off, or out of the service area (showing No Service).
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