In today's technological world,mobile phones have become part and parcel of our lives.But have we ever thought ,when we call someone,how does our call reach the right person sometimes living long distance apart......
But finally I got answer to my question...
I earlier used to think that when we make a call it goes to the cell tower..yes u are guessing it right..the big towers with antennas which you can find on roof tops,shop tops etc..but that is not it ... So here it goes.....
First when we make a call,each handset has a MIN(mobile identification number) andSIM(sim identification number).which is conveyed to the tower along with your call signal ..The tower sends back acknowledgement signal to the mobile..so DUPLEX channel is used..for this transferring ,You must be wondering what DUPLEX channel is??
As name suggest it is a channel,where one path is reserved for sending signal to tower and another path is used to send acknowledgement signal.
Now after your call signal reaches cell tower which is also called BSC..it goes to MSC(mobile switching center) ..MSC actually acts as router or you can say a switch which sends your signal first for verification, ie to VLR( verification location register) which is actually a sub register..
Well let me explain in detail............
When you get prepaid card the carrier company asks you to fill in details..that details goes to a big register called HLR(home location register)..
From there, data is divided according to different region and send to various VLR..so ,from there MSC checks whether person is at roaming or not..
After that the call is send to the nearest MSC of the person you want to call and from there call is send to the nearest tower of the person you are calling.. And finally call is received...
This is how call reaches from source to destination.....
I hope you guys could understand..This whole call forwarding process I told above is part of PUBLIC SWITCHED TELEPHONE NETWORK which consist of telephone wires,fibre optics,cables,microwave transmission....And whatever explained above is just like a drop in the ocean..as networking is vast subject and it is not possible to cover each point...
But finally I got answer to my question...
First when we make a call,each handset has a MIN(mobile identification number) andSIM(sim identification number).which is conveyed to the tower along with your call signal ..The tower sends back acknowledgement signal to the mobile..so DUPLEX channel is used..for this transferring ,You must be wondering what DUPLEX channel is??
As name suggest it is a channel,where one path is reserved for sending signal to tower and another path is used to send acknowledgement signal.
Now after your call signal reaches cell tower which is also called BSC..it goes to MSC(mobile switching center) ..MSC actually acts as router or you can say a switch which sends your signal first for verification, ie to VLR( verification location register) which is actually a sub register..
Well let me explain in detail............
When you get prepaid card the carrier company asks you to fill in details..that details goes to a big register called HLR(home location register)..
From there, data is divided according to different region and send to various VLR..so ,from there MSC checks whether person is at roaming or not..
After that the call is send to the nearest MSC of the person you want to call and from there call is send to the nearest tower of the person you are calling.. And finally call is received...
This is how call reaches from source to destination.....
I hope you guys could understand..This whole call forwarding process I told above is part of PUBLIC SWITCHED TELEPHONE NETWORK which consist of telephone wires,fibre optics,cables,microwave transmission....And whatever explained above is just like a drop in the ocean..as networking is vast subject and it is not possible to cover each point...
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