location updation in GSM network

hi,

i want to know how a location updation takes place in the mobile communication and thier internal protocols tht handle the location updation in a GSM network?

with regards
ram

Location update were done by the BTS with regards to your mobile phone by periodically interrogating it and update the HLR or the VLR in the MSC
With the RTS there is a signalling channel that is responsible for this and I thinks this is what they call LaPd .