LTE: How does TAU procedure work ?

Question

Answer 1

one TAL(tracking area list) compose of a group of TA. The UE will send the location query to the MME, if the UE is in idle mode and acrossing the boundary of the TAL

Answer 2

If you are looking for the message flow, please refer to 3gpp spec 23.401 and go to Tracking Area Update procedure