Subject: Mobile Computing

Difficulty: Medium

Marks: 6 Marks

Call termination Step

1: Location query

Step 1.1: The calling party dials the phone number of u1, the request is send to call originating switch to PSTN.Step

Step 1.2: The originating switch sends the location query message to HLR.

Step 1.3: The HLR determines that u1is an overflow user andsend a query message to obtain its routing information. The user profile information is attached in this message.

2: Location Response

Step 2.1: If V is not full, a record for u1is created. If V is full, a user record is deleted and is used to store u1's record. V creates routable address of u1and send back to HLR, if the VLR record is not available, then refer the detail of routable address. If the record is replaced (u3as shown in Fig. ), the replacement information is included in the message.

Step 2.2: The HLR returns the routable address to the originating switch. If the record is replaced, the overflow flagare updated in HLR (for u1and u3as shown in Fig. ).

Step 2.3: The originating switch set up the trunk to the MSC based on routable address.

Step 2.4: The MSC pages the mobile phone and the path for the call is established.