Signalling Message Flow for GPRS Attach

Presented By

Ben Caddick

Senior MPC Engineer

MS RNC SGSN HLR1. RRC Connection Establishment

1. UE sets up the necessary RRC (Radio Resourse Connections) in the RAN.

MS RNC SGSN HLR1. RRC Connection Establishment

2. Ue sends an attach request to the SGSN, identity used is the IMSI. We need to assume here that this is the first attach to the network and the

User has no such temporary identity available.

2. Attach (IMSI, DRX, CKSN, CN capability

MS RNC SGSN HLR1. RRC Connection Establishment

3. SGSN and UE perform necessary security procedures.

2. Attach (IMSI, DRX, CKSN, CN capability

3. Security Functions

MS RNC SGSN HLR1. RRC Connection Establishment

4. SGSN updates UE’s location to the HLR (IMSI, SGSN number, address).

2. Attach (IMSI, DRX, CKSN, CN capability

3. Security Functions

4. Update Location

MS RNC SGSN HLR1. RRC Connection Establishment

5. HLR sends Update Location Information to the SGSN, which duly acknowledges.

2. Attach (IMSI, DRX, CKSN, CN capability

3. Security Functions

4. Update Location

5. Insert Subscriber data

Acknowledge

MS RNC SGSN HLR1. RRC Connection Establishment

6. SGSN sends Update Location acknowledge.

2. Attach (IMSI, DRX, CKSN, CN capability

3. Security Functions

4. Update Location

5. Insert Subscriber data

Acknowledge

6. Update Location Ack

MS RNC SGSN HLR1. RRC Connection Establishment

7. SGSN sends Attach Accept to the UE. This contains new P-TMSI and P-TMSI signature, which the UE must acknowledge.

2. Attach (IMSI, DRX, CKSN, CN capability

3. Security Functions

4. Update Location

5. Insert Subscriber data

Acknowledge

6. Update Location Ack

7. Attach Accept

MS RNC SGSN HLR1. RRC Connection Establishment

8. The UE acknowledges receipt of Attach Accept with the Attach Complete Message.

2. Attach (IMSI, DRX, CKSN, CN capability

3. Security Functions

4. Update Location

5. Insert Subscriber data

Acknowledge

6. Update Location Ack

7. Attach Accept

8. Attach complete

MS RNC SGSN HLR1. RRC Connection Establishment

9. SGSN releases IU bearers.

2. Attach (IMSI, DRX, CKSN, CN capability

3. Security Functions

4. Update Location

5. Insert Subscriber data

Acknowledge

6. Update Location Ack

7. Attach Accept

8. Attach complete

9. IU Release

MS RNC SGSN HLR1. RRC Connection Establishment

10. RAN releases RRC connections.

2. Attach (IMSI, DRX, CKSN, CN capability

3. Security Functions

4. Update Location

5. Insert Subscriber data

Acknowledge

6. Update Location Ack

7. Attach Accept

8. Attach complete

9. IU Release

10. RAN releases RRC connections