1. Seamless Handover in Terrestrial Radio Access Networks: A Case Study 第 5 組 彭瑱瑞 李政穎 陳冠男 郝晉杰

2. Outline Motivation Mobile IP Mobile IP in WLAN-GPRS environment Interworking between mIP and GPRS entities Simulation Conclusion

3. Motivation An ever-increasing traffic flows over wireless network Existed wireless technology WLAN, Bluetooth, GPRS, …. Two of largest deployed packet-switch technology 802.11 (WLANs) High bandwidth, covers small areas GPRS (WWANs) Low bandwidth, covers large areas

4. Motivation (cont.) Compare between various wireless technology

5. Motivation (cont.) Roaming between GPRS/WLAN Interface change IP Address change Upper layer application (TCP/UDP) disconnect How to Vertical Handovers with Mobile IP

6. Mobile IP Component MN HA FA Operation Agent Discovery Registration Tunneling

7. Mobile IP (cont.)

8. Vertical Handovers with mIP

9. Vertical Handovers with mIP (cont.)

10. Vertical handover vs Mobile IP Vertical handover The mobile node registers its new location while it is still connected through its old access interface Datagrams buffered into the old network that old interface can still reach Very efficient in terms of datagram loss Mobile IP Handover occurs delay and data loss between different IP networks but over the same interface Requires additional mechanisms to reduce delay and data loss

11. Target Usage Scenario Foreign Agent Help MN detect movement Broadcast periodic advertisements and respond to solicitation message Two scenarios Foreign agent lend its IP address as CoA to MN MN can detect movement through other means and acquire an IP address by itself DHCP, PPP

12. Target Usage Scenario (cont.) Another case MH allocated in private IP address Datagram traffic to and from the private CoA is transported over the Internet through IP-in-IP tunnels established between public endpoints

13. Interaction between MH and GPRS Interaction between MH Emulate laptop and GPRS handset as a PPP connection To get IP address PPP phase  LCP (Link Control Protocol)  PAP (Password Authentication Protocol)  IPCP (Internet Protocol Control Protocol) Foreign agent discovery Standard ICMP router discovery cannot be employed Different protocol stack between IP Network and GPRS long-haul message Derives from standard ICMP message Unicast message

14. Interaction between MH and GPRS TEMTGGSN Radius Server FA LCP negotiation PCP negotiation PDP context activation Radius authorization FA notification Long-haul unicast agent advertisement Mobile IP registration Interaction between the mobile node, foreign agent, and GGSN

15. Simulation

16. Simulation (cont.)

20. Conclusion Seamless communication in a heterogeneous networking environment Mobile IP: ensure IP-level connectivity Vertical handover: ability to use multiple access interfaces at one