1. USHA: A Practical Vertical Handoff Solution Ling-Jyh Chen, Tony Sun, Mario Gerla Computer Science Department, UCLA

2. MSAN 20052 June 14, 2005 Introduction The emerging network applications  Wireless & Mobility  Multiple network interfacesMobility USHA: A Practical Vertical Handoff Solution

3. MSAN 20053 June 14, 2005 Handoff seamless A seamless handoff is defined as a handoff scheme that maintains the connectivity of all applications on the mobile device when the handoff occurs. Challenges Challenges: maintaining application sessions (e.g. TCP) USHA: A Practical Vertical Handoff Solution

4. MSAN 20054 June 14, 2005 Seamless Handoff Two goals: low latencies and few packet losses Related Work  Network Layer Approaches  MIPv4, IPv6  Upper Layer Approaches  End-to-End Approaches (e.g. Dynamic DNS)  New Session Layer Protocols (e.g. MSOCKS)  Transport Layer Protocols (e.g. TCP-MH and SCTP) Question: Which one are you using? USHA: A Practical Vertical Handoff Solution

5. MSAN 20055 June 14, 2005 USHA: a “simple” and “practical” handoff solution. NAT Server All packets are encapsulated and transmitted using UDP NAT server Applications are bound to the tunnel and transparent to the handoff. Universal Seamless Handoff Architecture USHA: A Practical Vertical Handoff Solution

6. MSAN 20056 June 14, 2005 Experiment Scenario (1) Indoor mobility: Ethernet & 802.11b USHA: A Practical Vertical Handoff Solution

7. MSAN 20057 June 14, 2005 Experiment (1): LOW_to_HIGH USHA: A Practical Vertical Handoff Solution

8. MSAN 20058 June 14, 2005 Experiment (1): HIGH_to_LOW USHA: A Practical Vertical Handoff Solution

9. MSAN 20059 June 14, 2005 Experiment Scenario (2) Outdoor mobility: 802.11b & 1xRTT USHA: A Practical Vertical Handoff Solution

10. MSAN 200510 June 14, 2005 Experiment (2): LOW_to_HIGH USHA: A Practical Vertical Handoff Solution

11. MSAN 200511 June 14, 2005 Experiment (2): HIGH_to_LOW USHA: A Practical Vertical Handoff Solution

12. MSAN 200512 June 14, 2005 Handoff Server Selection k network interfaces on the mobile host n available HS D i,j : the round-trip delay from the i -th interface to the j -th handoff server C i,j : the capacity of the link from the i -th interface to the j -th handoff server USHA: A Practical Vertical Handoff Solution

13. MSAN 200513 June 14, 2005 USHA extensions Real-time compression Intelligent handoff: decide the “best” time and target interface to handoff Account management and access control Traffic encryption Detecting handoff events and performing service adaptation Transcoding according to available bandwidth and MH properties USHA: A Practical Vertical Handoff Solution

14. MSAN 200514 June 14, 2005 USHA extensions Examples:  Traffic encryption: IPsec [6]  Real-time compression: LZO [8]  Intelligent handoff: Wang [18], Chen [ANWIRE’04]  Service adaptation: Chen [QShine’05] USHA: A Practical Vertical Handoff Solution

15. MSAN 200515 June 14, 2005 Some results of service adaptation Vertical Handoff from LOW_to_HIGH USHA: A Practical Vertical Handoff Solution

16. MSAN 200516 June 14, 2005 Some results of service adaptation Vertical Handoff from HIGH_to_LOW USHA: A Practical Vertical Handoff Solution

17. MSAN 200517 June 14, 2005 Conclusions We proposed a practical vertical handoff approach, called USHA. We evaluated USHA via a set of testbed experiments. Future Work:  Extending USHA to support more dynamic network scenarios (e.g. MANET), in which the vertical handoff may occur on application servers, clients, and/or intermediate hosts. USHA: A Practical Vertical Handoff Solution

18. MSAN 200518 June 14, 2005 Thanks! http://www.cs.ucla.edu/NRL USHA: A Practical Vertical Handoff Solution