1. * joint work with T. Chen, S. Han, and K. Chow Mobility Support over IEEE 802.11 Wireless Access Networks Shanchieh Jay Yang scyang@ece.utexas.edu Networked Multimedia Research Department Bell Labs

2. Mobility over 802.11 Networks Router AS1 AS2 AS3AS4 MH AS5AS6 Micro-mobility (intra-domain roaming)Macro-mobility (inter-domain roaming) * fixed IP address for MH => continuous session 10.0.1.0/2410.0.2.0/2410.0.3.0/24 10.0.1.139 * Access Server (AS) : Layer 2 bridge + IP forwarding capability home subnetforeign subnet

3. Problem Statement Efficient micro- and macro-mobility support for clients on IEEE 802.11 wireless access networks. Design goals: - simplicity - compatibility - performance enhancement

4. 802.11 Access Network (PubLAN) Router AS2 AS3AS4AS1 MH proxy IAPP handoff MH proxy home subnetforeign subnet * unable to roam to foreign subnet??? ??? MH ?????? traffic to 10.0.1.139 10.0.1.139

5. Mobile IP: IP tunneling Router HA FA1FA2 MH * intra-domain roaming in foreign subnet still needs to re-register. * solves macro-mobility but inefficient for micro-mobility. MH registration tunnel registration MH tunnel

6. Mobile IP + IAPP Extension Router AS2 AS3AS4AS1 HAFA home subnetforeign subnet MH proxy handoff * roaming in the home subnet: set proxy to attract traffic * macro-mobility: Mobile IP (IP tunneling) MH tunnel proxy * micro-mobility: extend IAPP handoff to redirect traffic when roaming within a subnet MH handoff redirect traffic

7. Mobile IP + IAPP Extension Router AS2 AS3AS4AS1 HAFA home subnetforeign subnet MH proxy handoff * roaming in the home subnet: set proxy to attract traffic * macro-mobility: Mobile IP (IP tunneling) MH tunnel * micro-mobility: extend IAPP handoff to redirect traffic when roaming within a subnet MH handoff redirect traffic

8. Supporting Micro/Macro Mobility Representative cases*: –roaming within home subnet –roaming into foreign subnet –roaming within foreign subnet *illustration for supporting non-mobile-IP clients

9. Roaming within Home Subnet Router AS1AS2 MH beacon reassoc MH handoff req handoff ack 10.0.1.139 - proxy ARP for 10.0.1.139 - route to 10.0.1.139 via RF device

10. Roaming into Foreign Subnet Router AS2AS3 MH tunnel registration beacon reassoc handoff (HA,FA) tunnel - proxy ARP for 10.0.1.139 - IP tunnel to FA(AS3) for client 10.0.1.139 - IP tunnel from HA(AS2) for client 10.0.1.139 - route to 10.0.1.139 via RF device HA FA

11. Roaming within Foreign Subnet Router AS2AS3 MH beacon reassoc tunnel AS4 handoff (HA,FA) chg route to MH - proxy ARP for 10.0.1.139 - IP tunnel to FA(AS3) for client 10.0.1.139 - IP tunnel from HA(AS2) for client 10.0.1.139 - route to 10.0.1.139 via AS4 - route to 10.0.1.139 via RF device HAFA

12. Simplicity Only light weight extension/addition in Access Server (AS) (neither router nor client needs to be changed). layer 2 protocol IAPP FA (minimal) + - relay advertisement from other FA - handoff - get HA/FA info - change FA route to client - beacon/re-association - FA advertisement client FA Old AS HA - tunnel registration

13. Compatibility Support both non-mobile- and mobile-IP clients. After re-association and handoff... layer 2 protocol IAPP FA (minimal) + mobile client HA IP tunnel FA advertisement client solicitation/FA advertisement + FA + IP tunnel

14. Performance : Micro-Mobility Signaling path: –faster intra-domain handoff in foreign subnet. –Let n = # hops between FA and HA, IAPP+ : 1(handoff) + 1(chg_rt) = 2 MIP : 1(handoff) + n(tunnel) = n+1 HFA : 1(handoff) + 1 + (tunnel) = 2 + Data Path: –one hop (FA) more than Mobile IP. HAFA n=6

15. Performance : Macro-Mobility Mobility Server (MS) –Signaling path: background signaling to establish a shortcut tunnel to FA. –Data path : compromise between Mobile IP and optimal route update, e.g. HAWAII. –Savings over Mobile IP: n+1 = # hops between MS & HA. 2n-2 for traffic go through the router MS attached to. HAFA MS tunnel data traffic register

16. Future Work (I) Mobility Server : –optimal location to install MS(s)? –optimal selection of MS(s) to register? –tradeoff between "benefit to more traffic" and ”more savings in terms of hop count”. HAFA MS1 tunnel MS2 80% traffic 20% traffic

17. Future Work (II) Client operational mode : –non-Mobile-IP mode : Internet access –Mobile-IP mode : private network access –simultaneous sessions for both type of access? HA/FA selection : –dedicated HA and FA? –load balancing? –hierarchical FA?

18. Summary A proposal which integrates –Mobile IP (macro-mobility), –802.11 handoff capability (micro-mobility). A proposal aiming at a combination of –simplicity, compatibility, and performance. Demonstration –next door...