Cellular IP

1. Cellular IP Myungchul Kim mckim@icu.ac.kr

2. seamless mobility support • picocellular environment • address translation in Mobile IP • Mobile IP is not appropriate for seamless mobility: registration between MN and HA • paging, passive connectivity -> scalability • Mobile IP does not support the notion of seamless mobility, passive connectivity, or paging • Related Work • Mobile IP is extended by arranging FAs in a hierarchy [6, 8] • Cellular IP • employ per-mobile-host states • hop-by-hop routing to achieve fast handoff control • passive connectivity: reduce the search time and increase protocol scalability • a layer three routing protocol

3. Hawaii [5]: Hawaii nodes are IP routers • the use of explicit signaling messages is limited in Cellular IP • minimizing service disruption during handoff • Cellular IP handoff aims at simplicity, eliminating the reliance on multicast and minimizing explicit signaling • Protocol Overview • The Network Model • For base station, IP routing is replaced by Cellular IP routing and location management. • without tunneling or address conversion • to minimize control messages, regular data packets transmitted by mobile hosts are used to refresh host location information: uplink and downlink

4. Routing • each base station maintains a routing cache • mapping (X, BS3) at BS2 in Figure • route-time-out, route-update packet and route-update time.

5. Handoff: hard handoff and semisoft handoff • Hard Handoff • handoff latency: the round-trip time between the mobile host and the crossover base station • only a local node has to be notified rather than a possibly distant HA in the case of Mobile IP • way to reduce packet loss: interaction between the old and new base stations during handoff

6. Semisoft handoff • the routing cache mapping associated with the new base station must be created before the actual handoff takes place. • a constant delay along the new path between the crossover and new base stations • Paging • paging-update, paging-update-time, paging-cache, paging-timeout

7. Security • impersonation and snooping attacks • only control packets are authenticated • Evaluation • Testbed • FreeBSD 2.2.6, Windows and Linux • Berkeley Packet Filter’s Packet Capture Library (PCAP) • WaveLAN I, II • a utility tool for manual handoff

8. Handoff • ttcp: TCP performance • UDP Performance • handoffs every 5s and 50 consecutive handoffs

9. TCP Performance

10. Scalability

11. Further work • QoS provisioning for mobile multimedia • wireless differentiated services to mobile hosts • link and node failure • multiple gateways

12. A Direct Routing Scheme In Cellular IP Access Network Sang-ick Byun and Myungchul Kim {sibyun, mckim}@icu.ac.kr

13. Contents • Introduction • Related Work • Cellular IP Routing Scheme • Proposal of Direct Routing Scheme • Implementation • Experimental Results • Conclusion • References

14. Introduction • Development of wireless technology and expansion of the Internet - Increasing demand on mobile and wireless data service - Internet Protocol (IP) was designed without consideration of mobility • Mobile IP (RFC 2002) • Solve the macro mobility management • The mobile nodes can use the existing IP without session interruption while the devices are moving • It is less well suited for micro mobility management problem

15. Introduction (cont’d) • Micro mobility protocols such as [2][5][8][15] have been proposed • We focus on Cellular IP • Routing policy: All packets transmitted by mobile host should be delivered to the gateway • Communication between mobile hosts within same Cellular IP access network path duplication problem • We propose a direct routing scheme

16. Related Work • C. Perkins, “IP Mobility Support” [11] • IETF RFC 2002 (1996) • Tunneling from HA to FA • registration request , registration replay  It is less well suited for “micro mobility” • Micro mobility : frequent handoffs between small cells • Handoff delay and service quality degradation • R. Caceres and V. N. Padmanabhan, “Fast and Scalable Handoffs for Wireless Internetworks” [2] • Hierarchical mobility management scheme • Local mobility, mobility within an administrative domain, global mobility • One domain foreign agent and several subnet foreign agent

17. Related Work (Cont’d) • E. Gustafsson et al., “Mobile IP Regional Registration”[8] • Gateway foreign agent (GFA) • When the mobile host registers to its HA, MH uses the address of GFA • After the first registration, MH performs a local registration with the GFA • R. Ramjee et al., “HAWAII: A Domain-based Approach for Supporting Mobility in Wide-area Wireless Networks”[15] • Routing protocol for intra-domain mobility • Domain root router • HAWAII nodes : router + location manager using cache

18. CH HA FA FA BS BS BS BS BS BS MH Internet Cellular IP access network IP routing IP tunneling Cellular IP routing Cellular IP Routing Scheme • Cellular IP Access Network

19. GW BS1 BS2 BS3 MH1 MH2 Cellular IP Routing Scheme (cont’d) • Cellular IP routing • Uplink routing : Routing from a mobile host to a gateway • Downlink routing : Routing from a gateway to a mobile host • Uplink routing • All packets received from downlink neighbor used to manage a route cache and paging cache • After that, packet is forwarded to uplink

20. Cellular IP Routing Scheme (cont’d) • Downlink routing • Routing from a gateway to a mobile host Entry? YES Forward the packet to downlink neighbor Check route cache NO YES Does BS have a paging cache? Check paging cache NO Entry? YES Broadcast Forward to downlink neighbor Check paging cache NO Discard packet

21. Proposal of Direct Routing Scheme • Routing policy of existing Cellular IP • All IP packets transmitted by a mobile host are routed from the BS to the gateway regardless of the destination address • Why? All IP packets are used to manage route cache or paging cache • Limitations of existing Cellular IP • CASE : Communication between mobile hosts within same Cellular IP access network • PROBLEM • routing path duplication • Cutting off the routing path

22. Proposal of Direct Routing Scheme(Cont’d) • Example X:N Y:N Z:Q X:A Y:A X:S X:O Y:R Mobile IP enabled Internet GW A M N O P Q R S Z Y X route cache Receiver Sender data

23. Proposal of Direct Routing Scheme(Cont’d) • Proposed Scheme • When a packet is received, a Cellular IP node checks its cache mapping • If the Cellular IP node finds the cache mapping for destination address of the packet • The data packet is forwarded to downlink neighbor directly • sends route-refresh packet or pseudo data packet to uplink neighbors • If the Cellular IP node can’t find the cache mapping for destination address • The packet is forwarded to up-link neighbor

24. Route-refresh Proposal of Direct Routing Scheme(Cont’d) • Direct routing scheme using route-refresh packet X:A Y:A X:N Y:N X:O Y:R X:O Y:R X:S X:S Mobile IP enabled Internet GW A M N O P Q R S Y X Receiver Sender

25. X:A Y:A X:S X:N Y:Q X:O Y:R Mobile IP enabled Internet GW A M N O P Q R S route cache data Y Y X route-refresh packet Receiver Sender Proposal of Direct Routing Scheme(Cont’d) • Limitation of route-refresh packet • some packets are lost during handoff

26. X:A Y:A X:S X:N Y:Q X:O Y:R Mobile IP enabled Internet GW A M N O P Q R S Y Y X routing cache data Receiver Sender Proposal of Direct Routing Scheme(Cont’d) • Direct routing scheme using pseudo data packet • If a BS forwards the packet to downlink neighbor directly, the BS sends pseudo data packet to uplink neighbor

27. Internet Implementation • Consists of four Cellular IP nodes and two mobile hosts • Each BS and MH run Linux (kernel 2.2.12) • IEEE 802.11b WaveLAN PC Cards are installed at BS_2, BS_3, MH_1, and MH_2 • Our scheme is implemented based upon Cellular IP 1.1 distribution • Testbed architecture GATEWAY Cellular IP Access Network BS1 BS2 BS3 MH1 MH2

28. GW BS1 BS2 BS3 MH1 MH2 Experimental Results • CPU usage ratio (per a MH) (a) 400 packets/sec (b) 600 packets/sec • MH_1 sends 128byte UDP packets to MH_2 at rate of 400 and 600 packets/sec • Each BS monitor the CPU usage ratio during 30 seconds • RESULT : CUP usage ratio is reduced in GW and BS_1

29. GATEWAY GATEWAY BS1 BS1 BS2 BS3 BS2 BS3 Data Data MH1 MH2 MH1 MH2 Experimental Results (cont’d) • Robustness (a) Existing Cellular IP (b) Proposed Scheme • The gateway stop running in the middle of packet transmission from MH_1 to MH_2. • In existing Cellular IP scheme, packets are not delivered after that time • In proposed scheme, all packets are delivered without any interruption

30. GW BS1 BS2 BS3 MH1 MH2 Experimental Results (cont’d) • Bandwidth consumption using VIC (a) gateway (b) BS_1 (c) BS_2 (d) BS_3 • The experiment is carried out using VIC 2.8ucl-1.1.3, in order to measure the performance of practical application • The sender, MH_1, is equipped with a capture board and a video camera • While video data is transmitted from MH_1 to MH_2, the Cellular IP nodes monitor bandwidth consumption in each network interface. • RESULT : Bandwidth consumption between crossover BS and gateway is reduced by 50%

31. GW BS1 BS2 BS3 MH1 MH2 Experimental Results (cont’d) • Packet loss with handoff • The sender, MH_1, sends 100byte UDP packets at rates of 25, 50, 100, and 150 packet/sec • MH_2 handoffs between BS_2 and BS_3 every five seconds • The UDP packets are transmitted for 100 seconds and MH_2 handoffs 20 times • RESULT : Our scheme does not deteriorate the existing Cellular IP in terms packet loss with handoff

32. Conclusion • Advantages of a direct routing scheme - Mobile host use shortest path within Cellular IP access network - Resource saving in BSs between gateway and crossover BS • CPU time for packet processing is reduced • Bandwidth consumption is reduced - Robustness is high • Future work - Enlargement testbed - Studies the effects of proposed scheme on multimedia applications

33. References [1] M. Albrecht, M. Frank, P. Martini, M. Schetelig, A. Vilavaara, and A. Wenzel, “IP Services over Bluetooth: Leading the Way to a New Mobility,” Conference on Local Computer Networks (LCN '99), 1999 [2] R. Caceres and V.N.Padmanabhan, “Fast and Scalable Handoffs for Wireless Internetworks,” ACM Conference on Mobile Computing and Networking (Mobicom’96), 1996. [3] C. Castelluccia, “Extending Mobile IP with Adaptive Individual Paging: A Performance Analysis,” Computers and Communications, Proceedings. ISCC 2000. Fifth IEEE Symposium Page(s): 113 –118, 2000 [4] S. Das, A. Misra, S. K. Das, and P. Agrawal, “TeleMIP: Telecommunication-Enhanced Mobile IP Architecture for Fast Intradomain Mobility,” IEEE Personal Communications, Aug. 2000 [5] A. T. Campbell, J. Gomez, S. Kim, Z. Turanyi, C-Y. Wan, and A. Valko, “Design, implementation, and evaluation of cellular IP,” IEEE Personal Communications, Vol.7 Issue. 4, Aug. 2000, pp. 42 –49 [6] A.T. Campbell, J. Gomez, C-Y. Wan, S. Kim, Z. Turanyi, and A. Valko, "Cellular IP," Internet Draft, draft-ietf-mobileip-cellularip-00.txt, January 2000. [7] A. T. Campbell, S. Kim, J. Gomez, C-Y. Wan, Z. Turanyi, and A. Valko, “Cellular IP Performance,” draft-gomez-cellularip-perf-00.txt, Oct. 1999 [8] E. Gustafsson, A. Jonsson, and C. Perkins, “Mobile IP Regional Registration,” Internet Draft, draft-ietf-mobileip-reg-tunnel-04.txt, March 2001; work in progress [9] C. Perkins and D.B. Johnson, “Route Optimization in Mobile IP,” Internet Draft, draft-ietf-mobileip-optim-09.txt, Feb. 2000.

34. References (Cont’d) [10] C. Perkins and D.B. Johnson, “Mobility Support in Ipv6,” Internet Draft, draft-ietf-mobileip-ipv6-07.txt, 1998. [11] C. Perkins, “IP Mobility Support,” IETF RFC 2002, Oct. 1996 [12] J. Postel, “Internet Control Message Protocol,”, IETF RFC 792, Sep. 1981 [13] J. Postel, “User Datagram Protocol,” IETF RFC 768, Aug. 1980 [14] R. Ramjee, T. F. La Porta, L. Salgarelli, S. Thuel, and K. Varadhan, “IP-Based Access Network Infrastructure for Next-Generation Wireless Data Networks,” IEEE Personal Communications, Vol.7 Issue. 4, Aug. 2000, pp. 34-41 [15] R. Ramjee, T. La Porta, S. Thuel, K. Varadhan, and S.Y. Wang, “HAWII: A Domain-based Approach for Supporting Mobility in Wide-area Wireless Networks,” IEEE International Conference on Network Protocols, 1999. [16] András G. Valkó, "Cellular IP: A New Approach to Internet Host Mobility," ACM Computer Communication Review, Jan. 1999. [17] The MGEN Toolset, http://manimac.itd.nrl.navy.mil/MGEN/ [18] Instruction to Mobile IP, http://www.cisco.com [19] Mbone Conferencing Applications, http://www-mice.cs.ucl.ac.uk [20] Cellular IP, http://www.comet.columbia.edu/cellularip