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Routing Issues in Mobile IP

Routing Issues in Mobile IP. Sudarshan Vasudevan Chun Zhang. PART 1. Unicast Routing using Mobile IP. Terminology. Care-of-Address Tunneling DHCP (Dynamic Host Configuration Protocol) HA - Home Agent FA - Foreign Agent MH - Mobile Host CH - Correspondent Host. 1. Overview.

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Routing Issues in Mobile IP

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  1. Routing Issues in Mobile IP Sudarshan Vasudevan Chun Zhang

  2. PART 1 Unicast Routing using Mobile IP

  3. Terminology • Care-of-Address • Tunneling • DHCP (Dynamic Host Configuration Protocol) • HA - Home Agent • FA - Foreign Agent • MH - Mobile Host • CH - Correspondent Host

  4. 1. Overview • Mobile IP • Provide Host Migration Transparency • small modifications to IP routing is sufficient • Involves 3 basic functions • Advertisement • Registration • Tunneling

  5. Protocol • When MH is in its home network • Normal IP Routing • When MH is away from it home network • HA keeps track of MH’s care-of-address • either FA’s IP address or one obtained using DHCP • Care-of-Address represents the MH’s current location • When the MH migrates into another foreign network, MH notifies its new care-of-address to the HA

  6. Example

  7. Tunneling & Triangular Routing

  8. Tunneling & Triangular Routing

  9. Route Optimization • Triangular path is not optimal route • Route Optimization • Supply binding update to CHs • authentication and replay protection for binding updates • registration key between MH and FA for smooth handoff

  10. Route Optimization

  11. Smooth Hand-Off

  12. Conclusion • Triangular Routing can be eliminated • sending binding updates to CHs • Smooth handoffs very valuable • counteract unwanted effects of dropped packets • special tunnels can further reduce this effect • Main difficulty • establishment of security associations between FA and MH

  13. Future Work • Mobility Security Association Management • authentication of all messages that affect routing • currently manual establishment of MSAs • difficult to manage, no scalability • efficient Key Distribution Protocols needed • Certification of Foreign Agents • prevent malicious nodes pretending as FAs • Security issues introduced by Tunneling

  14. References • Perkins, Charles E., ed. “Ipv4 Mobility Support” RFC 2002. October 1996b. • Perkins, Charles E. “Minimal Encapsulation within IP”. RFC 2004.October 1996c. • Perkins, Charles E. “IP Encapsulation within IP”. RFC 2003. October 1996a. • Perkins, Charles E and Johnson, David B. “Mobility Support in IPv6.” In ACM Mobicomm96. November 1996. • Johnson, David B. “Scalable and Robust Internetwork Routing for Mobile Hosts” In Proceedings of the 14th International Conference on Distributed Computing Systems. June 1994. • Hanks Stan, Tony Li, Dino Farinacci, and Paul Traina,Generic Routing Encapsulation over IPv4 networks. RFC 1702. October 1994b. • Deering, Stephen E., ed., “ICMP Router Discovery Messages.” RFC 1256. September 1991. • Hellman, M.E., W.Diffie, and R.C. Merkle. “Cryptographic Apparatus and Method.” US Patent 4,200,770. April 1980. • Rivest, Ronald L. “The MD5 Message-Digest Algorithm”. RFC 1321. April 1992. • Maughan, Douglass, Mark Schetler, Mark Schneider, and Jeff Turner. Internet Security Association and Key Management Protocol (ISAKMP). (Internet-draft) draft-ietf-ipsec-isakmp08.txt, .ps. July 1997.

  15. PART 2 Multicast Routing using Mobile IP

  16. Multicast algorithms classification • Unicast dependent vs. Unicast independent • Source-Based vs. Shared Multicast Tree [Directly impact on Mobile IP] • Sparse mode vs. Dense mode Protocols: DVMRP, MOSPF, CBT, PIM(Dense/Sparse)

  17. Unicast dependent vs. Unicast independent Which one is better ? Multicast Multicast Unicast Unicast • Use property of specific • unicast routing algorithm • Deploy limitation • DVMRP(RIP) • MOSPF(OSPF) • Use general unicast function • Extra Multicast related state • Better interoperability • Protocol Independent Multicast

  18. Source2 (113.117.238.2) Source1(128.119.240.5) F A B D C E Receiver 1 Receiver 2 Source-Based vs. Shared Multicast Tree Source-Based Tree (DVMRP,MOSPF,PIM_Dense) • ? How to maintain LEAST UNICAST-COST PATH TREE • Multicast Open Shortest Path First • Distance Vector Multicast Routing Protocol

  19. Source A B C D E Receiver 1 Receiver 2 Receiver 3 Source-Based vs. Shared Multicast Tree Forwarding Packet with Source-Based Tree Reverse Path Forwarding Algorithm Transmit the packet on all of its outgoing links only if the packet arrived on the link that is on its own shortest path back to the source

  20. Source 1 Source 2 A B F D (Shared Root) C E Receiver 1 Receiver 2 Source-Based vs. Shared Multicast Tree Shared Tree (Core Base Tree, PIM_Sparse)

  21. Sparse mode Dense mode Pay Per View Radio Broadcast Few receiver Few non-receiver Join explicitly Join by default Broadcast prune,graft Shared/Source based tree Source based tree CBT, PIM_Sparse DVMRP, PIM_Dense Sparse mode vs. Dense mode

  22. Link Data Control Sparse Mode PIM Example Source A B D RP C E Receiver 1 Receiver 2

  23. Sparse Mode PIM Example Receiver 1 Joins Group GC Creates (*, G) State, Sends(*, G) Join to the RP Source A B D RP Join C E Receiver 1 Receiver 2

  24. Sparse Mode PIM Example RP Creates (*, G) State Source A B D RP C E Receiver 1 Receiver 2

  25. Sparse Mode PIM Example Source Sends DataA Sends Registers to the RP Source Register A B D RP C E Receiver 1 Receiver 2

  26. Sparse Mode PIM Example RP de-encapsulates RegistersForwards Data Down the Shared TreeSends Joins Towards the Source Source Join Join A B D RP C E Receiver 1 Receiver 2

  27. Sparse Mode PIM Example RP Sends Register-Stop OnceData Arrives Natively Source Register-Stop A B D RP C E Receiver 1 Receiver 2

  28. Sparse Mode PIM Example C Sends (S, G) Joins to Join theShortest Path (SPT) Tree Source A B D RP (S, G) Join C E Receiver 1 Receiver 2

  29. Sparse Mode PIM Example When C Receives Data Natively,It Sends Prunes Up the RP tree forthe Source. RP Deletes (S, G) OIF andSends Prune Towards the Source Source (S, G) Prune A B D RP (S, G) RP Bit Prune C E Receiver 1 Receiver 2

  30. Sparse Mode PIM Example New Receiver 2 JoinsE Creates State and Sends (*, G) Join Source A B D RP (*, G) Join C E Receiver 1 Receiver 2

  31. Sparse Mode PIM Example C Adds Link Towards E to the OIFList of Both (*, G) and (S, G)Data from Source Arrives at E Source A B D RP C E Receiver 1 Receiver 2

  32. Sparse Mode PIM Example New Source Starts SendingD Sends Registers, RP Sends JoinsRP Forwards Data to Receiversthrough Shared Tree Source Register Source 2 A B D RP C E Receiver 1 Receiver 2

  33. Link Data Control A B G C D F H E I Dense Mode PIM Example Source Receiver 1 Receiver 2

  34. A B G C D F H E I Dense Mode PIM Example Source Initial Flood of Dataand Creation of State Receiver 1 Receiver 2

  35. A B G C D F H E I Dense Mode PIM Example Source Prune to Non-RPF Neighbor Prune Receiver 1 Receiver 2

  36. A B G C D F H E I Dense Mode PIM Example Source C and D Assert to DetermineForwarder for the LAN, C Wins Asserts Receiver 1 Receiver 2

  37. A B G C D F H E I Dense Mode PIM Example Source I Gets Pruned E’s Prune is Ignored G’s Prune is Overridden Prune Join Override Prune Receiver 1 Receiver 2

  38. A B G C D F H E I Dense Mode PIM Example Source New Receiver, I Sends Graft Graft Receiver 1 Receiver 2 Receiver 3

  39. A B G C D F H E I Dense Mode PIM Example Source Receiver 1 Receiver 2 Receiver 3

  40. Multicast + Mobile IP • Mobile Host as Sender • Using Home Address as packet source address • Using Care-of Address as packet source address • Mobile Host as Receiver • Home Subscription Join multicast group using Home Address • Remote Subscription Join multicast group using Care-of Address

  41. Home Address as packet source address • Option 1: Packet directly sent out from foreign network • For Source-Based Tree (routing related to packet source address) Packet might not be delivered • For Central Based Tree (routing uncorrelated to packet source address) Packet will be delivered correctly • Option 2: Packet tunneled to Home Agent, then sent out Packet will be delivered correctly

  42. Care-of Address as packet source address • Packet directly sent out from foreign network Packet will be delivered correctly • Problem: How the misdelivered response reach the roaming sender ?

  43. Home Subscription • Packet first received at Home Agent, then forward to the mobile host. • Problem: Tunnel Convergence problem Source Home Agent (A) Home Agent (B) Foreign Agent Mobile Host (A) Mobile Host (B)

  44. Source Home Agent (A) Designated Multicast Service Provider Home Agent (B) Foreign Agent Home Subscription • Packet first received at Home Agent, then forward to the mobile host. • Problem: Tunnel Convergence problem Mobile Host (A) Mobile Host (B)

  45. Remote Subscription • It works fine since multicast packet is delivered based on multicast group address • Foreign network router should support multicast

  46. Conclusion • Mobile Host as Sender • Using Home Address as packet source address • Core Based Tree/ Tunneled packet sent out from Home Agent • Using Care-of Address as packet source address • Hardly to use • Mobile Host as Receiver • Home Subscription • Tunnel convergence problem • Remote Subscription • Foreign network support multicast

  47. References • Mobile Multicast(MoM) Protocol: Multicast Support for Mobile Hosts. Tim G. Harrison, Carey L. Williason, Wayne L. Mackrell, Richard B. Bunt. U. of Saskatchewan, Saskatoon, Canadan.Proceedings of the third annual ACM/IEEE international conference on Mobile computing and networking. September 26 - 30, 1997, Budapest Hungary • RelM: Reliable Multicast for Mobile Networks.Journal of Computer Communications, 1997.Kevin Brown, Suresh Singh • Supporting IP Multicast for Mobile Hosts, for review.Yu Wang, Weidong Chen.Southern Methodist University • Flexible Network Support for Mobile Hosts. X. Zhao, C. Castelluccia, M. Baker. Proc. MOBICOM '98, Dallas, Texas, 1998, pp. 145--156 • IP Multicast Extensions for Mobile Internetworking. In Proceedings of IEEE Infocom'96, March 1996 • IP Multicasting for wireless mobile hosts. George Xylomenos and George C. Polyzos. Proceedings of the IEEE MILCOM, 10 1996

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