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Mobile IP, or TCP/IP on tour

Mobile IP, or TCP/IP on tour. Distribuerade system, VT2000 Jerry.Eriksson@cs.umu.se. Why Mobility? IP routing, very short The need for Mobile IP. Mobile IP - Overview The Gory Details Tunneling. Future: Mobility for IPV6 Open Issues TCP performance (RSVP and Real-Time Traffic)

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Mobile IP, or TCP/IP on tour

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  1. Mobile IP, or TCP/IP on tour Distribuerade system, VT2000 Jerry.Eriksson@cs.umu.se

  2. Why Mobility? IP routing, very short The need for Mobile IP. Mobile IP - Overview The Gory Details Tunneling Future: Mobility for IPV6 Open Issues TCP performance (RSVP and Real-Time Traffic) Service Location Summary and future for Mobile IP Outline

  3. Computers doesn’t stay put. Change location without restart its application or terminating any ongoing communication Example 1: Un-plug at campus, and plug it back at home Example 2: Un-plug from office, let the wireless network take over Mobile IP: A standard for mobile computing and networking

  4. Protocol layer Network Layer Transport Layer What does IP do moving packets from source to destination No ’end-to-end’ guarantees IP addresses Network-prefix Host portion IP Routing Packet Header Network-prefix Every node on the same link has the same network-prefix IP Networking

  5. Fig 3.1 host Specific Routes (too costly) Node’s IP address (TCP fails) Link layer (Too many standards) The Need for Mobile IP

  6. If a node moves from one link to another without chnging its IP address, it will be unable to receive packets at the new link; and If a node changes its IP address when it moves, it will have to terminate and restart any on-going communications each time it moves Mobile IP Solves the following problems

  7. Proposed as a Standard in November 1996 Solution for Internet Scalable, robust, secure, maintain communication Use their permanent IP address Routing protocol Route packets to nodes that could potentially change location very rapidly Layer 4-7, outside Mobile IP, but will be of major interest (TCP, for example) Mobile IP Overview

  8. Communicate wtih other nodes after changing its link-Layer attachment to the internet. Communicate using only its home IP address. Communicate with other computers not using Mobile IP. Handle security threats efficiently Reqiurements for Mobile IP; A node must be able to

  9. Size and and the frequency as small as possible Simple to implement. Aviod solutions that uses multilpe IP adresses (Running out of IPv4 adresses Design goals

  10. Mobile Node (mobilen) Home Agent (Hemagent) Foreign agent (fjärragent) Home link (hemmalänk) Foreign Link (fjärrlänk) care-of-addresses (c/o, besöksadress) 4.7: Mobile IP Entities and Relationships (Fig. 4-1)

  11. A router with an interface on the mobile node’ home link Node keep the Home agent informed of its current location (care-of-addresses) Advertises reachability to the network-prefix of the mobile node’s home adress (Attracting IP adresses) intercepts packets destined to the mobile node’s home adress and tunnels them to (c/o) Home agent

  12. Foreign Agent • A router on a mobile node’s foreign link which • assists the mobile node in informaing its home agent of its current (c/o) • provides (c/o) adress and de-tunnels packets (sent from the home agent) • default router generated by the mobile node.

  13. An encapsulating IP packet including a path and an original IP packet Figure 4-2 Tunneling

  14. Home Adress - IP adress permanently assigned to a mobile node (Does not change) Home Link - network-prefix of the mobile node’s home address define its home link Home agent - A router that has at least one interface on the mbile node’s home link Definitions on ’Home’

  15. A c/o is specific to the foreign link currently being visited by a mobile node. A node’s c/o changes every time the mobile node moves from one foreign link to another Packets desitnated to a c/o can be delivered using existing Internet routing mechanisms A c/o is used as an exit pont of a tunnel from the home agent toward the mobile node Definitions on c/o

  16. Home agents and foreign agents advertise their presence by periodically multicasting (broadcasting) Agent advertisements Mobile node’s listens to Agent advertisements (I am a home or away) A mobile node connected to a foreign link acquires a c/o adress Mobile node registers its c/o address with its home agent 4.8: A high Level desription (Fig. 4-3)

  17. Home agent adverties reachibility to the netwrok-prefix of the mobile node’s home link (Attracting packets sent to the mobiles home adress. Intercept these messages and tunnels them to the C/O At C/O, the original packet is extracted from the tunnel and then delivered to the mobile node In reverse odirection, packets sent from the mobile node are routed directly to thier destination, without need for tunneling (FA only router) 4.8: A high Level desription (Fig. 4-3) Cont:

  18. Agent Discovery Determines whether it is currently connected to its home link or a foreign link. Detects whether it has moved from one link to another obtains a care-of adress when connected to a foreign link 5: The gory details

  19. Agent advertisements; Used by agents to announce their capabilities to mobile nodes Agent advertisements are continuously transmitted (multicast/broadcoast) on a specific link Allow the mobiles to determine whether any agent is present (gets identities) Agent solicitations; are sent by mobile that do not have the patience to wait for an Agent advertisment 5.2.1: Messages

  20. Using Lifetime: Tells the mobile how soon it should expect to hear another Agent Advertisment. AA three times faster than Lifetime Multiple foreign agents 5.2.2 How does a mobile node detrmine that is has moved?

  21. A mobile node register whenever it detects that it has chnged link from one network to another. Reregisters when it has not moved, but when it existing registration due to expire. Mobile IP registration is the process by which a mobile node: requests routing services from a foreign agent or foreign link informs its home agent of its current care-of-address. Renews a registration due to expire deregisters when it returns to its home link 5.3 What is registration

  22. A registration consists of an exchange of a Registration request and a Registration Reply between a mobile node and its home agent. Three common scenarios: Using foreign agent c/o Using collocated c/o deregisters upon returning home 5.3.1 Registration scenarios

  23. Se summary 5.3.2 How do nodes Process registrations

  24. 5.3.3 How can a Mobile learn

  25. 5.3.4. How Does

  26. 5.4: How are the Packets routed

  27. 5.4.6 Why the triangle routing

  28. Agent Discovery Registration Routing 5.5 Summary

  29. Tunneling: 6.1 IP Encapsulation

  30. Size adresses: 128 bits vs 32 bits No real chance of running out of adresses A single newtowrk-prefix route Autoconfigure using very simple mechanisms Less frequently used fields in IPv4 moved into optional IPv6 more rigorously defined (more useful) Future Topics; Work in progress 12: IPv6 vs IPv4

  31. Larger adresses - No need for Foreign agents Collocated C/O is the only one needed, snice there are sufficient IP adresses New routing Header help Security attack (less options) Very fast forward desicion- not all routers need to read by every router, Router Discovery Static Address Autoconfiguration - 12.2 Relevant to Mobile IP V6

  32. Base: Priority fields, Flow label (Real-time traffic) Extension headers: Form a chain of headers 12.1.1 Headers

  33. 12.4 How Does it work

  34. 12.5 How does a Mobile ...

  35. 12.6 How Does

  36. 12.8: IP V6 summary

  37. 13: Open Issues. 13.1: TCP Performance and Mobility

  38. 13.1.1: What is TCP

  39. 13.1.2: How does TCP works

  40. 13.1.3: Are TCP’s ..

  41. 13.1.4: How can TCP

  42. 13.2 RSVP and Real-Time Traffic

  43. 13.3 Service Location

  44. Background Terminology Applying Mobile IP Open Issues 14: Summary

  45. 14: The future of Mobile IP

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