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Routing in Mobile Networks

Routing in Mobile Networks. Professor Ching-Chi Hsu Part I. Mobile IP on Network Layer Part II. Routing in Mobile/Wireless Ad-hoc Networks. Mobile IP on Network Layer. DNS based Name to Address resolution Network Layer Mobility Problem Illustration of Terms in Mobile IP

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Routing in Mobile Networks

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  1. Routing in Mobile Networks Professor Ching-Chi Hsu Part I. Mobile IP on Network Layer Part II. Routing in Mobile/Wireless Ad-hoc Networks

  2. Mobile IP on Network Layer • DNS based Name to Address resolution • Network Layer Mobility Problem • Illustration of Terms in Mobile IP • Two Tier Addressing • Mobile IP Architecture Components • Address Translation Mechanisms • Mobile IP Proposals

  3. DNS based Name to Address resolution

  4. Network Layer Mobility ProblemDirectory Service View • DNS didn’t handle dynamic updates. • DNS design attempts to optimize the access cost, and not the update cost. • There is no call back mechanism generally available from servers to clients in case the cached entries of the DNS clients become invalid.

  5. Network Layer Mobility Problem Internet View TCP connection: <source IP address, source TCP port, destination IP address, destination TCP port> • If the mobile host acquires a new IP address, all TCP connections involving the mobile host will be broken. • If the mobile host retains its address, then the routing system cannot forward packets to its new locations.

  6. Illustration of Terms in Mobile IP

  7. Two Tier Addressing

  8. Mobile IP Architecture Components

  9. Address Translation MechanismsEncapsulation

  10. Address Translation MechanismsLoose Source Routing

  11. Mobile IP ProposalsColumbia Scheme

  12. Mobile IP ProposalsSony Scheme

  13. Mobile IP ProposalsLSR Scheme

  14. Mobile IP ProposalsIETF Scheme

  15. Routing in Mobile/Wireless Ad-Hoc Networks • Introduction • Definitions of Dynamic Groups Routing • Dynamic Groups Routing Algorithms • Simulation and Analysis • Conclusion • Future Works

  16. Introduction • Ad-Hoc Networks Model • Previous Works on Routing in Ad-Hoc Networks • Motivations of Dynamic Groups Routing

  17. Ad-Hoc Networks Model • Ad-hoc networks • Wireless communication • Without fixed network interaction and centralized administration. • Multi-hop routing style with no cheating of the forwarding nodes mobile host routing

  18. Ad-Hoc Networks Model • Why ad-hoc networks ? • When the access base station are not set up due to low cost effect, poor performance or low usage • Ad-hoc networks may be the extension of base stations • Applications of ad-hoc networks • An outdoor conference • Emergency situations of natural disasters • Military deploys in battlefield Bridges Ad-hoc networks Base station

  19. Previous Works on Routing in Ad-Hoc Networks • On-demand dynamic source routing (D.B.Johnson et al.) • Cluster-based routing (P. Krishna et al.) • Zone routing (Z.J. Haas et al.) • Minimum connected dominating set routing (B. Das et al.)

  20. On-demand dynamic source routing • Loosely source routing while route requested • Each node may overhear the routing information from the neighbor nodes. • Example: source routing and overhearing source destination Route request message Route reply message Mobile node Overhearing range

  21. Cluster-based routing • The clustering method depends on the k-hop mutually reachable relation between any two nodes in a cluster. • A two-level network graph - cluster-level + node-level • Example: 1-cluster(fully connected sub-graphs as clusters) Mobile node Cluster

  22. Zone routing • Zone - the nodes within the defined radius • Radius - hop-count reachable from the central node • Each node maintain the topology in its zone • Example: zone with radius = 2 Mobile node Zone

  23. Minimum connected dominating set routing • Minimum connected dominating set (MCDS) - construct a so-called virtual backbone in an ad-hoc network. • Routing through the virtual backbone by dominators. • Example: virtual backbone construction MCDS edge Non-MCDS edge Mobile node dominators MCDS(virtual backbone)

  24. Comparison Routing methods Infrastructure Advantages Disadvantages Only sense the neighbors Less overhead to maintain topology Frequent routing make it mass route discovery overhead On-demand Routing Uniform cluster with the node as the center Easy to maintain the topology in zones Frequent moving causing heavy topology update Zone Routing (cluster-based) Network grown up make the virtual backbone a heavy burden MCDS virtual backbone as routing trunk Simple to search routes by virtual backbone MCDS Routing

  25. Motivations of Dynamic Groups Routing • Ad-hoc network topology maintenance • Range Consideration • The whole network - inefficient and infeasible. • Only neighbors - inefficient while frequent route requesting • Structure Consideration • Relative conectivity • Relative position • To propose an easy topology maintenance and good traffic isolation ad-hoc network routing system- Dynamic Groups Routing

  26. Definitions of Dynamic Groups Routing • Illustration of an ad-hoc network construction • Definitions • Dominating value definition • Routing groups definitions • Definitions of attachable sets, bridge and peripheral clusters

  27. Illustration of an ad-hoc network construction P A B M Q C D H N O R E I K F G J L Positive cluster Non-positive cluster Routing group

  28. Dominating value definition • Definition 1: DV(p) is the dominating value of a node p in an ad-hoc network. It is calculated as the following before the construction proceeds. Initial DV(p) := 0 For each q which q in neighborhood of p If deg(p) > deg(q) then DV(p) := DV(p) +1 else if deg(p) < deg(q) DV(p) := DV(p) – 1 • Theorem 1: In the initial constructed bi-directional connected network, the summation of all dominating values of nodes is zero.

  29. Routing groupsdefinitions • Definition 2: A node p is positive while DV(p) > 0, otherwise non-positive. • Definition 3:In a constructed ad-hoc network, the cluster formed by all connected positive nodes is called positive cluster (P-cluster). The cluster formed by all connected non-positive nodes is called non-positive cluster (N-cluster). • Definition 4:A routing group (RG) is formed by one P-cluster with its adjacent N-clusters

  30. Definitions of attachable sets,bridge and peripheral clusters • Definition 4: An attachable set is a set of all the positive nodes in the same P-cluster with direct bi-directional links to the same adjacent N-cluster • Definition 5:A bridge cluster is the N-cluster belonged to more than one RG. On the other hand, the N-cluster belonged to one RG is called peripheral cluster.

  31. Dynamic Groups Routing Algorithms • Construction algorithm • Route discovery strategy • Route maintenance • Connection recovery

  32. Message propagating illustration in construction <3,-2> <2,-2> <3,0> P <2,-2> Nlist(A),DV(A) A B M <4,4> <3,0> <5,+2> Q <2,0> C D H N O <5,+2> <3,-2> <5,+2> <5,+2> R <2,-2> E I K <2,-1> Note: <degree, DV> F G J L <2,0> <2,-1> <2,-1> <2,-1>

  33. Construction algorithm {For each mobile node p in the ad-hoc network} Broadcast message deg(p) to all neighbors Receive message deg(q) from each neighbor q Calculate DV(p) as definition 1 Broadcast message {List(N(p)) ,DV(p)} to each neighbor q Receive message {List(N(r)) ,DV(r)} from each neighbor q For each message {List(N(r)) ,DV(r)} Case 1. DV(p) > 0 & DV(q) > 0 Propagate it to all positive neighbors excluding q Case 2. DV(p) > 0 & DV(q) <= 0 Propagate it to all positive neighbors Case 3. DV(p) <= 0 & DV(q) <= 0 Propagate to all neighbors excluding q Case 4. DV(p) <= 0 & DV(q) > 0 Ignore the message

  34. Route discovery illustration Intra-cluster Intra-group Inter-group Intra-group Inter-group Intra-cluster Mobile node S RG P-cluster N-cluster

  35. Route discovery strategy For a route request from the source node s to the destination node d if(the node s is non-positive) then it checks the local topology information of its N-cluster if (the destination node d is found) then it routes from the node s to the node d directly else it multicasts intra-group route request message to all thenodes in its attachable sets and waits for reply message if (all the reply message are failure) then it issues inter-group route request message to all the nodes in its attachable sets else it routes by the reply information from one of the nodes in its attachable sets else it checks the local topology information of its routing group if (the destination node d is found) then it routes from the node s to the node d directly else it multicasts inter-group route request message to all the nodes in the attachable sets of all its bridge clusters,which also belong to other routing groups

  36. Route maintenance(link variations) • 6 kinds of reactions to the variations Reacting/Interacting node Interacting/Reacting node Link Hm Hn Connected/Disconnected N/P N/P 2 * 2 * 2 = 8

  37. Route maintenance(link variations)

  38. Route maintenance(connectivity dominating variations) DV(E): +2 -1 G A D E F H B I C

  39. Route maintenance(connectivity dominating variations)

  40. Route maintenance(connectivity dominating variations)

  41. Connection Recovery • Group-level backtracking to the last one New route N-cluster N-cluster N-cluster P-cluster P-cluster RG1 RG2

  42. Connection Recovery

  43. Simulations and Analysis • Simulation model • Simulation results

  44. Simulation model • N mobile nodes move randomly in a square area

  45. Simulation results • Connectionless • Variant number of mobile hosts • Variant moving frequency of mobile hosts • Variant route query frequency of mobile hosts • Connection-oriented • 32 mobile hosts in 800m*800m area • 72 mobile hosts in 1200m*1200m area

  46. Total delay in route maintenance phase by increasing number of mobile hosts

  47. Control traffic in route maintenance phaseby increasing number of mobile hosts

  48. Control traffic in route discovery phase byincreasing number of mobile hosts

  49. Total control traffic by increasing number of mobile hosts

  50. Total delay in route maintenance phase by increasing moving frequency

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