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Routing Algorithm

www.btechebooks4u.blogspot.com. Routing Algorithm. Your Text Here. 2004. 11. 3 Ahn Kook Jin. www.btechebooks4u.blogspot.com. Contents. Routing Protocol and Algorithm Classifications Link State Routing Algorithm Distance Vector Routing Algorithm LS Algorithm vs. DV Algorithm

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Routing Algorithm

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  1. www.btechebooks4u.blogspot.com Routing Algorithm Your Text Here 2004. 11. 3 Ahn Kook Jin

  2. www.btechebooks4u.blogspot.com Contents • Routing Protocol and Algorithm • Classifications • Link State Routing Algorithm • Distance Vector Routing Algorithm • LS Algorithm vs. DV Algorithm • Hierarchical Routing

  3. destination router 5 first-hop routerdefault router 3 B D 2 5 2 3 1 F A 1 1 2 C E least-cost path source router Routing Protocol and Algorithm • Determining the path(route) destination host source host www.btechebooks4u.blogspot.com

  4. www.btechebooks4u.blogspot.com Classifications • Global vs. decentralized • global(link state algorithm) : complete information about connectivity and link costs • Static vs. dynamic • static : routes change very slowly • Load-sensitive vs. load-insensitive • load-sensitive : link costs reflect congestion • Typical used • Dynamic link state routing algorithm • Dynamic distance vector routing algorithm

  5. Link State Routing Algorithm • Each node broadcasts the identities and costs to its directly attached neighbors • Dijkstra’s algorithm www.btechebooks4u.blogspot.com

  6. 1 2+e 0 2+e 0 0 0 0 0 0 0 0 0 2+e 0 1+e A C B D 1 1 1+e 0 0 1+e 1 1 0 0 0 0 1 0 e 0 1+e 0 e Link State Routing Algorithm • Oscillation(page 307) www.btechebooks4u.blogspot.com

  7. Distance Vector Routing Algorithm • Iterative, asynchronous, distributed • Distance table • DX(Y,Z) : cost of the direct link from X to Z + Z’s currently known minmum-cost path to Y • DX(Y,Z)=c(X,Z)+minw{Dz(Y,w)} www.btechebooks4u.blogspot.com

  8. Distance Vector Routing Algorithm • Initialization: • DX(*,v) = inifinite, DX(v,v)=c(x,v) • Send minwDX(y,w) to each neighbor when they changes • C(X,V) changes • Neighbor node send its update www.btechebooks4u.blogspot.com

  9. Y X Z Distance Vector Routing Algorithm 2 1 7 www.btechebooks4u.blogspot.com

  10. Y X Z Distance Vector Routing Algorithm 2 1 7

  11. Y X Z Distance Vector Routing Algorithm 2 1 7

  12. Y X Z Distance Vector Routing Algorithm • Decrease 1 4 1 50

  13. Y X Z Distance Vector Routing Algorithm • Decrease 1 4 1 50

  14. Y X Z Distance Vector Routing Algorithm • Decrease 1 4 1 50

  15. Y X Z Distance Vector Routing Algorithm • Decrease 1 4 1 50

  16. Y X Z Distance Vector Routing Algorithm • Increase 60 4 1 50

  17. Y X Z Distance Vector Routing Algorithm • Increase 60 4 1 Routing loop 50

  18. Y X Z Distance Vector Routing Algorithm • Increase 60 4 1 50

  19. Y X Z Distance Vector Routing Algorithm • Increase 60 4 1 50

  20. Y X Z Distance Vector Routing Algorithm • Increase 60 4 1 Too many iterations! (count-to-infinity problem) 50

  21. Y X Z Distance Vector Routing Algorithm • Poisoned reverse 60 4 1 50

  22. Y X Z Distance Vector Routing Algorithm • Poisoned reverse 60 4 1 50

  23. Y X Z Distance Vector Routing Algorithm • Poisoned reverse 60 4 1 50

  24. Y X Z Distance Vector Routing Algorithm • Poisoned reverse 60 4 1 50

  25. Y X Z Distance Vector Routing Algorithm • Poisoned reverse • Cannot solve general count-to-infinity problem 60 4 1 50

  26. LS Algorithm vs. DV Algorithm

  27. Hierarchical Routing • View network as interconnected routers • Scale • Administrative autonomy • Organize routers into autonomy systems(AS)

  28. B.a C.a A.a B.a A.b A.d C.b C.c Host H1 A.c Host H2 Hierarchical Routing Autonomy system(AS)Gateway routerIntra-ASInter-AS

  29. B.a A.a A.c C.a Hierarchical Routing Topological view for inter-AS routing protocol

  30. END Download more ebooks @ www.btechebooks4u.blogspot.com

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