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Sensibility analysis of BGP convergence and scalability using network simulation

Sensibility analysis of BGP convergence and scalability using network simulation. Wolfgang Mühlbauer 5. Oktober 2004. Outline. Running the experiments Influence of MRAI timer settings on convergence times number of updates Propagation of updates number of affected ASes

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Sensibility analysis of BGP convergence and scalability using network simulation

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  1. Sensibility analysis of BGP convergence and scalability using network simulation Wolfgang Mühlbauer 5. Oktober 2004 SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  2. Outline • Running the experiments • Influence of MRAI timer settings on • convergence times • number of updates • Propagation of updates • number of affected ASes • propagation radius SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  3. Experiments - SSFNet • Network simulation with SSFNet • global view • existing BGP implementation • Modifications to SSFNet • Modeling the behavior of Cisco routers • Normal distribution of MRAI timer value • Community values • Best Path Selection Process, … • Configuring link failures • MRAI timer basis: per-peer or per-prefix, … SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  4. Experiments – Doing simulation • AS Pairs: define topology, reflect commercial relationships (e.g. 12>13) • Subtree extraction: reduce complexity and size of sample networks • DML Files: configuration files, input for SSFNet AS Pairs Subtree (AS Pairs) DML Files SimulationSSFNet SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  5. Experiments – DML Files • Topology Converter: Automatical generation of DML files out of AS Pairs • Configurable BGP parameters: • MRAI timer • Link failure dynamics • Interior structure of ASes (route reflectors, …) • WRATE, SSLD • … SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  6. Experiments – Sample topologies Middle Topology SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  7. Outline • Running the experiments • Influence of MRAI timer settings on • convergence times • number of updates • Propagation of updates • number of affected Ases • propagation radius SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  8. MRAI – How it works AS 2 AS 1 AS 5 AS 3 AS 4 SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  9. MRAI – How it works AS 2 AS 1 AS 5 AS 3 AS 4 AS 1 issues an update to AS 2 and AS 3 SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  10. MRAI – How it works AS 2 AS 1 AS 5 AS 3 AS 4 AS 2 "passes on" the information to AS 4 SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  11. timer instance is started MRAI – How it works AS 2 AS 1 AS 5 AS 3 AS 4 AS 4 "passes on" the information to AS 5 SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  12. MRAI – How it works AS 2 AS 1 AS 5 AS 3 AS 4 AS 3 sends its update to AS 4 not until now! SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  13. MRAI – How it works AS 2 AS 1 ? AS 5 timer is not expired yet AS 3 AS 4 AS 4 may prefer to reach AS 1 via AS 3, but … SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  14. MRAI – How it works AS 2 AS 1 AS 5 timer expires AS 3 AS 4 update is sent, now AS 4 can reach AS 1 via AS 3 SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  15. different link failures (5) MRAI timer values in sec (4,5,10,...,60) different seeds (20) simulation MRAI – Simulations • Automatical testing of 3 dimensions: • For Topology 7774 measure: • Convergence time • Number of external updates SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  16. MRAI – Results SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  17. 0.0.0.1/26 0.0.0.2/26 MRAI – per prefix or per peer per peer per prefix SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  18. MRAI – per prefix or per peer • used topologies: • Topology 1140 • Topology 7774 • testing of 4 dimensions • 5 different failure scenarios • different MRAI timer values (4s, 5s, 10s, …, 60s) • per-peer and per-prefix timer basis • 3 different seeds for random number generator • we measure • convergence times • number of external updates SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  19. MRAI – per-prefix vs per-peer SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  20. Outline • Running the experiments • Influence of MRAI timer settings on • convergence times • number of updates • Propagation of updates • number of affected Ases • propagation radius SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  21. Propagation – Update Radius radius 0 radius 0 SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  22. Propagation – Update Radius radius 1 radius 1 radius 1 radius 1 radius 1 SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  23. Propagation – Update Radius radius 2 radius 2 SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  24. Propagation – Affected ASes 1) US to D 2) D to US US providers use link 1 for German destinations German providers use link 2 for US destinations SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  25. Propagation – Affected ASes 1) US to D 2) D to US Link 1 fails due to some reason SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  26. Propagation – Affected ASes 2) D to US US to D Even traffic from US to D is now routed over link 2 But: Routers in D won‘t get an update message and are therefore not „affected“ SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  27. Propagation – Link Classification • classify ASes according to their commercial relationships: • tier1 ASes: no provider • stub ASes: no customer • middle Ases: all the rest • classify external links according to the ASes they connect: tier1-tier1, tier1-middle, middle-middle, middle-stub, stub-stub • Harmfulness of links reflected? SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  28. Propagation - Simulations • used topologies: • Topology Middle • Topology 1140 • Topology 7774 • testing of 3 dimensions • 10 different failure scenarios • different link categories • 3 different seeds for random number generator • we measure • number and ratio of affected ASes • mean and maximum of propagation radius SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  29. Propagation – Affected ASes SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  30. Propagation – Affected ASes Topology 7774 SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  31. Propagation - Radius SEP: Sensibility analysis of BGP convergence and scalability using network simulation

  32. Danke fürs Zuhören! Email: muehlbaw@in.tum.de SEP: Sensibility analysis of BGP convergence and scalability using network simulation

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