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AS-level Multi-Path Routing

Presenter:

Adriana SzekeresVrije Universiteit Amsterdam/NLnet Labs

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Contents

• Introduction to AS-level multi-path routing• Motivation of our work• Our work

– Short presentation– The experiments we conduct

• Preliminary results

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Introduction

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Introduction

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Introduction

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IntroductionProblem: Disconnectivity during BGP’s convergence

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Introduction

• AS-level Multi-Path Routing idea:– supply multiple paths– find the most disjoint paths from the one

currently used (to cover a wide area of failures).

AS-level Multi-Path Routing: nice to have, but it may come at some costs.

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Motivation

• Number of ASes – almost doubled from 2004– BGP faces scalability and stability problems

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Motivation

• Number of ASes – almost doubled from 2004– BGP faces scalability and stability problems– Reticence to new BGP enhancements

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Motivation

• Number of ASes – almost doubled from 2004– BGP faces scalability and stability problems– Reticence to new BGP enhancements

Every new BGP addition should be carefullystudied and tested

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Our work

• Study the promises of the recently proposed AS-level multi-path routing methods (2009)– Resilient_BGP

• each AS advertise a fail-over path to the AS through which it is routing

– Multi-Process_BGP• run multiple BGP instances that advertise disjoint

paths

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Experiments

• Show:– impact on BGP’s scalability– the degree of fault tolerance

• BGPsim simulator– can simulate more than 30.000 ASes– ran on DAS-4 cluster; using 33 nodes; 8

cores/node– CAIDA topologies from 2005 to 2010

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Preliminary results

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Preliminary results2005

maximum node disjointness

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Preliminary results2009

maximum node disjointness

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Conclusion

• Importance:– BGP protocol designers and network

operators:• impact on scalability• efficiency

• Future work– further analyze the routing tables– more methods