Uli Bornhauser - Peter Martini - Martin Horneffer Scalability of ibgp Path Diversity Concepts

Transcription

1 Uli Bornhauser - Peter Martini - Martin Horneffer Scalability of ibgp Path Diversity Concepts p. 1 Scalability of ibgp Path Diversity Concepts - Computer Science 4, University of Bonn - Networking 2011

2 Introduction - ibgp Path Diversity ibgp Path Diversity Schemes Scalability Prediction Structure of the talk 2

3 Introduction - ibgp Path Diversity Scalability of ibgp Path Diversity Concepts p. 3 Scalability of ibgp Path Diversity Concepts - Computer Science 4, University of Bonn - Networking 2011

4 AS x only the best path is announced v u Classical ibgp p. 4 Scalability of ibgp Path Diversity Concepts - Computer Science 4, University of Bonn - Networking 2011

5 x v AS x only the best path is announced u old path is withdrawn, new path is announced convergence problems churn correctness problems Classical ibgp p. 5 Scalability of ibgp Path Diversity Concepts - Computer Science 4, University of Bonn - Networking 2011 no load sharing

6 AS x v u Add-path: simply announce several paths per prefix ibgp using Add-path 6

7 ibgp Path Diversity Schemes Scalability of ibgp Path Diversity Concepts p. 7 Scalability of ibgp Path Diversity Concepts - Computer Science 4, University of Bonn - Networking 2011

8 AS-wide best paths path with best local preference n best paths all known paths optimal path and local group bests AS-wide best paths and best next paths n best paths for each peer-as groups paths that remain after n steps ibgp path diversity schemes 8

9 AS-wide best paths path with best local preference n best paths all known paths optimal path and local group bests AS-wide best paths and best next paths n best paths for each peer-as groups paths that remain after n steps Schemes covered by our analysis 9

10 p1 p 2 p 3 p4 p3 p1 p 2 v reflector p1 p2 p3 all known paths best path per peer-as group cost-optimal path p3 p1 v reflector cost-optimal path and best path for local peer-as group Schemes discussed today 10

11 Scalability Prediction Scalability of ibgp Path Diversity Concepts p. 11 Scalability of ibgp Path Diversity Concepts - Computer Science 4, University of Bonn - Networking 2011

12 m reflectors AS x v internal paths local paths external paths Find the formal details in the paper! How many paths has a router v to manage? p. 12 Scalability of ibgp Path Diversity Concepts - Computer Science 4, University of Bonn - Networking 2011

13 AS Structure - Backbone of a large ISP (in Germany) exclusive ibgp speakers (08/2009) ebgp speakers (08/2009) - m=2 reflector sessions at most clients Peering and Paths - One provider AS (08/2009) - Several big peer ASs (08/2009) - Peering with around 600 neighboring ASs (08/2009) - Global routing table: ~300,000 prefixes - Internal routing table: ~60,000 prefixes The reference system - AS

14 $%'" (&" )%" $(" '" &" %" $" *++,"-+../01." *,02/3+,"-+../01." "/67*" $" (" $$" $(" %$" %(" )$" )(" &$" &(" #$" #(" ($" %#" %!" $#" $!" #"!" B!"#$%&!&&,5.&%!"#$%&'!()!*&%*!+!,-,./%!01!*.(2%'(13&%45*%65*!%13(.%7879%0%:;<=;>;#=;?% Common ibgp 14

15 $%'" (&" )%" $(" '" &" %" $" High load due to many provider and peer sessions *++,"-+../01." *,02/3+,"-+../01." "/67*" 899"*:;<." Load is almost independent of the external peering $" (" $$" $(" %$" %(" )$" )(" &$" &(" #$" #(" ($"!"#$%&'!()!*&%*!+!,-,./%!01!*.(2%'(13&%45*%65*!%13(.%7879%0%:;<=;>;#=;?% %#" %!" $#" $!" #"!" B!"#$%&!&&,5.&% Announcement of all paths 15

16 $%'" (&" )%" $(" '" &" %" $" *++,"-+../01." *,02/3+,"-+../01." "/67*" $" (" $$" $(" %$" %(" )$" )(" &$" &(" #$" #(" ($" %#" %!" $#" $!" #"!" B!"#$%&!&&,5.&%!"#$%&'!()!*&%*!+!,-,./%!01!*.(2%'(13&%45*%65*!%13(.%7879%0%:;<=;>;#=;?% Announcement of optimal + best paths for local peer-ass 16

17 $%'" (&" )%" $(" '" &" %" $" *++,"-+../01." *,02/3+,"-+../01." "/67*" 7,0E9." %"6+.>"*;>?." %"6+.>"*;>?."9+,"*++,CD-"7,0E9" D<<"*;>?." $" (" $$" $(" %$" %(" )$" )(" &$" &(" #$" #(" ($" %#" %!" $#" $!" #"!" B!"#$%&!&&,5.&%!"#$%&'!()!*&%*!+!,-,./%!01!*.(2%'(13&%45*%65*!%13(.%7879%0%:;<=;>;#=;?% Comparison of all schemes 17

18 Conclusion Scalability of ibgp Path Diversity Concepts p. 18 Scalability of ibgp Path Diversity Concepts - Computer Science 4, University of Bonn - Networking 2011

19 Path Diversity is an important aspect for the future of ibgp. Scalability predictions can be performed efficiently. Especially simple schemes may cause a significant load growth. Models and analyses of other schemes seem reasonable. Takeaways and future work 19

20 Questions? p. 20 Scalability of ibgp Path Diversity Concepts - Computer Science 4, University of Bonn - Networking 2011