Leverage through compe99on beler performance by

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: tes from F to H E’s Forwarding Choices F G E 3 10 3 1 4 A 4 Flow 2 4 B H D 2 1 2 3 C F à༎ H F à༎ C E à༎ H E à༎ C Possible Example next hops choice C, D D C, D D C, D C C, D C Use both paths to get to one des9na9on 74 23 10/29/13 Introduc9on to Computer Networks IP Prefix Aggrega9on and Subnets (§5.6.2) Computer Science & Engineering Introduc9on to Computer Networks Rou9ng with Policy (BGP) (§5.6.7) Computer Science & Engineering 24 10/29/13 Outline •  Interdomain rou9ng –  Autonomous Systems (ASes) •  Path- vector rou9ng –  Flexible path selec9on •  Business rela9onships –  Customer- provider and peer- peer –  Hierarchy from 9er- 1 ASes to stubs •  Border Gateway Protocol (BGP) –  Announcements and withdrawals –  Import and export policies Interdomain Rou9ng: Between Networks •  AS- level topology –  Nodes are Autonomous Systems (ASes) –  Des9na9ons are prefixes (e.g., 12.0.0.0/8) –  Edges are links and business rela9onships 4 3 5 2 1 Client 7 6 Web server 25 10/29/13 AS Numbers (ASNs) ASNs are 16 bit values. Currently around 30,000 in use. •  •  •  •  •  •  Level 3: 1 Harvard: 11 AT&T: 7018, 6341, 5074, … UUNET: 701, 702, 284, 12199, … Sprint: 1239, 1240, 6211, 6242, … … ASNs represent units of routing policy Challenges for Interdomain Rou9ng •  Scale –  Prefixes: 250,000, and growing –  ASes: 30,000, and growing •  Privacy –  ASes don’t want to divulge internal topologies –  … or their business rela9onships with neighbors •  Policy –  Need control over where you send traffic –  … and who can send traffic through you 26 10/29/13 Policy- Based Path- Vector Rou9ng Path- Vector Rou9ng •  Extension of dis...
View Full Document

This document was uploaded on 04/04/2014.

Ask a homework question - tutors are online