USC CSCI 551 - 07b_bgpops (22 pages)

Previewing pages 1, 2, 21, 22 of 22 page document View the full content.
View Full Document

07b_bgpops



Previewing pages 1, 2, 21, 22 of actual document.

View the full content.
View Full Document
View Full Document

07b_bgpops

92 views


Pages:
22
School:
University of Southern California
Course:
Csci 551 - Computer Communications

Unformatted text preview:

Computer Communications CSCI 551 CS551 Multi homing in BGP Bill Cheng http merlot usc edu cs551 f12 1 Copyright William C Cheng Computer Communications CSCI 551 Transit vs Nontransit Services ISP1 singly homed subscriber ISP3 ISP2 Customer1 Customer3 Customer2 ISPn provides transit service to Customern ISPn provides non transit service from another ISP for traffic for its customer 2 Copyright William C Cheng Computer Communications CSCI 551 Multi homing With multi homing a single network has more than one connections to the Internet Improves reliability and performance can accommodate link failure bandwidth is sum of links to Internet Multiple connections provide load sharing but not load balancing BGP cannot do load balancing 3 Copyright William C Cheng Computer Communications CSCI 551 Issues With Multi homing Symmetric routing while conventional wisdom prefers symmetric paths many are asymmetric Packet re ordering may trigger TCP s fast retransmit algorithm Other concerns addressing DNS aggregation Note using BGP in multi homing situation is not an off the shelf use of the protocol 4 Copyright William C Cheng Computer Communications CSCI 551 Static Routing May Not Work ISP2 ISP3 Interconnect traffic for ISP2 n ISPn Customer traffic for ISP1 ISP1 R2 R3 R1 Static routing may send traffic to ISPs 2 n from customer over one link and traffic to ISP1 over the other link Lacks flexibility especially when ISP1 grows and shrink 5 Copyright William C Cheng Computer Communications CSCI 551 Multi homing to a Single Provider Case 1 Easy solution no BGP but use IMUX or Multilink PPP Harder solution use BGP makes assumptions about traffic same amount of prefixes can be reached from both links ISP R1 R2 Customer 6 Copyright William C Cheng Computer Communications CSCI 551 Multi homing to a Single Provider Case 2 For ISP Customer traffic use MED in Customer or LOCAL PREF in ISP For Customer ISP traffic break down prefix and advertise different prefixes over different links with



View Full Document

Access the best Study Guides, Lecture Notes and Practice Exams

Loading Unlocking...
Login

Join to view 07b_bgpops and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view 07b_bgpops and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?