SHARE
SPREAD
HELP

The Tradition of Sharing

Help your friends and juniors by posting answers to the questions that you know. Also post questions that are not available.


To start with, Sr2Jr’s first step is to reduce the expenses related to education. To achieve this goal Sr2Jr organized the textbook’s question and answers. Sr2Jr is community based and need your support to fill the question and answers. The question and answers posted will be available free of cost to all.

 

#
Authors:
James F. Kurose, Keith W. Ross
Chapter:
The Network Layer
Exercise:
Problems
Question:43 | ISBN:9780132856201 | Edition: 6

Question

Suppose ASs X and Z are not directly connected but instead are connected by AS Y. Further suppose that X has a peering agreement with Y, and that Y has a peering agreement with Z. Finally, suppose that Z wants to transit all of Y’s traffic but does not want to transit X’s traffic. Does BGP allow Z to implement this policy?

TextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbookTextbook

Answer

Yes, BGP allows Z to implement the given policy.

Given data:

The network contains Autonomous Systems AS X, AS Y and AS Z.

BGP means  Border Gateway Protocol.  It is an Inter-AS routing protocol.

  • It takes the subnet reachability data from neighboring AS.
  • AS X has an agreement of peering with AS Y.
  • AS Y has an agreement of peering with AS Z.
  • This protocol permits AS Z to develop the policy.
  • The BGP route trailers are held by each AS.
  • AS Y should present AS X that, it has no path to Z.
  • The system AS X is ignorant that AS Y has path to AS Z.
  • AS X never forward the traffic.
  • AS Z can transfer all of Y’s traffic.
0 0

Discussions

Post the discussion to improve the above solution.