### Information

 Author(s) Olivier Bonaventure Deadline No deadline Submission limit No limitation Category tags BGP

## Interdomain routing policies - Another influence of peering link type (prefix from AS2 seen by AS4)

Consider the simple interdomain network shown below where we will look at the impact of the routing policies on the link between AS2 and AS4 on the paths towards the prefix advertised by AS2 that are received by AS4

Provide your answers as a comma-separated list of paths starting with the preferred one. For example, the answer:

AS9:AS1, AS8:AS7:AS1


indicates that the AS has learned two different paths. The preferred one is the one via AS9 that has a length of 2 AS hops while the second path has a length of 3 AS hops. If there is no path, return 0 as your answer.

##### Question 1: Interdomain paths

What are the interdomain paths that AS4 has learned to reach the prefix advertised by AS2 in the network below if AS2 is a shared cost peer of AS4?

##### Question 2: Interdomain paths

What are the interdomain paths that AS4 has learned to reach the prefix advertised by AS2 in the network above if AS2 is a customer of AS4?

##### Question 3: Interdomain paths

What are the interdomain paths that AS4 has learned to reach the prefix advertised by AS2 in the network above if AS2 is a provider peer of AS4?