300-320 · Question #313
Which two BGP attributes can be set with outbound policy to manipulate inbound traffic, if honored by the remote Autonomous system? (Choose two)
The correct answer is A. Multi-exit discriminator (MED) B. AS path. To influence how a remote AS sends traffic INTO your AS (inbound traffic), you must set attributes on routes you ADVERTISE outbound that the remote AS will then evaluate. MED (Multi-Exit Discriminator) is sent to a neighboring AS to suggest a preferred entry point when multiple…
Question
Which two BGP attributes can be set with outbound policy to manipulate inbound traffic, if honored by the remote Autonomous system? (Choose two)
Options
- AMulti-exit discriminator (MED)
- BAS path
- CLocal Preference
- DWeight
How the community answered
(29 responses)- A72% (21)
- C17% (5)
- D10% (3)
Explanation
To influence how a remote AS sends traffic INTO your AS (inbound traffic), you must set attributes on routes you ADVERTISE outbound that the remote AS will then evaluate. MED (Multi-Exit Discriminator) is sent to a neighboring AS to suggest a preferred entry point when multiple links exist between the two ASes - a lower MED is preferred. AS Path prepending artificially lengthens your AS path in outbound advertisements, making that path appear less attractive to the remote AS and steering inbound traffic to a different link. Local Preference (choice C) is used to influence outbound traffic within a single AS and is not exchanged between ASes (it is non-transitive). Weight (choice D) is Cisco-proprietary, local to a single router, and never advertised to any peer - it only affects outbound path selection on that one router.
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