An engineer is designing a redundant dual-homed BGP solution that should prefer one specific carrier under normal conditions. Traffic should automatically fail over to a secondary carrier in case of…

The correct answer is A. AS-PATH E. MED. Inbound traffic is controlled by attributes that influence how external neighbors choose their exit path toward your AS. AS-PATH prepending (A) makes your AS appear farther away on one link, causing the remote carrier to prefer the shorter path - the primary carrier. MED…

Advanced WAN Services

Question

An engineer is designing a redundant dual-homed BGP solution that should prefer one specific carrier under normal conditions. Traffic should automatically fail over to a secondary carrier in case of a failure. Which two BGP attributes can be used to achieve this goal for inbound traffic?

Options

AAS-PATH
Bweight
Corigin
Dlocal preference
EMED

How the community answered

(21 responses)

A
62% (13)
B
24% (5)
C
10% (2)
D
5% (1)

Explanation

Inbound traffic is controlled by attributes that influence how external neighbors choose their exit path toward your AS. AS-PATH prepending (A) makes your AS appear farther away on one link, causing the remote carrier to prefer the shorter path - the primary carrier. MED (Multi-Exit Discriminator) (E) is sent to a neighboring AS to suggest which entry point to use when multiple links connect the same two ASes. Weight (B) and Local Preference (D) are outbound attributes that only affect routing decisions within your own AS. Origin (C) has very low influence and is not used for this purpose.

Topics

#BGP#AS-PATH#MED#inbound traffic engineering

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