300-420 Question 35
Select 2An enterprise network is configured with multiple BGP paths to the same destination. The network administrator wants to ensure that traffic is routed through a specific path based on BGP path attributes. Which combination of attributes should the administrator prioritize to influence outbound traffic while maintaining control over path selection?
- A
Local Preference
- B
AS Path
- C
Multi-Exit Discriminator (MED)
- D
Weight
- E
Origin
Show answer and explanation
Correct answers: A, D
Explanation
To influence outbound traffic, Local Preference and Weight are the most effective BGP attributes. Local Preference is applied across all routers in the same AS, while Weight is a Cisco-specific attribute that affects only the local router. These attributes allow the administrator to control which path is preferred for outbound traffic, ensuring optimal routing.
- A. Correct.
Local Preference is a key attribute used to influence outbound traffic within an autonomous system. It is applied to all routers in the AS and helps prioritize specific routes.
- B. Incorrect.
AS Path is primarily used to influence inbound traffic by preferring shorter paths, but it is less effective for outbound traffic control.
- C. Incorrect.
The Multi-Exit Discriminator (MED) is used to influence inbound traffic when multiple links exist between two autonomous systems. It does not directly control outbound traffic.
- D. Correct.
Weight is a Cisco-specific attribute that directly influences outbound traffic on the local router. It is the highest-priority attribute for outbound path preference.
- E. Incorrect.
The Origin attribute indicates how a route was introduced into BGP (e.g., IGP or EGP). It is not used to directly influence outbound path preference.