An engineer configured two routers connected to two different service providers using BGP with default attributes. One of the links is presenting high delay, which causes slowness in the network.
Which BGP attribute must the engineer configure to avoid using the high-delay ISP link if the second ISP link is up?
The necessary attribute to configure is Local Preference (LOCAL_PREF). Local Preference is used within an autonomous system to choose between multiple exit paths for outbound traffic. By setting a higher Local Preference value for the preferred link and a lower one for the high-delay link, the engineer can ensure that BGP will prefer the lower-delay link for outbound traffic as long as it is available. This helps in avoiding the high-delay link when the second ISP link is up.
The engineer should configure the LOCAL_PREF attribute to avoid using the high-delay ISP link if the second ISP link is up. LOCAL_PREF allows you to prioritize routes within the local autonomous system, ensuring that the lower-delay link is preferred for outbound traffic. Correct answer is option : D
It D. The key word is TWO routers in the AS. We need a solution that works for both, and only needs to be configured once. Yes, weight could work, however it isnt the best solution here since its locally significant.
The answer is D, The Local Preference attribute is used: To choose between multiple exit paths from your network - Non-transitive and optional attribute - Local to an AS only * Default local preference is 100 (IOS) - Used to influence BGP path selection * Determines the best path for outbound traffic - Path with highest local preference wins
A and 100% sure
AS_PATH prepends allows you to ensure that returning traffic to the network uses path with the short AS-Path. I will go with AS-Path because with it, one can influence how traffic returns from the rest of the world. Local preference only determines how traffic exits the network if there are multiple routers so this is wrong. MED is like metric, MED is what we learn from our upstream service provider or we set the Med on the way in. But Med only chooses the exit link not how the traffic returns.
Local Preference is correct, apologies. There are multiple routers.
The production world answer for this is both A and D, prepend adverts out the slower link and use local preference to exit out the better link. The cisco answer is local preference as they mention 2 routes which is the key here.
D is correct: Three steps are by far the most important ones. Prefer the path with the highest local preference Prefer the path with the shortest AS path Prefer the path with the lowest multi-exit discriminator (MED)
I think it is A. only A is possible to affect choosing for both directions. The other options only affect one direction.
Can you say you avoided using one link if only one direction is not using the link but the other direction continues to use it?
I choose D. Because the question said he is configuring the "2" router connecting to ISP, if he can configure the router connecting to the two routers, he can change the WEIGHT. But if he is on the two router, the only config that can influence other is Local_Pref.
B weight
The given answer is correct
weight is local to router. In the question we have two routers connected to two ISPs. Local_pref is exchanged between IBGP peers. D is correct answer.
D is correct You can use local preference to choose the outbound external BGP path.
Weight is the correct answer
No, weight is local to router. In the question we have two routers connected to two ISPs. Local_pref is exchanged between IBGP peers. D is correct answer.
D IS CORRECT
The given answer is correct
If the question stated TWO cisco routers, then the answer would be B. Setting the weight with an inbound route map, you can influence outbound traffic. The same goes for local preference, second attribute in the list of preference in cisco routers, but first in non-cisco routers. I agree that the answer should be D.
I choose D
i think it's A
Both options A and C, influence inbound routing from external systems. Not relevant, here, as we are trying to influence outbound path selection. Given that the engineer is dealing with two routers connected to different ISPs, using LOCAL_PREF is preferred because it ensures that the preference is consistent across the entire AS, not just on a single router. So, while configuring **weight** can achieve a similar outcome on a single router, **local preference** is generally preferred for broader and more consistent influence across all routers within the AS.
D is correct