Exam 400-007 topic 1 question 13 discussion

The question is about network re-convergence with PBR - not issues associated with PBR

Disregard my previous answer of D - should be B:

Answer is D: Increased Convergence Time: Policy-based routing can complicate the routing process because it allows for routing decisions based on policies other than the standard routing table. During network reconvergence, the network must not only reestablish the best paths based on traditional routing protocols but also reapply the policies that govern PBR. This additional step can slow down the overall convergence process, leading to increased convergence time.

For me, the issue with PBR is more the limited scalability. With a propoer PBR configuration, there are no loops.

Given the context of the question about reconvergence and PBR, the most relevant concern is: B. It can create microloops during reconvergence.

I choose B Policy-based routing (PBR) can be used to implement a variety of routing policies, but it can also introduce potential problems with network reconvergence. One such problem is the possibility of creating microloops. A microloop is a loop that is created between two or more devices in a network. Microloops can cause traffic to circulate between the devices indefinitely, which can lead to performance problems and even network outages. Microloops can be created during reconvergence if PBR is not configured correctly. For example, if a PBR rule is configured to route traffic over a link that is down, the traffic may be looped back to the source device.

Answer should be A Policy-based routing adds flexibility and control that other routing techniques do not, however. It gives you a level of control that a routing protocol by itself can’t accomplish. With flexibility, there is typically a cost, and in this case, it’s scalability and manageability. https://www.globalknowledge.com/us-en/resources/resource-library/articles/policy-based-routing-what-is-it-and-how-is-it-used/#gref

Answer should be A Policy-based routing adds flexibility and control that other routing techniques do not, however. It gives you a level of control that a routing protocol by itself can’t accomplish. With flexibility, there is typically a cost, and in this case, it’s scalability and manageability. https://www.globalknowledge.com/us-en/resources/resource-library/articles/policy-based-routing-what-is-it-and-how-is-it-used/#gref