300-415 Question 27
Select 2A network engineer is troubleshooting routing issues in a Cisco SD-WAN deployment. The engineer observes that a vEdge router is not receiving certain route updates from other vEdge routers in the overlay network. Upon further investigation, the engineer finds that the routes are present in the vSmart's route table but are not being advertised to the affected vEdge. Which of the following could be the cause of this issue?
- A
The vEdge router does not have the correct TLOC configured to establish connectivity with the vSmart.
- B
A policy applied on the vSmart is preventing the specific routes from being advertised to the vEdge.
- C
The affected vEdge router has an incorrect site ID configured.
- D
The vSmart controller has a misconfigured OMP session with the affected vEdge router.
- E
The affected vEdge router is running an incompatible software version with the vSmart controller.
Show answer and explanation
Correct answers: A, B
Explanation
In Cisco SD-WAN, the vSmart controller uses OMP (Overlay Management Protocol) to distribute routing information to vEdge routers. If a vEdge router fails to receive certain routes, potential causes include TLOC misconfigurations (which impact connectivity) or policies applied on the vSmart that restrict route advertisement. Other issues, such as site ID mismatches or OMP misconfigurations, typically result in broader connectivity problems instead of selective route issues.
- A. Correct.
Correct. If the vEdge router does not have the correct TLOC configuration, it will not form a proper connection to the vSmart, which could lead to missing route updates.
- B. Correct.
Correct. Policies on the vSmart, such as centralized control policies, can filter or block specific routes from being advertised to certain devices.
- C. Incorrect.
Incorrect. While site ID discrepancies can cause communication issues in some scenarios, they would typically prevent the router from joining the overlay entirely rather than causing selective route advertisement issues.
- D. Incorrect.
Incorrect. A misconfigured OMP session could prevent the vEdge router from receiving any routes, but it is less likely to cause issues with only specific routes.
- E. Incorrect.
Incorrect. Software version incompatibility could cause systemic issues in the SD-WAN fabric, but it is not directly related to selective route advertisement.