300-415 Question 149
Single answerA network engineer is deploying Cisco SD-WAN in a hybrid architecture with OSPF running in the underlay network. The requirement is to ensure that OSPF routes from the branch sites are redistributed into the SD-WAN overlay and vice versa. Which configuration step is required to ensure proper OSPF route redistribution in this scenario?
- A
Configure OSPF as a service VPN in the vManage template and enable route redistribution.
- B
Enable OSPF adjacency between the vEdge routers and all underlay routers.
- C
Configure OMP to advertise OSPF routes and enable redistribution between OMP and OSPF.
- D
Enable BGP peering between vEdge routers and underlay routers to carry OSPF routes.
Show answer and explanation
Correct answer: C
Explanation
In Cisco SD-WAN, OMP (Overlay Management Protocol) is the key protocol for managing route advertisements within the overlay network. When OSPF is used in the underlay, the OSPF routes need to be redistributed into OMP for propagation across the SD-WAN fabric. Similarly, OMP advertises routes back to OSPF for reachability. This ensures proper connectivity and route exchange between the underlay and overlay. Configuring OMP for OSPF route redistribution is the correct approach.
- A. Incorrect.
This option is incorrect because OSPF as a service VPN is configured to define OSPF inside a specific VPN, but it does not directly handle redistribution into the overlay.
- B. Incorrect.
This option is incorrect because OSPF adjacency is not directly established between vEdge routers and the underlay routers. Instead, OSPF routes are redistributed into the overlay via OMP.
- C. Correct.
This option is correct because OMP is the protocol used in Cisco SD-WAN to advertise routes (including OSPF routes) across the overlay. Configuring OMP to redistribute OSPF routes ensures seamless route exchange between the underlay and overlay.
- D. Incorrect.
This option is incorrect because enabling BGP peering with underlay routers is not necessary for OSPF redistribution in Cisco SD-WAN. OMP handles route advertisement and redistribution within the SD-WAN fabric.