Avoiding Redundant Route Learning in Cisco SD-WAN Solution

Configuring Redistribution to Prevent Redundant Route Learning in Cisco SD-WAN

Question

When redistribution is configured between OMP and BGP at two Data Center sites (DC) that have Direct Connection Interlink, which step avoids learning the same routes on WAN Edge routers of the DCs from LAN?

Answers

Explanations

Click on the arrows to vote for the correct answer

A. B. C. D.

BD.

When redistributing routes between OMP (Overlay Management Protocol) and BGP (Border Gateway Protocol) in two Data Center sites that have a direct connection interlink, there is a risk of learning the same routes on WAN Edge routers of the Data Centers from LAN. To avoid this, one of the following steps should be taken:

B. Define different VRFs on both DCs: A VRF (Virtual Routing and Forwarding) is a technology that allows multiple instances of a routing table to coexist within the same router. By defining different VRFs on both Data Centers, routes learned from OMP and BGP can be kept separate, preventing the learning of the same routes on WAN Edge routers of the Data Centers from LAN.

A. Set down-bit on WAN Edge routers on DC1: The down-bit is a flag that is set on a packet to indicate that it should not be sent over the WAN. This step would not prevent the learning of the same routes on WAN Edge routers of the Data Centers from LAN.

C. Set OMP admin distance lower than BGP admin distance: Admin distance is a measure of the trustworthiness of a routing protocol, and a lower value indicates a higher level of trustworthiness. By setting the OMP admin distance lower than the BGP admin distance, the WAN Edge routers would prefer the OMP routes over the BGP routes. However, this step alone would not prevent the learning of the same routes on WAN Edge routers of the Data Centers from LAN.

D. Set same overlay AS on both DC WAN Edge routers: The overlay AS (Autonomous System) is a number used to identify a particular SD-WAN overlay network. Setting the same overlay AS on both Data Center WAN Edge routers would ensure that they are part of the same overlay network, but it would not prevent the learning of the same routes on WAN Edge routers of the Data Centers from LAN.

Therefore, the correct answer is B. Define different VRFs on both DCs.