Assuming all links have the same cost, how many entries for prefix 192.168.3.0/24 will be in router R3’s routing table?

Refer to the exhibit.

All routers in the diagram are running an interior gateway protocol (IGP) and have been configured with an ECMP value of 4. Router R5 advertises the prefix 192.168.3.0/24 using the IGP.

Assuming all links have the same cost, how many entries for prefix 192.168.3.0/24 will be in router R3’s routing table?
A . 1
B . 2
C . 3
D . 4

View Answer

Answer: D

Explanation:

In this scenario, the routers are configured with an Equal-Cost Multi-Path (ECMP) value of 4, meaning they can utilize up to 4 equal-cost paths to reach a destination. Since Router R5 is advertising the 192.168.3.0/24 prefix and all links have the same cost, router R3 will receive multiple routes to reach this destination.

Given that all the routers (R1, R2, R3, R4, and R5) are connected in a way that can support multiple equal-cost paths, and assuming ECMP is set to 4, the routing table on Router R3 will have up to 4 entries for the prefix 192.168.3.0/24.

Thus, Router R3’s routing table will contain 4 entries for the prefix 192.168.3.0/24.