Need help with a Cisco 2 Question.

dtweaponx

A router is configured to participate in multiple routing protocol: RIP, EIGRP, and OSPF. The router must send a packet to network 192.168.14.0. Which route will be used to forward the traffic?
a 192.168.14.0/26 route that is learned via RIP*
a 192.168.14.0/24 route that is learned via EIGRP
a 192.168.14.0/25 route that is learned via OSPF
a 192.168.14.0/25 route that is learned via RIP


Question is how did they get /26 from the original 192.168.14.0 network. Why is it /26 instead of /25?



Thanks.

Neil86

The big thing in the question is the use of different masks. Even though the first 3 octects match, the masks tell you they are different subnets. When the router recieves a packet destined for 192.168.14.0, it's going to select a matching subnet route with the longest prefix.

Now, if they all had the same masks, it would select based on AD, the EIGRP route would be selected.

There are multiple scenarios where multipe routes may exist using different protocols, and different routes are chosen for each:

https://www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway-routing-protocol-eigrp/8651-21.html