200-301 Question 267
Single answerA network engineer is troubleshooting a routing issue on a router. When using the 'show ip route' command, they notice the following entries:
C 192.168.1.0/24 is directly connected, GigabitEthernet0/1 O 10.0.0.0/8 [110/2] via 192.168.1.2, 00:00:07, GigabitEthernet0/1 D 172.16.0.0/16 [90/2172416] via 192.168.1.3, 00:00:45, GigabitEthernet0/1
Which routing protocol is responsible for learning the route to the 172.16.0.0/16 network?
- A
OSPF
- B
RIP
- C
EIGRP
- D
BGP
Show answer and explanation
Correct answer: C
Explanation
In a Cisco routing table, each route is marked with a specific code to indicate the routing protocol that learned the route. The 'D' code in the routing table represents routes learned via EIGRP (Enhanced Interior Gateway Routing Protocol). Since the 172.16.0.0/16 route is marked with 'D', it was learned through EIGRP. Understanding routing protocol codes is crucial for identifying the source of routing information in network troubleshooting scenarios.
- A. Incorrect.
OSPF routes are indicated by the 'O' code in the routing table. However, the entry for the 172.16.0.0/16 network is marked with 'D', which is not associated with OSPF.
- B. Incorrect.
RIP routes are indicated by the 'R' code in the routing table. The 'D' code in this case does not represent RIP.
- C. Correct.
EIGRP routes are indicated by the 'D' code in the routing table, which stands for 'DUAL' (Diffusing Update Algorithm) used by EIGRP. This makes EIGRP the correct answer for the 172.16.0.0/16 route.
- D. Incorrect.
BGP routes are indicated by the 'B' code in the routing table. The 'D' code in this case does not represent BGP.