Implementing Cisco Networking Solutions

Troubleshooting routing issues

Routing is fundamental to the forwarding of packets in an IP network, as the routing processes define the path that an IP packet would take at each routed hop. The router builds the routing table using statically defined routes or running routing protocols, such as RIP, OSPF, and ISIS. The routing table defines the next hop for an IP packet with a given destination address.

The routing table on a Cisco device can be seen using the show ip route command. A sample output of the command is as shown in the following image:

Figure 21: Display of the IP routing table

The output shows that the routed prefix, the next ...