How can you troubleshoot interoperability issues between routing protocols?

2 Verify the redistribution

The second step is to verify the redistribution of routes between different routing protocols. Redistribution is the process of importing and exporting routes from one routing domain to another, and it requires careful configuration to avoid conflicts, loops, or suboptimal paths. You can use the show ip route command to check if the routes from one routing protocol are correctly redistributed to another, and if they have the appropriate administrative distance and metric values. You can also use the debug ip routing command to monitor the routing updates and events in real time.

3 Adjust the metrics

The third step is to adjust the metrics of the routing protocols to ensure consistent and optimal routing decisions. Metrics are the values that measure the cost or desirability of a route, and different routing protocols use different metrics and scales. For example, EIGRP uses a composite metric based on bandwidth, delay, reliability, and load, while OSPF uses a simple metric based on bandwidth. When redistributing routes between different routing protocols, you need to convert or manipulate the metrics to avoid discrepancies or preference issues. You can use the metric or default-metric keywords in the redistribution commands to specify the metric values for the redistributed routes.

4 Resolve the conflicts

The fourth step is to resolve the conflicts that may occur between different routing protocols due to overlapping or mismatched network addresses, subnet masks, or area IDs. Conflicts can cause routing loops, unreachable networks, or inconsistent routing tables. You can use the show ip route command to identify any conflicts in the network topology, and use the ip summary-address or area range commands to create summary routes or aggregate addresses to reduce the number of routes and avoid conflicts. You can also use the network or redistribute commands to specify the exact network addresses or prefixes that belong to each routing protocol.

5 Test the connectivity

The fifth step is to test the connectivity and performance of the network after troubleshooting the interoperability issues. You can use various commands and tools to ping, traceroute, or measure the bandwidth, latency, or packet loss of the network. For example, you can use the ping , traceroute , show ip sla statistics , and show ip route summary commands on Cisco routers to test the connectivity and performance of the IP routing protocols. You can also use the show ip protocols summary command to verify the status and statistics of the routing protocols.

6 Document the changes

The sixth and final step is to document the changes that you have made to the network configuration and the results of the troubleshooting process. Documentation is important for maintaining the network security, reliability, and consistency, and for future reference and analysis. You can use various methods and formats to document the network changes, such as logs, diagrams, reports, or templates. You can also use the show running-config or show startup-config commands on Cisco routers to display the current or saved configuration of the routers, and use the copy running-config startup-config or write commands to save the changes to the non-volatile memory.