CCNP ENARSI Certification Cram Notes

The CCNP ENARSI (Implementing Cisco Enterprise Advanced Routing and Services) exam tests a candidate's knowledge and skills related to implementing advanced routing technologies and services in enterprise networks. The exam objectives are as follows:

1.0 Layer 3 Technologies
2.0 VPN Technologies
3.0 Infrastructure Security
4.0 Infrastructure Services
5.0 CCNP ENARSI sample MCQs

1.0 Layer 3 Technologies

1.1 Troubleshoot administrative distance (all routing protocols)

Administrative distance (AD) is a measure of the trustworthiness of a routing information source. It is used by routers to determine which route to use when there are multiple paths to a destination network that have been learned from different sources. The lower the AD value, the more trustworthy the source is considered to be.

Important steps to troubleshoot AD issues in all routing protocols:

1. Check the AD values for the routing protocols being used. The AD values for different routing protocols are predefined, and can be found in Cisco documentation. Make sure that the AD values being used are appropriate for the network topology and routing requirements.

2. Verify that the routing protocols are configured correctly on all routers. Check the configuration for errors or missing settings. Ensure that the routing protocols are enabled on the correct interfaces, and that the correct networks are being advertised.

3. Check the routing table on each router. Verify that the routing table is populated with the expected routes, and that the AD values are correct for each route.

4. Verify that the routers are exchanging routing information correctly. Check for connectivity between routers, and ensure that the correct routing updates are being sent and received.

5. Use debug commands to troubleshoot AD issues. Debugging can provide valuable information about routing protocol behavior and can help to identify configuration errors or network connectivity problems.

6. Check for duplicate routes. Duplicate routes can cause issues with AD, as routers may choose the incorrect route based on AD values. Use the "show ip route" command to check for duplicate routes and remove any that are unnecessary.

By following these troubleshooting steps, you can identify and resolve AD issues in all routing protocols.