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| 9.4 |  | Monitoring BGP Operation |
| 9.4.1 |  | Verifying BGP operation |

Verify BGP operation by using the key show commands.

If the router has not installed the BGP routes expected, use the

show ip bgp command to verify that BGP has learned these routes.

Notice that the output of this command includes the BGP table version number, which increments each time the local router receives changed route information. The AS_Path, among other key attributes, is also included in this table. Routes that are considered the best are denoted by the > character and are installed in the router IP routing table.

An expected BGP route may not appear in the BGP table. If this happens, use the

show ip bgp neighbors command to verify that the router has established a BGP connection with its neighbors. The most important information output of this command is the BGP state that exists between the neighbors. Anything other than "Established" indicates that the peers are not fully communicating.

The

show ip bgp neighbors command supports a number of optional parameters and syntax.

| Lab Activity e-Lab Activity: Verifying BGP Operation This lab is to verify that the BGP operations on all three routers are correct.

| Web Links Configuring BGP http://www.cisco.com/en/US/products/ sw/iosswrel/ps1828/products_configuration_ guide_chapter09186a00800ca571.html