BGP Established and Idle States

• Idle: The router in this state cannot find the address of the neighbor in the routing table. Check for an IGP problem. Is the neighbor announcing the route?

• Established: The established state is the proper state for BGP operations. In the output of the show ip bgp summary command, if the state column has a number, then the route is in the established state. The number is how many routes have been learned from this neighbor.

The idle state is an indication that the router does not know how to reach the IP address that is listed in the neighbor statement. The router is idle because of one of the following scenarios:

■ It is waiting for a static route to that IP address or network to be configured.

■ It is waiting for the local routing protocol (IGP) to learn about this network through an advertisement from another router.

The most common reason for a router to enter the idle state is that the neighbor is not announcing the IP address or network that the neighbor statement of the router is pointing to. Check these two conditions first to correct this problem:

■ Ensure that the neighbor announces the route in its local routing protocol (IGP).

■ Verify that you have not entered an incorrect IP address in the neighbor statement.

The established state is the desired state for the neighbor relationship. This state means that both routers have agreed to exchange BGP updates with one another and routing has begun.

6-66 Building Scalable Cisco Internetworks (BSCI) v3.0 © 2006 Cisco Systems, Inc.

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