3-16 bgp log-neighbor-changes

3-16 bgp log-neighbor-changes

Syntax Description:

This command has no arguments.

Purpose: To enable the logging of changes in a BGP neighbor's status. If the UNIX syslog facility is enabled, messages can be sent to a UNIX host running the syslog daemon. If you are not using the UNIX syslog facility, the status change messages are stored in the router's internal buffer. Events that are logged include the following:

• BGP protocol initialization

• No memory for path entry

• No memory for attribute entry

• No memory for prefix entry

• No memory for aggregate entry

• No memory for dampening info

• No memory for BGP updates

• BGP notification received

• Erroneous BGP update received

• User reset request

• Peer time-out

• Password change

• Error during connection collision

• Peer closing down the session

• Peer exceeding maximum prefix limit

• Interface flap

• Router ID changed

• Neighbor deleted

• Member added to peer group

• Administrative shutdown

• Remote AS changed

• RR client configuration modification

• Soft reconfiguration modification

Cisco IOS Software Release: 11.1 CC and 12.0

Configuration Example 1: Enabling BGP Neighbor Status Change Logging to the Console

To enable the display of BGP neighbor status change events on the console, use the following configuration:

  router bgp 1    bgp log-neighbor-changes    neighbor 172.17.1.1 remote-as 2  

Verification

When the state of a BGP neighbor changes, the event should be displayed on the console. For example, if you execute the command clear ip bgp * on a BGP neighbor, the following output should be displayed:

 rtr# 01:10:52: %BGP-5-ADJCHANGE: neighbor 172.17.1.2 Down - Peer closed the session 01:11:22: %BGP-5-ADJCHANGE: neighbor 172.17.1.2 Up 

Configuration Example 2: Enabling BGP Neighbor Status Change Logging to Memory

To enable the logging of BGP neighbor status change events to memory, use the following configuration:

   logging buffered 4096 debugging    !   router bgp 1    bgp log-neighbor-changes    neighbor 172.17.1.1 remote-as 2  

The parameters 4096 and debugging are default values and are supplied by the router when you use the command logging buffered. The default values vary by platform.

Verification

The show logging command displays the status of buffered logging. If logging is enabled, the contents of the buffer are displayed:

 rtr#  show logging  Syslog logging: enabled (0 messages dropped, 0 flushes, 0 overruns)     Console logging: level debugging, 48 messages logged     Monitor logging: level debugging, 0 messages logged  Buffer logging: level debugging, 3 messages logged  Trap logging: level informational, 51 message lines logged Log Buffer (4096 bytes): 01:18:16: %SYS-5-CONFIG_I: Configured from console by console 01:18:31: %BGP-5-ADJCHANGE: neighbor 172.17.1.2 Down - Peer closed the session 01:19:00: %BGP-5-ADJCHANGE: neighbor 172.17.1.2 Up 

Troubleshooting

Step 1. Verify that the BGP neighbors are in the Established state using the show ip bgp neighbors command.

If the neighbor relationship is not in the Established state, see section 8-23.

Step 2. Verify that buffered logging is enabled using the show logging command.