Configuring BGP4

The TCP statistics at the end of the display show status for the TCP session with the neighbor. Most of the fields show information stored in the routing switch’s Transmission Control Block (TCB) for the TCP session between the routing switch and its neighbor. These fields are described in detail in section 3.2 of RFC 793, “Transmission Control Protocol Functional Specification”.

In this example, a specific neighbor’s IP address is entered. The command therefore shows information only for that neighbor. None of the other options are used; thus, all the information about the neighbor is displayed. The numbers in the leftmost column separate the entries for each neighbor.

Syntax: show ip bgp neighbors [<ip-addr> [advertised-routes [detail [<ip-addr>[/<mask-bits>]]]] [attribute-entries [detail]] [flap-statistics] [last-packet-with-error]

[received-routes [best] [detail [best] [not-installed-best] [unreachable]] [rib-out-routes [<ip-addr>/<mask-bits> <ip-addr> <net-mask> detail]] [routes-summary]]

The <ip-addr> option lets you narrow the scope of the command to a specific neighbor.

The advertised-routesoption displays only the routes that the routing switch has advertised to the neighbor during the current BGP4 neighbor session.

The attribute-entriesoption shows the attribute-entries associated with routes received from the neighbor.

The flap-statisticsoption shows the route flap statistics for routes received from or sent to the neighbor.

The last-packet-with-errordisplays a hexadecimal dump of the first 400 bytes of the last packet received from the neighbor that contained an error.

The received-routesoption lists the routes received in UPDATE messages from the neighbor. You can specify the following additional options:

•best – Displays the routes received from the neighbor that the routing switch selected as the best routes to their destinations.

•not-installed-best– Displays the routes received from the neighbor that are the best BGP4 routes to their destinations, but were nonetheless not installed in the IP route table because the routing switch received better routes from other sources (such as OSPF, RIP, or static IP routes).

•unreachable – Displays the routes that are unreachable because the routing switch does not have a valid RIP, OSPF, or static route to the next hop.

•detail – Displays detailed information for the specified routes. You can refine your information request by also specifying one of the options above (best, not-installed-best, or unreachable).

The rib-out-routesoption lists the route information base (RIB) for outbound routes. You can display all the routes or specify a network address.

The routes-summaryoption displays a summary of the following information:

•Number of routes received from the neighbor

•Number of routes accepted by this routing switch from the neighbor

•Number of routes this routing switch filtered out of the UPDATES received from the neighbor and did not accept

•Number of routes advertised to the neighbor

•Number of attribute entries associated with routes received from or advertised to the neighbor.

This display shows the following information.

 

Table 10.6: BGP4 Neighbor Information

 

 

 

This Field...

 

Displays...

 

 

 

IP Address

 

The IP address of the neighbor.

 

 

 

AS#

 

The AS the neighbor is in.

 

 

 

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