14-100 show ip bgp neighbors ip-address routes

14-100 show ip bgp neighbors ip-address routes

Syntax Description:

• ip-address ” IP address of the BGP neighbor.

• line ” Regular expression. See Appendix B.

Purpose: To display routes with inconsistent originating autonomous systems. Soft inbound reconfiguration needs to be enabled before you use the received-routes form of this command.

Cisco IOS Software Release: 10.0. The received-routes keyword was added in Cisco IOS Software Release 11.2.

Example: Display Information for a Specific BGP Neighbor

The state of a BGP neighbor can be examined by using the show ip bgp neighbors command. This is usually the first command to use when debugging a BGP connection.

 rtrA#  show ip bgp neighbors 172.17.1.2  BGP neighbor is 172.17.1.2,  remote AS 1, external link   BGP version 4, remote router ID 199.172.15.1   BGP state = Established, up for 1w1d   Last read 00:00:43, hold time is 180, keepalive interval is 60 seconds   Neighbor capabilities:     Route refresh: advertised     Address family IPv4 Unicast: advertised and received   Received 13174 messages, 0 notifications, 0 in queue   Sent 13168 messages, 0 notifications, 0 in queue   Route refresh request: received 0, sent 0   Minimum time between advertisement runs is 30 seconds  For address family: IPv4 Unicast   BGP table version 14, neighbor version 14   Index 1, Offset 0, Mask 0x2   3 accepted prefixes consume 108 bytes   Prefix advertised 40, suppressed 0, withdrawn 0   Connections established 10; dropped 9   Last reset 1w1d, due to User reset Connection state is ESTAB, I/O status: 1, unread input bytes: 0 Local host: 172.17.1.1, Local port: 11106 Foreign host: 172.17.1.2, Foreign port: 179 Enqueued packets for retransmit: 0, input: 0  mis-ordered: 0 (0 bytes) Event Timers (current time is 0x357A31F8): Timer          Starts    Wakeups            Next Retrans         11859          0             0x0 TimeWait            0          0             0x0 AckHold         11862      11505             0x0 SendWnd             0          0             0x0 KeepAlive           0          0             0x0 GiveUp              0          0             0x0 PmtuAger            0          0             0x0 DeadWait            0          0             0x0 iss: 2220955579  snduna: 2221180949  sndnxt: 2221180949     sndwnd:  16327 irs: 1147082461  rcvnxt: 1147307991  rcvwnd:      16156  delrcvwnd:    228 SRTT: 300 ms, RTTO: 607 ms, RTV: 3 ms, KRTT: 0 ms minRTT: 0 ms, maxRTT: 376 ms, ACK hold: 200 ms Flags: higher precedence, nagle Datagrams (max data segment is 1460 bytes): Rcvd: 23247 (out of order: 0), with data: 11862, total data bytes: 225529 Sent: 23520 (retransmit: 0), with data: 11859, total data bytes: 225388 

The following list explains some of the fields that appear in the preceding output from the show ip bgp neighbors 172.17.1.2 command.

• BGP neighbor ” IP address and autonomous system number of the BGP neighbor. If the link is internal, the neighbors are in the same autonomous system. If the link is external, the neighbors are in different autonomous systems.

• remote AS ” BGP neighbor's autonomous system number.

• external link ” Indicates that this peer is an Exterior Border Gateway Protocol (EBGP) peer.

• BGP version ” BGP version that the neighbors are using.

• remote router ID ” The ID of the remote neighbor. The ID is the highest IP address assigned to a physical interface or the highest loopback address.

• BGP state ” Internal state of this BGP connection. If the state does not reach the Established state, there is a problem forming the BGP connection.

• up for ” Amount of time that the TCP connection has been established.

• Last read ” Time that BGP last read a message from this neighbor.

• hold time ” Maximum amount of time that can elapse between messages from the peer before the neighbor is declared down.

• keepalive interval ” Time period between sending keepalive packets. The keepalive interval is generally three times the hold time.

• Neighbor capabilities ” BGP capabilities advertised and received from this neighbor. If you are running code earlier than 12.0, you do not see this field.

• Route refresh ” Indicates that the neighbor supports dynamic soft reset using the route refresh capability. If you are running code earlier than 12.0, you do not see this field.

• Address family IPv4 Unicast ” IPv4 unicast-specific properties of this neighbor. If you are running code earlier than 12.0, you do not see this field.

• Address family IPv4 Multicast ” IPv4 multicast-specific properties of this neighbor. If you are running code earlier than 12.0, you do not see this field.

• Received ” Number of total BGP messages received from this peer, including keepalives .

• notifications ” Number of error messages received from this neighbor.

• Sent ” Total number of BGP messages that have been sent to this neighbor, including keepalives.

• notifications ” Number of error messages the router has sent to this neighbor.

• Route refresh request ” Number of route refresh requests sent to and received from this neighbor.

• advertisement runs ” Value of the minimum advertisement interval.

• For address family ” Address family to which the following fields refer.

• BGP table version ” Every time the BGP table changes, this number is incremented.

• neighbor version ” Number used by the software to track the prefixes that have been sent and those that have to be sent to this neighbor.

• Community attribute ” Appears if the neighbor send-community command is configured for this neighbor.

• Inbound path policy ” Indicates if an inbound policy is configured.

• Outbound path policy ” Indicates if an outbound policy is configured.

• mul-in ” Name of the inbound route map for the multicast address family.

• mul-out ” Name of outbound route map for the multicast address family.

• accepted prefixes ” Number of prefixes accepted.

• Prefix advertised ” Number of prefixes advertised.

• suppressed ” Number of prefixes suppressed.

• withdrawn ” Number of prefixes withdrawn.

• Connections established ” Number of times the router has established a TCP connection and the two peers have agreed to speak BGP with each other.

• dropped ” Number of times that a good connection has failed or been taken down.

• Last reset ” Elapsed time since this peering session was last reset.

• Connection state ” State of the BGP peer.

• unread input bytes ” Number of bytes of packets still to be processed .

• Local host, Local port ” Peering address of local router, plus port.

• Foreign host, Foreign port ” Neighbor's peering address.

• Event Timers Table ” Displays the number of starts and wakeups for each timer.

• iss ” Initial send sequence number.

• snduna ” Last send sequence number the local host sent but has not received an acknowledgment for.

• sndnxt ” Sequence number the local host will send next.

• sndwnd ” TCP window size of the remote host.

• irs ” Initial receive sequence number.

• rcvnxt ” Last receive sequence number the local host has acknowledged .

• rcvwnd ” Local host's TCP window size.

• delrecvwnd ” Delayed receive window. Data the local host has read from the connection but has not yet subtracted from the receive window the host has advertised to the remote host. The value in this field gradually increases until it is larger than a full- sized packet, at which point it is applied to the rcvwnd field.

• SRTT ” A calculated smoothed round-trip time-out.

• RTTO ” Round-trip time-out.

• RTV ” Variance of the round-trip time.

• KRTT ” New round-trip time-out (using the Karn algorithm). This field separately tracks the round-trip time of packets that have been retransmitted.

• minRTT ” Smallest recorded round-trip time-out (hard-wire value used for calculation).

• maxRTT ” Largest recorded round-trip time-out.

• ACK hold ” Time the local host will delay an acknowledgment in order to piggyback data on it.

• Flags ” IP precedence of the BGP packets.

• Datagrams Rcvd ” Number of update packets received from this neighbor.

• with data ” Number of update packets received with data.

• total data bytes ” Total bytes of data.

• Sent ” Number of update packets sent.

• with data ” Number of update packets with data sent.

• total data bytes ” Total number of data bytes.