Reference Guide

Storing Last and Bad PDUs
The system stores the last notification sent/received and the last bad protocol data unit (PDU) received on a per peer basis.
The last bad PDU is the one that causes a notification to be issued.
In the following example, the last seven lines shown in bold are the last PDUs.
Example of the show ip bgp neighbor Command to View Last and Bad PDUs
Dell(conf-router_bgp)#do show ip bgp neighbors 1.1.1.2
BGP neighbor is 1.1.1.2, remote AS 2, external link
BGP version 4, remote router ID 2.4.0.1
BGP state ESTABLISHED, in this state for 00:00:01
Last read 00:00:00, last write 00:00:01
Hold time is 90, keepalive interval is 30 seconds
Received 1404 messages, 0 in queue
3 opens, 1 notifications, 1394 updates
6 keepalives, 0 route refresh requests
Sent 48 messages, 0 in queue
3 opens, 2 notifications, 0 updates
43 keepalives, 0 route refresh requests
Minimum time between advertisement runs is 30 seconds
Minimum time before advertisements start is 0 seconds
Capabilities received from neighbor for IPv4 Unicast :
MULTIPROTO_EXT(1)
ROUTE_REFRESH(2)
CISCO_ROUTE_REFRESH(128)
Capabilities advertised to neighbor for IPv4 Unicast :
MULTIPROTO_EXT(1)
ROUTE_REFRESH(2)
CISCO_ROUTE_REFRESH(128)
For address family: IPv4 Unicast
BGP table version 1395, neighbor version 1394
Prefixes accepted 1 (consume 4 bytes), 0 withdrawn by peer
Prefixes advertised 0, rejected 0, 0 withdrawn from peer
Connections established 3; dropped 2
Last reset 00:00:12, due to Missing well known attribute
Notification History
'UPDATE error/Missing well-known attr' Sent : 1 Recv: 0
'Connection Reset' Sent : 1 Recv: 0
Last notification (len 21) sent 00:26:02 ago
ffffffff ffffffff ffffffff ffffffff 00160303 03010000
Last notification (len 21) received 00:26:20 ago
ffffffff ffffffff ffffffff ffffffff 00150306 00000000
Last PDU (len 41) received 00:26:02 ago that caused notification to be issued
ffffffff ffffffff ffffffff ffffffff 00290200 00000e01 02040201 00024003 04141414 0218c0a8
01000000
Local host: 1.1.1.1, Local port: 179
Foreign host: 1.1.1.2, Foreign port: 41758
Capturing PDUs
To capture incoming and outgoing PDUs on a per-peer basis, use the capture bgp-pdu neighbor direction command.
To disable capturing, use the no capture bgp-pdu neighbor direction command.
The buffer size supports a maximum value between 40 MB (the default) and 100 MB. The capture buffers are cyclic and
reaching the limit prompts the system to overwrite the oldest PDUs when new ones are received for a given neighbor or
direction. Setting the buffer size to a value lower than the current maximum, might cause captured PDUs to be freed to set the
new limit.
NOTE: Memory on RP1 is not pre-allocated and is allocated only when a PDU needs to be captured.
The buffers storing the PDU free memory when:
170
Border Gateway Protocol IPv4 (BGPv4)