Packet Captures

BGP_MD5.cap (1.7 KB)

Submitted November 26, 2009

Packets: 16	Duration: 61s	Downloads: 621

An EBGP with TCP MD5 authentication enabled

Categories: Authentication, Routing Protocols
Protocols: BGP, Ethernet, IP, TCP

BGP_redist.cap (378 bytes)

Submitted October 28, 2009 by colinbsd

Packets: 2	Duration: n/a	Downloads: 531

The OSPF metric is preserved and propagated within the MPLS cloud by the MP-BGP MED attribute.

Categories: Routing Protocols
Protocols: BGP, HDLC, IP, MPLS, TCP

IBGP_adjacency.cap (2.3 KB)

Submitted September 14, 2009

Packets: 17	Duration: 63s	Downloads: 373

Routers 3 and 4 form an internal BGP relationship. This is evidenced by the OPEN messages in packets #4 and #5, which show both routers belong to the same AS (65300). Also note that IBGP packets are not subject to a limited TTL as are EBGP packets.

Categories: Routing Protocols
Protocols: BGP, Ethernet, IP, TCP

EBGP_adjacency.cap (2.7 KB)

Submitted September 14, 2009

Packets: 24	Duration: 182s	Downloads: 362

The external BGP adjacency between routers 1 and 2 is brought online and routes are exchanged. Keepalives are then exchanged every 60 seconds. Note that the IP TTL (normally 1) has been increased to 2 with ebgp-multihop to facilitate communication between the routers' loopback interfaces.

Categories: Routing Protocols
Protocols: BGP, Ethernet, IP, TCP

BGP_soft_reset.cap (2.0 KB)

Submitted September 14, 2009

Packets: 17	Duration: 180s	Downloads: 344

R1 performs a soft bidirectional reset (clear ip bgp soft) on its adjacency with R2. The ROUTE-REFRESH message is visible in packet #7. Note that the TCP connection remains uninterrupted, and neither router views the reset as disruptive.

Categories: Routing Protocols
Protocols: BGP, Ethernet, IP, TCP

BGP_notification.cap (764 bytes)

Submitted September 14, 2009

Packets: 9	Duration: n/a	Downloads: 372

R1 has been misconfigured to expect R2 to reside in AS 65100. R2 attempts to peer with R1 advertising itself correctly in AS 65200. R1 issues a NOTIFICATION in packet #5 citing a "bad peer AS" error and terminates the TCP connection.

Categories: Routing Protocols
Protocols: BGP, Ethernet, IP, TCP

BGP_hard_reset.cap (3.2 KB)

Submitted September 14, 2009

Packets: 32	Duration: 208s	Downloads: 324

A hard reset (clear ip bgp) is performed on R1 for its adjacency with R2. Packet #7 shows R1 sending a packet with the TCP FIN flag set, indicating the connection is to be torn down. The TCP connection is then reestablished and UPDATEs are retransmitted.