Packet Captures
4-byte_AS_numbers_Full_Support.cap 1.2 KB
Submitted Apr 30, 2010 by pierky
Router at 172.16.1.2 (hostname "D", AS 40.1 / 2621441) clears a previous established peering with 172.16.1.1 (hostname "A", AS 10.1 / 655361); They both support 32-bit ASN.
While opening the new session, they negotiate the "Four-octet AS Number Capability" (pkts n. 2 and 3).
Then, both "A" and "D" send some UPDATEs containing 4-octect encoded AS_PATH attributes (pkts n. 6 and 9). Please note: WireShark may show wrong paths unless you force 4-byte encoding in the Preferences / Protocols / BGP options.
| Packets: 9 | Duration: 56s | Downloads: 8906 |
4-byte_AS_numbers_Mixed_Scenario.cap 414 bytes
Submitted Apr 30, 2010 by pierky
Router "B" (AS 2) at 172.16.3.2 does not support 4-byte AS numbers, while router "A" (AS 10.1 / 655361) at 172.16.3.1 does.
Router "A" receives an UPDATE for the 40.0.0.0/8 subnet from an external router ("D") in the AS 40.1 / 2621441 (not shown), and it forwards it to "B" (pkt n. 2): AS_PATH contains "23456 23456" (the first stands for AS 10.1, the second for the originating AS 40.1), but NEW_AS_PATH contains the real 4-byte AS numbers.
At pkt n. 3 "B" receives the same subnet directly from "D" and sends it to "A", including the original NEW_AS_PATH attribute previously appended by "D".
| Packets: 4 | Duration: 60s | Downloads: 9551 |
BGP_AS_set.cap 1.6 KB
Submitted Sep 14, 2009
Packet #15 includes a BGP update containing both an AS sequence and an AS set in its AS path attribute.
| Packets: 18 | Duration: 1s | Downloads: 7991 |
BGP_MD5.cap 1.7 KB
Submitted Nov 26, 2009
An EBGP with TCP MD5 authentication enabled
| Packets: 16 | Duration: 61s | Downloads: 10882 |
BGP_MP_NLRI.cap 2.9 KB
Submitted Jun 28, 2010
IPv6 routes are carried as a separate address family inside MP_REACH_NLRI attributes.
| Packets: 24 | Duration: 60s | Downloads: 16615 |
BGP_hard_reset.cap 3.2 KB
Submitted Sep 14, 2009
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.
| Packets: 32 | Duration: 208s | Downloads: 6656 |
BGP_notification.cap 764 bytes
Submitted Sep 14, 2009
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.
| Packets: 9 | Duration: n/a | Downloads: 7022 |
BGP_redist.cap 378 bytes
Submitted Oct 28, 2009 by colinbsd
The OSPF metric is preserved and propagated within the MPLS cloud by the MP-BGP MED attribute.
| Packets: 2 | Duration: n/a | Downloads: 10068 |
BGP_soft_reset.cap 2.0 KB
Submitted Sep 14, 2009
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.
| Packets: 17 | Duration: 180s | Downloads: 6761 |
EBGP_adjacency.cap 2.7 KB
Submitted Sep 14, 2009
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.
| Packets: 24 | Duration: 182s | Downloads: 8162 |
EIGRP_adjacency.cap 5.1 KB
Submitted Sep 14, 2009
Formation of an EIGRP adjacency between routers R1 and R2. Capture point is R1's 10.0.0.1 interface.
| Packets: 53 | Duration: 104s | Downloads: 10287 |
EIGRP_goodbye.cap 1.3 KB
Submitted Sep 14, 2009
R2 designates its interface facing R1 as passive. The final hello message from R2 (packet #9) has all its K values set to 255, designating the message as a "goodbye." Capture perspective is from R1's 10.0.0.1 interface.
| Packets: 15 | Duration: 43s | Downloads: 7669 |
EIGRP_subnet_down.cap 1.8 KB
Submitted Sep 14, 2009
R4's interface to 192.168.4.0/24 goes down and the route is advertised as unreachable. Queries are issued by all routers to find a new path to the subnet but none exists, and the route is removed from the topology. Capture perspective is from R1's 10.0.0.1 interface.
| Packets: 21 | Duration: 23s | Downloads: 6065 |
EIGRP_subnet_up.cap 1.3 KB
Submitted Sep 14, 2009
R4's 192.168.4.0/24 subnet is brought online. R1 receives updates from both R2 and R3 (only R2's update is shown in the capture). The poison-reverse in packet #9 informs R2 not to use R1 as a path to 192.168.4.0/24. The capture perspective is from R1's 10.0.0.1 interface.
| Packets: 15 | Duration: 18s | Downloads: 8055 |
EIGRPv2_adjacency.cap 4.1 KB
Submitted Sep 14, 2009
Routers 1 and 2 form an EIGRPv2 adjacency and exchange IPv6 routes.
| Packets: 31 | Duration: 52s | Downloads: 8046 |
EIGRPv2_subnet_transition.cap 5.3 KB
Submitted Sep 14, 2009
R4's 2001:db8:0:400::/64 subnet goes down, then comes back up roughly thirty seconds later. Capture perspective from R1's 2001:db8:0:12::1 interface.
| Packets: 49 | Duration: 65s | Downloads: 6243 |
IBGP_adjacency.cap 2.3 KB
Submitted Sep 14, 2009
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.
| Packets: 17 | Duration: 63s | Downloads: 7940 |
ISIS_external_lsp.cap 17.0 KB
Submitted Sep 14, 2009
R2 floods the external routes redistributed from RIP into area 10. Packet #9 includes the IP external reachability TLV. Capture perspective from R3's 10.0.10.1 interface.
| Packets: 15 | Duration: 23s | Downloads: 6962 |
ISIS_level1_adjacency.cap 27.4 KB
Submitted Sep 14, 2009
Routers 2 and 3 form an IS-IS level 2 adjacency.
| Packets: 22 | Duration: 58s | Downloads: 7950 |
ISIS_level2_adjacency.cap 51.8 KB
Submitted Sep 14, 2009
Routers 3 and 4 form an IS-IS level 2 adjacency.
| Packets: 43 | Duration: 85s | Downloads: 9054 |
ISIS_p2p_adjacency.cap 21.7 KB
Submitted Sep 14, 2009
Routers 1 and 2 form a L1/L2 adjacency over a point-to-point serial link. Note that both levels of adjacency are managed with a point-to-point (P2P) hello.
| Packets: 26 | Duration: 113s | Downloads: 10149 |
LDP_adjacency.cap 5.7 KB
Submitted Sep 14, 2009
PE1 and P1 multicast LDP hellos to 224.0.0.2 on UDP port 646. They then establish an adjacency on TCP port 646 and exchange labels.
| Packets: 61 | Duration: 108s | Downloads: 9751 |
MSDP.cap 4.1 KB
Submitted Sep 14, 2009
R2 and R3 become MSDP peers and exchange keepalives. A multicast source 172.16.40.10 begins sending traffic to group 239.123.123.123, and R2 begins sending periodic source active messages to R3. Capture perspective is the R2-R3 link.
| Packets: 35 | Duration: 391s | Downloads: 6326 |
OSPF_Down-Bit.cap 8.9 KB
Submitted Oct 27, 2009 by colinbsd
LSA Update with down bit set. Router R5 56.0.0.5 PE is receiving an update from the MPLS VPN, which is advertised to CE 56.0.0.6 ospf routing table. In order for for the packet(LSA) not to be re-advertised back into the MPLS cloud through another PE(2) router, PE sets the Down-bit to 1. filter: ospf.v2.options.dn == 1
| Packets: 98 | Duration: 203s | Downloads: 9666 |
OSPF_LSA_types.cap 4.0 KB
Submitted Sep 14, 2009
Capture of adjacency formation between OSPF routers 4 and 5 in area 20. Packet #12 contains LSAs of types 1, 2, 3, 4, and 5.
| Packets: 30 | Duration: 63s | Downloads: 12220 |