Packet Captures
4-byte_AS_numbers_Mixed_Scenario.cap (414 bytes)
| Packets: 4 | Duration: 60s | Downloads: 5313 |
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".
- Categories: Routing Protocols
- Protocols: BGP, HDLC, IP, TCP
4-byte_AS_numbers_Full_Support.cap (1.2 KB)
| Packets: 9 | Duration: 56s | Downloads: 4919 |
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.
- Categories: Routing Protocols
- Protocols: BGP, HDLC, IP, TCP
DECnet_Phone.pcap.cap (7.5 KB)
| Packets: 139 | Duration: 100s | Downloads: 4384 |
A DECnet Phone session, using the Linux DECnet stack and a clone/port of the OpenVMS eponymous tool.
rpvstp-trunk-native-vid5.pcap.cap (1.8 KB)
| Packets: 22 | Duration: 11s | Downloads: 6633 |
Rapid per-VLAN spanning tree capture of a trunk port, configured with native VLAN 5, VLAN 1 is also active over the trunk.
Capture shows that 3 BPDUs are sent out, one for classic STP (Frame 4, for example), one for the native VLAN 5 (not tagged - Frame 5) and one for each other active VLAN (tagged - Frame 3).
The PVST BPDUs contain the VLAN ID at the end of the frame (01 and 05, respectively).
rpvstp-trunk-native-vid1.pcap.cap (6.4 KB)
| Packets: 81 | Duration: 45s | Downloads: 5319 |
Rapid per-VLAN spanning tree capture of a trunk port, configured with native VLAN 1 (default), VLAN 5 is also active over the trunk.
Capture shows that 3 BPDUs are sent out, one for classic STP (Frame 4, for example), one for the native VLAN (not tagged - Frame 3) and one for each other active VLAN (tagged - Frame 5).
The PVST BPDUs contain the VLAN ID at the end of the frame (01 and 05, respectively).
rpvstp-access.pcap.cap (3.7 KB)
| Packets: 49 | Duration: 77s | Downloads: 4757 |
Rapid per-VLAN spanning tree capture of an access port (without portfast), configured in VLAN 5.
Frame-Relay over MPLS.pcap.cap (1.4 KB)
| Packets: 10 | Duration: 1s | Downloads: 5999 |
ICMP on a Frame-relay over MPLS link. If Wireshark doesn't understand it's FR, right click on a packet, select "Decode as" from the menu and select "Frame Relay DLCI PW" on the "MPLS" tab.
EoMPLS_802.1q.pcap.cap (1.6 KB)
| Packets: 10 | Duration: 1s | Downloads: 5882 |
ICMP over EoMPLS with 802.1q tagging
LDP_Ethernet_FrameRelay.pcap.cap (2.1 KB)
| Packets: 14 | Duration: 7s | Downloads: 5216 |
LDP with pseudowire FEC elements (Ethernet and Frame-Relay DLCI-to-DLCI)
BGP_MD5.cap (1.7 KB)
| Packets: 16 | Duration: 61s | Downloads: 5983 |
An EBGP with TCP MD5 authentication enabled
- Categories: Authentication, Routing Protocols
- Protocols: BGP, Ethernet, IP, TCP
PAGP.cap (2.5 KB)
| Packets: 25 | Duration: 95s | Downloads: 4491 |
LACP.cap (2.8 KB)
| Packets: 20 | Duration: 112s | Downloads: 6120 |
BGP_redist.cap (378 bytes)
| Packets: 2 | Duration: n/a | Downloads: 5833 |
The OSPF metric is preserved and propagated within the MPLS cloud by the MP-BGP MED attribute.
OSPF_Down-Bit.cap (8.9 KB)
| Packets: 98 | Duration: 203s | Downloads: 5071 |
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
PPP_negotiation.cap (4.6 KB)
| Packets: 63 | Duration: 67s | Downloads: 5708 |
EoMPLS.cap (7.0 KB)
| Packets: 56 | Duration: 32s | Downloads: 5608 |
Routers at 1.1.2.1 and 1.1.2.2 are PEs in a MPLS cloud. LDP starts at packet 8 and they build up a pseudo-wire VC (last FEC in packets 11 and 13). At packet 15 we already have STP running between CE1 and CE2 (two routers with ESW), encapsulated in 2 MPLS headers. All the ethernet stuff follows: CDP, ARP, ICMP between two hosts on the same subnet.
DHCP_Inter_VLAN.cap (2.0 KB)
| Packets: 4 | Duration: n/a | Downloads: 5353 |
R1 is a router-on-a-stick. It receives a DHCP Discover on the trunk interface, it sets the "Relay agent IP address" to the sub-interface's IP address it received the packet on and, finally, it forwards it to the DHCP server. Capture perspective is R1-DHCP server link.
PIM_register_register-stop.cap (258 bytes)
| Packets: 2 | Duration: n/a | Downloads: 4900 |
Switch at 192.168.0.6 receives an IGMP request for the group 239.1.2.3, encapsulates the original IGMP packet in a PIM Register and sends it to the RP at 192.168.1.254. In packet #2 RP sends a Register-Stop to the switch.
DHCP.cap (5.8 KB)
| Packets: 12 | Duration: 153s | Downloads: 6649 |
R0 is the client and R1 is the DHCP server. Lease time is 1 minute.
VRRP_preempt.cap (1.2 KB)
| Packets: 16 | Duration: 14s | Downloads: 4632 |
Initially R3 is the master, R2 is backup, and R1 is offline. R1 comes back online with a priority of 200, preempting R3 to become the master router.
- Categories: Redundancy
- Protocols: Ethernet, IP, VRRP
VRRP_failover.cap (2.4 KB)
| Packets: 32 | Duration: 33s | Downloads: 5575 |
The master router (R1) goes offline. After the down interval passes (roughly 3 seconds), R3 takes over as the master router in packet #12. R2 also offers to take over but R3 wins because it has the higher IP address.
- Categories: Redundancy
- Protocols: Ethernet, IP, VRRP
UDLD.cap (3.3 KB)
| Packets: 29 | Duration: 93s | Downloads: 4661 |
Unidirectional Link Detection (UDLD) is used to monitor the status of a link between a Catalyst 2960 and a Catalyst 3560. Note that echos are initially sent at very small intervals, gradually throttling back to the configured interval of 15 seconds.
- Categories: Cisco-proprietary, Switching
- Protocols: Ethernet, LLC, UDLD
telnet.cap (9.4 KB)
| Packets: 74 | Duration: 10s | Downloads: 5220 |
Telnetting from one router to another. Note that all communication is visible in clear text.
- Categories: Management
- Protocols: Ethernet, IP, TCP, Telnet
TDP.cap (2.8 KB)
| Packets: 33 | Duration: 47s | Downloads: 3289 |
P2 and PE2 exchange Tag Distribution Protocol hellos and form an adjacency over TCP port 711.
SSHv2.cap (11.4 KB)
| Packets: 90 | Duration: 7s | Downloads: 4661 |
An SSH version 2 session between two routers. All communication is securely encrypted.
- Categories: Encryption, Management
- Protocols: Ethernet, IP, SSH, TCP
SNMPv2c_get_requests.cap (894 bytes)
| Packets: 8 | Duration: n/a | Downloads: 3741 |
SNMPv2c get requests are issued from a manager to an SNMP agent in order to monitor the bandwidth utilization of an interface.
- Categories: Management
- Protocols: Ethernet, IP, SNMP, UDP
RIPv2_subnet_down.cap (1.3 KB)
| Packets: 10 | Duration: 86s | Downloads: 3793 |
RIPv2 routes are being flooded on the R1-R2 link. R2's connection to 192.168.2.0/24 goes down, and the route is advertised as unreachable (metric 16) in packet #7. Capture perspective from R1's 10.0.0.1 interface.
- Categories: Routing Protocols
- Protocols: Ethernet, IP, RIP, UDP
RIPv2.cap (1.7 KB)
| Packets: 12 | Duration: 141s | Downloads: 4250 |
A RIPv2 router periodically flooding its database. Capture perspective from R1's 10.0.0.1 interface.
- Categories: Routing Protocols
- Protocols: Ethernet, IP, RIP, UDP
RIPv1_subnet_down.cap (1.0 KB)
| Packets: 8 | Duration: 58s | Downloads: 3151 |
RIPv1 routes are being flooded on the R1-R2 link. R2's connection to 192.168.2.0/24 goes down, and the route is advertised as unreachable (metric 16) in packet #5. Capture perspective from R1's 10.0.1.1 interface.
- Categories: Routing Protocols
- Protocols: Ethernet, IP, RIP, UDP