- Nortel VPN Router Troubleshooting

106 Chapter 5 Packet capture
NN46110-602
Capture types
The VPN Router captures packets from the following sources:
• Physical interfaces, including the following:
— Asynchronous digital subscriber line (ADSL)/asynchronous transfer
mode (ATM)
— Fast Ethernet and Gigabit Ethernet, including traffic that is not directed to
the VPN Router (promiscuous mode)
— Dial (V.90 and asynchronous Point-to-Point Protocol [PPP])
— Integrated services digital network basic-rate interface (ISDN BRI)
—Serial
• Tunnels
— Branch offices (all types)
—User tunnels
• All IP traffic on the VPN Router
The following sections describe each type of capture.
Physical interface captures
Packet capture of traffic on a physical interface can help you troubleshoot
Layer 2 issues, connectivity issues, and performance issues. The Layer 2 header is
saved in the PCAP file for each packet. You can convert PCAP files containing
traffic captured on a physical interface to most file formats, including Network
General Sniffer.
Tunnel captures
You can use packet capture of traffic over tunnels to help troubleshoot a specific
tunnel problem. For example, you can create a tunnel capture object to diagnose
the following types of problems:
• a protocol not working for a particular user
• performance issues for a particular user
• Open Shortest Path First (OSPF) not working properly inside a specific
branch office tunnel