Panasonic NN46240-710 - Manual (Page 62)

2 GRE troubleshooting
Nortel Secure Router 8000 Series
_________ Troubleshooting - VPN
2.2.4 Troubleshooting procedure
This section provides the troubleshooting steps.
Two different situations are possible.
Network layer protocol of one end or both ends of the tunnel interface is down
Step 1 Check that both ends of the tunnel use a consistent encapsulation type.
Run the display this interface command in the tunnel interface view to check the
encapsulation type. View the display of the tunnel interface to find the encapsulation type on
both ends of the tunnel. The sample display is as follows:
[Nortel1-Tunnel1/0/0] display this interface
Tunnel1/0/0 current state : UP
Line protocol current state : UP
Description : Nortel Series, Tunnel1/0/0 Interface, Route Port
The Maximum Transmit Unit is 1500 bytes
Internet Address is 30.1.1.1/24
Encapsulation is TUNNEL, loopback not set
Tunnel source 100.1.1.1 (Serial1/0/0), destination 100.2.1.2
Tunnel protocol/transport GRE/IP , key disabled
Checksumming of packets disabled
QoS max-bandwidth : 64 Kbps
Output queue : (Urgent queue : Size/Length/Discards) 0/50/0
Output queue : (Protocol queue : Size/Length/Discards) 0/1000/0
Output queue : (FIFO queuing : Size/Length/Discards) 0/75/0
5 minutes input rate 0 bytes/sec, 0 packets/sec
5 minutes output rate 0 bytes/sec, 0 packets/sec
0 packets input, 0 bytes
0 input error
0 packets output, 0 bytes
0 output error
The tunnel currently supports three types of encapsulation:
• GRE (default type)
• IPv6-IPv4
• Multiprotocol Label Switching (MPLS) Traffic Engineering (TE)
You can find that the tunnel uses GRE encapsulation by viewing the information in boldface in
the display.
If the same encapsulation type is set at both ends, go to step 2.
Step 2 Check that IP addresses, source addresses, and destination addresses are correct on the tunnel
interfaces on both ends.
The source address of one end is the destination address of another end and the destination
address of one end is the source address of another end. Otherwise, a tunnel cannot establish
because a source and a destination address together identify a unique tunnel.
Run the display this command in the tunnel interface view to check the configuration at both
ends of the tunnel.
For example, the correct tunnel configuration for Figure 2-3 is as follows:
2-8 Nortel Networks Inc. Issue 5.3 (30 March2009)