3Com 10014299 Debugging GRE, GRE Configuration Example, All views, Application of IP-over-IP

Displaying and Debugging GRE 641

Disable tunnel interface to synchronize sequence numbers.

undo gre sequence-datagrams

By default, the tunnel interface to synchronize datagram sequence numbers is disabled.

Displaying and	To view the working status of the tunnel interface, use the display command in
Debugging GRE	all views.
	Table 694 Display and Debug GRE
	Operation	Command
	Display the working status of tunnel	display interfaces tunnel [
	interface.	tunnel-number ]
GRE Configuration
Example
Application of IP-over-IP	VPN should be built across the WAN for the operation of Novell IPX's two subnets
GRE	group1 and group2. It can be implemented by using GRE.

PC A communicates with PC B in GRE tunneling mode in the Internet. Router A and Router B are two ends of the GRE tunnel, while Router C is located in the GRE tunnel.

Figure 204 Networking diagram of GRE application

	10.1.1.1	10.1.1.2	20.1.1.1	20.1.1.2
Router A		Router C			Router B
E0	S0	S0	S1	S0	E0
PC A		Internet			PC B
10.110.24.100		tunnel			30.110.1.200
10.110.24.1					30.110.1.1

1Configure PC A and PC B:

aConfigure the IP address of PC_A to 10.110.24.100, add a default gateway in the network attribute (i.e., default route), or use the following command in DOS mode.

C:\WINDOWS> route add 0.0.0.0 mask 0.0.0.0 10.110.24.1

bConfigure the IP address of PC_B to 30.110.1.200, add a default gateway in the network attribute (i.e., default route), or use the following command in DOS mode.

C:\WINDOWS> route add 0.0.0.0 mask 0.0.0.0 30.110.1.1

2Configure Router A:

aConfigure the IP address of Serial0 interface.

[RouterA] interface serial 0

[RouterA-Serial0]ip address 10.1.1.1 255.255.255.0