3Com Switch 8800 Family IPsec Module Configuration and Command reference Guide

GRE Configuration 133
actual physical interface forwarding GRE packets, thus improving the forwarding
efficiency.
Setting Encapsulation
Mode
Encapsulation protocol and delivery protocol are to be configured on Tunnel
interface. You may choose not to configure them on both ends of the Tunnel, but
if you do configure them, make sure to use the same encapsulation mode on both
ends (by far, only GRE is available).
Perform the following configuration in Tunnel interface view.
By default, encapsulation protocol is GRE, and delivery protocol is IP.
Specifying Tunnel
Source
After the creation of a Tunnel interface, the source address of the Tunnel, that is,
the actual interface address where GRE packets are forwarded also needs to be
specified. A Tunnel is uniquely identified by one source address and one
destination address. These configurations are required on both ends of the Tunnel,
with the source address at one end being the destination address at the other end
and vice versa.
Perform the following configuration in Tunnel interface view.
n
■ The same source address and destination address cannot be configured on two
or more Tunnel interfaces encapsulated with the same protocol.
■ The source command configures actual physical interface address or actual
physical interface. The network address of Tunnel interface also needs
configuring by using the ip address command in Tunnel interface view.
Specifying Tunnel
Destination
After the creation of a Tunnel interface, the destination address of the Tunnel, that
is, IP address of the actual physical interface receiving GRE packets, also needs to
be specified. A Tunnel is uniquely identified by one source address and one
destination address. These configurations are required on both ends of the Tunnel,
with the source address at one end being the destination address at the other end
and vice versa.
Perform the following configuration in Tunnel interface view.
Tab le 119 Set encapsulation mode
Operation Command
Set encapsulation mode on the Tunnel interface tunnel-protocol gre
Delete the encapsulation mode on the Tunnel interface undo tunnel-protocol
Tab le 120 Specify source address of the Tunnel
Operation Command
Specify source address of the Tunnel source { ip-addr | interface-type interface-num }
Delete the source address of the Tunnel undo source