H3C Technologies H3C SecPath F1000-E - Manual (Page 7)

6
To do… Use the command… Remarks
Configure the key for the GRE
tunnel interface
gre key key-number
Optional
By default, no key is configured for
a GRE tunnel interface.
The two ends of a tunnel must have
the same key or have no key at the
same time.
Configure a route for packet
forwarding through the tunnel
See the IP Routing Volume.
Required
Each end of the tunnel must have a
route (static or dynamic) through
the tunnel to the other end.
Note that:
• For more information about tunnel interfaces and more configuration commands in a tunnel
interface, see Tunneling Configuration in the IP Services Volume.
• For information about commands interface tunnel, tunnel-protocol, source, and
destination, see Tunneling Commands in the IP Services Volume.
• The source address and destination address of a tunnel uniquely identify a path. They must be
configured at both ends of the tunnel and the source address at one end must be the destination
address at the other end and vice versa.
• Tunnel interfaces using the same encapsulation protocol must have different source addresses and
destination addresses.
• If you configure a source interface for a tunnel interface, the tunnel interface takes the primary IP
address of the source interface as its source address.
• You can enable or disable the checksum function at both ends of the tunnel as needed. If the
checksum function is enabled at the local end but not at the remote end, the local end calculates the
checksum of a packet to be sent but does not check the checksum of a received packet. Contrarily,
if the checksum function is enabled at the remote end but not at the local end, the local end checks
the checksum of a received packet but does not calculate the checksum of a packet to be sent.
• When configuring a route through the tunnel, you can configure a static route, using the address of
the network segment that the original packet is destined for as its destination address and the
address of the peer tunnel interface as its next hop. Or, you can enable a dynamic routing protocol
on both the tunnel interface and the device interface connecting the private network, so that the
dynamic routing protocol can establish a routing entry that allows the tunnel to forward packets
through the tunnel. It is not allowed to set up a static route whose destination address is in the subnet
of the tunnel interface.
Configuring a GRE over IPv6 Tunnel
Configuration Prerequisites
On each of the peer devices, configure an IP address for the interface to be used as the source interface
of the tunnel interface (which can be a, for example, VLAN interface, GigabitEthernet interface, or
loopback interface), and make sure that this interface can normally communicate with the interface used
as the source interface of the tunnel interface on the peer device.