H3C Technologies H3C S12500 Series Switches - Manual (Page 241)

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• 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.
• When configuring a route through the tunnel, you are not allowed to set up a static route whose
destination address is in the subnet of the tunnel interface. Instead, you can do one of the following:
{
Configure a static route, using the address of the subnet that the original packet is destined for
as its destination address and the address of the peer tunnel interface as its next hop.
{
Enable a dynamic routing protocol on both the tunnel interface and the router 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.
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, Ethernet interface, or loopback
interface), and make sure that this interface can correctly communicate with the interface used as the
source interface of the tunnel interface on the peer device.
Configuration procedure
To configure a GRE over IPv4 tunnel:
Step Command Remarks
1. Enter system view. system-view N/A
2. Create a tunnel interface and
enter tunnel interface view.
interface tunnel interface-number
By default, the switch has no tunnel
interface.
3. Configure an IPv4 address for
the tunnel interface. ip address ip-address { mask |
mask-length } By default, a tunnel interface has
no IPv4 address.
4. Set the tunnel mode to GRE
over IPv4.
tunnel-protocol gre
Optional.
The default tunnel mode is GRE
over IPv4.
You must configure the same tunnel
mode on both ends of a tunnel.
Otherwise, packet delivery will
fail.
5. Configure the source address
or interface for the tunnel
interface.
source { ip-address | interface-type
interface-number }
By default, no source address or
interface is configured for a tunnel
interface.
6. Configure the destination
address for the tunnel
interface. destination ip-address
By default, no destination address
is configured for a tunnel interface.
7. Configure a route to direct
traffic to the tunnel. See Layer 3—IP Routing
Configuration Guide.
Each end of the tunnel must have a
route (static or dynamic) through
the tunnel to the other end.