Configuring mGRE

Set the tunnel interface type to mGRE, so that multiple GRE tunnels can be established on a tunnel interface, simplifying the configuration.

Context

To implement DSVPN, create a tunnel interface and set the tunnel type to mGRE. You only need to configure the source address or source interface for the mGRE tunnel interface, but do not need to specify a destination address. Then multiple GRE tunnels can be established on the mGRE tunnel interface and correspond to multiple GRE peers, simplifying GRE configuration.

Perform the following configurations on the spokes and hub.

Procedure

Run system-view
The system view is displayed.
Run interface tunnel interface-number
A tunnel interface is created, and the tunnel interface view is displayed.
Run ip address ip-address { mask | mask-length }
An IP address is assigned to the tunnel interface.
Run tunnel-protocol gre p2mp
The tunnel encapsulation mode is set to mGRE.

The mGRE tunnels can be configured only on one-dimensional tunnel interfaces.

Modifying the tunnel encapsulation mode will delete the configured parameters of the tunnel interface, including the source address or source interface of the tunnel interface and NHRP parameters.
Run source { ip-address | ifName | ifType ifNum }
The source IP address or interface is specified for the tunnel.
(Optional) Run gre key { simple key-number-simple | [ cipher ] key-number-cipher }
A key that identifies a tunnel is set.

If multiple mGRE tunnel interfaces use the same source address or source interface, you must configure a particular key for each mGRE tunnel.

If simple is specified, the key is saved in the configuration file in simple text, posing security risks. You are advised to select cipher to save the key in ciphertext in the configuration file.
Run commit
The configuration is committed.