GRE commands -- gre checksum

Use gre checksum to enable GRE checksum.

Use undo gre checksum to disable GRE checksum.

Syntax

gre checksum

undo gre checksum

Default

GRE checksum is disabled.

Views

Tunnel interface view

Predefined user roles

network-admin

mdc-admin

Usage guidelines

GRE checksum verifies packet integrity.

You can enable or disable GRE checksum at each end of a tunnel as needed. After GRE checksum is enabled, the sender does the following:

· Calculates the checksum for the GRE header and the payload.

· Sends the packet containing the checksum information to the peer.

The receiver calculates the checksum for the received packet and compares it with that carried in the packet. If the checksums are the same, the receiver processes the packet. If the checksums are different, the receiver discards the packet.

If a packet carries a GRE checksum, the receiver checks the checksum whether or not the receiver is enabled with GRE checksum.

Examples

# Enable GRE checksum.

<Sysname> system-view

[Sysname] interface tunnel 2 mode gre

[Sysname-Tunnel2] gre checksum

GRE commands -- gre key

Use gre key to configure a key for a GRE tunnel interface.

Use undo gre key to restore the default.

Syntax

gre key key

undo gre key

Default

No key is configured for a GRE tunnel interface.

Views

Tunnel interface view

Predefined user roles

network-admin

mdc-admin

Parameters

key: Specifies the key for the GRE tunnel interface, in the range of 0 to 4294967295.

Usage guidelines

You can configure a GRE key to check for the validity of packets received on a GRE tunnel interface.

When a GRE key is configured, the sender puts the GRE key into each sent packet. The receiver compares the GRE key in the received packet with its own GRE key. If the two keys are the same, the receiver accepts the packet. If the two keys are different, the receiver drops the packet.

Both ends of a GRE tunnel must have the same key or no key.

Examples

# Configure the GRE key as 123 for the GRE tunnel interface Tunnel 2.

<Sysname> system-view

[Sysname] interface tunnel 2 mode gre

[Sysname-Tunnel2] gre key 123

GRE commands -- keepalive

Use keepalive to enable GRE keepalive and set the keepalive interval and the keepalive number.

Use undo keepalive to disable GRE keepalive.

Syntax

keepalive [ interval [ times ] ]

undo keepalive

Default

GRE keepalive is disabled.

Views

Tunnel interface view

Predefined user roles

network-admin

mdc-admin

Parameters

interval: Specifies the keepalive interval in the range of 1 to 32767 seconds. The default value is 10.

times: Specifies the keepalive number in the range of 1 to 255. The default value is 3.

Usage guidelines

This command enables the tunnel interface to send keepalive packets at the specified interval. If the device receives no response from the peer within the timeout time, it shuts down the local tunnel interface. The device brings the local tunnel interface up if it receives a keepalive acknowledgment packet from the peer. The timeout time is the result of multiplying the keepalive interval by the keepalive number.

The device always acknowledges the keepalive packets it receives whether or not GRE keepalive is enabled.

GRE/IPv6 mode tunnel interfaces do not support this command.

Examples

# Enable GRE keepalive, set the keepalive interval to 20 seconds, and set the keepalive number to 5.

<Sysname> system-view

[Sysname] interface tunnel 2 mode gre

[Sysname-Tunnel2] keepalive 20 5