3com MSR 20-20 참조 매뉴얼

Use the undo keepalive command to disable the keepalive function.

By default, the GRE keepalive function is disabled.

With the GRE keepalive function enabled on a tunnel interface, the device sends 
GRE keepalive packets from the tunnel interface periodically. If no response is 
received from the peer within the specified interval, the device retransmits a 
keepalive packet. If the device still receives no response from the peer after a 
keepalive packet is transmitted for the maximum number of attempts, the local 
tunnel interface goes down and keeps down until it receives a keepalive 
acknowledgement packet from the peer.

# Set the GRE keepalive interval to 20 seconds and the maximum number of 
attempts for transmitting a keepalive packet to 5.

<Sysname> system-view

[Sysname] interface tunnel 0

[Sysname-Tunnel0] keepalive 20 5 

source { ip-address | ipv6-address | interface-type interface-number }

Tunnel interface view

ip-address: Source IPv4 address for a tunnel interface.

Ipv6-address: Source IPv6 address for a tunnel interface.

interface-type interface-number: Type and number of the source interface for a 
tunnel interface. The interface type can be Ethernet, VLAN, serial, ATM, tunnel, or 
loopback.

Use the source command to specify the source address or interface for a tunnel 
interface.

Use the undo source command to remove the configuration.

By default, no source address or interface is configured for a tunnel interface.

Note that:

■

The source address of a tunnel interface is the address of the interface sending 
GRE packets and is usually the destination address of the peer tunnel interface.

■

Two or more tunnel interfaces using the same encapsulation protocol must 
have different source addresses and destination addresses.