3Com S7906E Command Reference Manual page 141

Parameters
number: Service loopback group ID. The value range for the number argument is 1 to 1,024..
type: Specifies the service type of a service loopback group.
tunnel: Specifies the service type of a service loopback group as Tunnel.
multicast-tunnel: Specifies the service type of a service loopback group as Multicast tunnel.
Description
Use the service-loopback group command to create a service loopback group or change the service
type of an existing service loopback group.
Use the undo service-loopback group command to remove a service loopback group.
Note that:
A service loopback group can be referenced by other features after its creation. Only after being
referenced can a service loopback group process service traffic. A service loopback group can be
referenced by multiple features at the same time.
You can change the service type of an existing service loopback group. For the change to be
successful, you must ensure that the service group has not been referenced; the attributes of all
member ports (if any) are not conflicting with the target service type; and no service loopback group
has been created for the target service type, because only one service loopback group is allowed
for a service type.
You can remove any service loopback group except the referenced ones.
Examples
# Configure service loopback group 1 to support the tunnel service.
<Sysname> system-view
[Sysname] service-loopback group 1 type tunnel
1-3