HP A6600 Configuration Manual page 81

To enable root guard:
To do...
1. Enter system view
2. Enter
interface
view or port
group view
3. Enable the root guard function for the
ports
Among loop guard, root guard and edge port settings, only one function (whichever is configured the
earliest) can take effect on a port at the same time.
Enabling Loop guard
By keeping receiving BPDUs from the upstream device, a device can maintain the state of the root port
and blocked ports. However, due to link congestion or unidirectional link failures, these ports may fail to
receive BPDUs from the upstream devices. In this case, the device reselects the port roles: Those ports in
forwarding state that failed to receive upstream BPDUs become designated ports, and the blocked ports
transition to the forwarding state, resulting in loops in the switched network. The loop guard function can
suppress the occurrence of such loops.
The initial state of a loop guard-enabled port is discarding in every MSTI. When the port receives BPDUs,
the state transition is normal. Otherwise, it stays in the discarding state, thus avoiding the occurrence of
loops.
Make this configuration on the root port and alternate ports of a device.
To enable loop guard:
To do...
1. Enter system view
2. Enter
interface
view or port
group view
3. Enable the loop guard function for the ports
Do not enable loop guard on a port connecting user terminals. Otherwise, the port stays in the discarding
state in all MSTIs because it cannot receive BPDUs.
Among loop guard, root guard and edge port settings, only one function (whichever is configured the
earliest) can take effect on a port at the same time.
Enabling TC-BPDU guard
When receiving TC BPDUs (the BPDUs used to notify topology changes), a switch flushes its forwarding
address entries. If someone forges TC-BPDUs to attack the switch, the switch receives a large number of
TC-BPDUs within a short time and is busy with forwarding address entry flushing. This affects network
stability.
Enter Ethernet interface
view, or Layer 2
aggregate interface view
Enter port group view
Enter Ethernet interface view,
or Layer 2 aggregate
interface view
Enter port group view
Use the command...
system-view
interface interface-type
interface-number
port-group manual
port-group-name
stp root-protection
Use the command...
system-view
interface interface-type
interface-number
port-group manual
port-group-name
stp loop-protection
74
Remarks
—
Required.
Use either command.
Required.
Disabled by default.
Remarks
—
Required.
Use either command.
Required.
Disabled by default.