Huawei Quidway S3000 Series Operation Manual page 49

Operation Manual - STP
Quidway S3000 Series Ethernet Switches
high-speed link may be pulled to the low-speed link and congestion will occur on the
network. Root protection function is used against such problem.
The root port and other blocked ports maintain their state according to the BPDUs send
by uplink switch. Once the link is blocked or has trouble, then the ports cannot receive
BPDUs and the switch will select root port again. In this case, the former root port will
turn into specified port and the former blocked ports will enter forwarding state, as a
result, a link loop will be generated.
The security functions can control the generation of loop. After it is enabled, the root
port cannot be changed, the blocked port will maintain in "Discarding" state and do not
forward packets, thus to avoid link loop.
You can use the following command to configure the security functions of the switch.
Perform the following configuration in corresponding configuration modes.
Table2-22 Configure the switch security function
Configure switch BPDU protection (from system view)
Restore the disabled BPDU protection state as defaulted
(from system view)
Configure switch Root protection (from system view)
Restore the disabled Root protection state as defaulted
(from system view)
Configure switch Root protection (from Ethernet port view)
Restore the disabled Root protection state as defaulted
(from Ethernet port view)
Configure switch loop protection function (from Ethernet port
view)
Restore the disabled loop protection state, as defaulted
(from Ethernet port view)
After configured with BPDU protection, the switch will disable the edge port through
MSTP, which receives a BPDU, and notify the network manager at same time. These
ports can be resumed by the network manager only.
The port configured with Root protection only plays a role of designated port on every
instance. Whenever such port receives a higher-priority BPDU, that is, it is about to turn
into non-designated port, it will be set to listening state and not forward packets any
more (as if the link to the port is disconnected). If the port has not received any
higher-priority BPDU for a certain period of time thereafter, it will resume the normal
state.
When configure a port, only one configuration can be effective among loop protection,
Root protection and Edge port configuration at same moment.
Operation
2-25
Chapter 1 RSTP Configuration
Command
stp bpdu-protection
undo stp bpdu-protection
stp interface interface-list
root-protection
undo stp interface interface-list
root-protection
stp root-protection
undo stp root-protection
stp loop-protection
stp loop-protection