HP A6600 Configuration Manual page 80

• Root guard
• Loop guard
• TC-BPDU guard
• BPDU drop
Configuration prerequisites
MSTP has been correctly configured on the device.
Enabling BPDU guard
For access layer devices, the access ports generally connect directly with user terminals (such as PCs) or
file servers. In this case, the access ports are configured as edge ports to allow rapid transition. When
these ports receive configuration BPDUs, the system automatically sets these ports as non-edge ports and
starts a new spanning tree calculation process. This causes a change of network topology. Under normal
conditions, these ports should not receive configuration BPDUs. However, if someone forges configuration
BPDUs maliciously to attack the devices, the network becomes instable.
MSTP provides the BPDU guard function to protect the system against such attacks. With the BPDU guard
function enabled on the devices, when edge ports receive configuration BPDUs, MSTP closes these ports
and notifies the NMS that these ports have been closed by MSTP. Those ports closed thereby are
re-activated by the device after a detection interval. For more information about this detection interval,
see Fundamentals Configuration Guide.
Make this configuration on a device with edge ports configured.
To enable BPDU guard:
To do...
1. Enter system view
2. Enable the BPDU guard
function for the device
BPDU guard does not take effect on loopback test-enabled ports. For more information about loopback
test, see Interface Configuration Guide.
Enabling Root guard
The root bridge and secondary root bridge of a spanning tree should be located in the same MST region.
Especially for the CIST, the root bridge and secondary root bridge are generally put in a high-bandwidth
core region during network design. However, due to possible configuration errors or malicious attacks in
the network, the legal root bridge may receive a configuration BPDU with a higher priority. In this case,
the current legal root bridge is superseded by another device, causing an undesired change of the
network topology. As a result, the traffic that should go over high-speed links is switched to low-speed
links, resulting in network congestion.
To prevent this situation from happening, MSTP provides the root guard function. If the root guard
function is enabled on a port of a root bridge, this port keeps playing the role of designated port on all
MSTIs. Once this port receives a configuration BPDU with a higher priority from an MSTI, it immediately
sets that port to the listening state in the MSTI, without forwarding the packet (this is equivalent to
disconnecting the link connected with this port in the MSTI). If the port receives no BPDUs with a higher
priority within twice the forwarding delay, it reverts to its original state.
Make this configuration on a designated port.
Use the command...
system-view
stp bpdu-protection
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Remarks
—
Required
Disabled by default