Switch 7700 Command reference Guide, v2.0

MSTP Configuration Commands 323
Parameter
None
Description
■ Use the stp bpdu-protection command to enable the BPDU protection on
the switch.
■ Use the undo stp bpdu-protection command to restore the default state of
BPDU protection.
By default, BPDU protection is disabled.
Generally, the access ports of the access layer devices are directly connected to
user terminals (such as PC) or file servers. In this case, the access ports are set to
edge ports to implement fast state transition. However, when such access ports
receive configuration BPDU, the system will automatically set them to non-edge
ports and recalculate the spanning tree, which makes the network topology flap.
These ports will not receive any STP configuration BPDU in normal cases. Anyway,
if someone maliciously attacks the switch with fake configuration BPDU, the
network will flap.
MSTP provides BPDU protection function to avoid such attack: 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.
Example
Enable BPDU protection on the switch.
[SW7700]stp bpdu-protection
stp bridge-diameter Syntax
stp bridge-diameter bridgenum
undo stp bridge-diameter
View
System view
Parameter
bridgenum: Ranges from 2 to 7 and defaults to 7.
Description
■ Use the stp bridge-diameter command to configure the switching network
diameter.
■ Use the undo stp bridge-diameter command to restore the default network
diameter.
The network diameter refers to the maximum count of switches on the path
between any two terminal devices. The definition of network diameter is the
maximum count of switches between the farthest communication ends.