Stp Bpdu-Protection; Stp Bridge-Diameter - 3Com 8807 Command Reference Manual

180 C 13: MSTP C C
HAPTER ONFIGURATION OMMANDS

stp bpdu-protection

Syntax
stp bpdu-protection
undo stp bpdu-protection
View
System view
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.
<SW8800>system-view
System View: return to User View with Ctrl+Z
[SW8800] 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.