Switch 7700 Command reference Guide, v2.0

312 CHAPTER 8: USING STP COMMANDS
View
Ethernet port view
Parameter
None
Description
Using the stp root-protection command, you can enable Root protection
function on a switch. Using the
undo stp root-protection command, you can
restore the default status of Root protection function.
By default, Root protection is not enabled.
Due to configuration error of the maintenance personnel or malicious user attack,
a legal root of the network may receive a BPDU with higher priority and lose its
status as a root, which causes unpleasant changes of network topology. Such
illegal changes may pull the higher-speed traffic to lower-speed links and cause
network congestion.
To avoid such problem, RSTP provides Root protection function. After being
configured with Root protection, a port always stays as a designated port. Once
such port receives a BPDU with higher priority, it turns to listening status and will
not forward any packets (as if the link to it is disconnected). It will resume normal
status if it receives no BPDU with higher-priority for a period of time.
Example
Enable Root protection function on Ethernet1/0/1 of the switch.
[SW7700-Ethernet1/0/1]stp root-protection
stp timeout-factor Syntax
stp timeout-factor number
undo stp timeout-factor
View
System view
Parameter
number: Specifies the multiple of hello time, ranging from 3 to 7.
Description
Using stp timeout-factor command, you can configure multiple of hello time
for the switch. Using
undo stp timeout-factor command, you can restore the
default multiple value.
By default, the multiple is 3.
The Ethernet switch transmits RSTP packets every hello time. Generally, if the
switch doesn’t receive the RSTP packets from the upstream switch for 3 times of
hello time, the switch will decide the upstream switch is dead and will recalculate
the topology of the network. Then in steady network, the recalculation may be
caused when the upstream is busy. In this case, user can redefine the timeout