XS26GS Managed Optical Ethernet Switch User Manual
139
XS#
spanning-tree forward-time
17
Configure successfully
spanning-tree hello-time
Syntax
spanning-tree hello-time
timer-value
no spanning-tree hello-time
View
System view
Parameters
timer-value
: hello time in seconds to be set. This argument ranges from 1 to 10. The
default value is 2 seconds.
Description
Use
spanning-tree hello-time
command to set the hello time.
Use
no spanning-tree hello-time
command to restore the hello time to the
default value.
By default, the hello time is 2 seconds.
A root bridge regularly sends out configuration BPDUs to maintain the stability of
existing spanning trees. If the switch does not receive a BPDU packet in a specified
period, spanning trees will be recalculated when BPDU packet times out. When a
switch becomes a root bridge, it regularly sends BPDUs at the interval specified by
the hello time you have configured on it. The other none-root-bridge switches adopt
the interval specified by the hello time.
As for the configuration of the three time-related parameters (hello time, forward
delay, and max age), the following formula must be met to prevent network jitter.
z
2 × (forward delay – 1 second) >= max age
z
Max age >= 2 × (hello time + 1 second)
Examples
XS#
spanning-tree hello-time
3
Configure successfully.
spanning-tree max-age
Syntax
spanning-tree max-age
timer-value
no spanning-tree max-age
View
System view
Parameters
timer-value
: max age to be set, in a range from 6 to 40 (seconds). The default value
is 20 seconds.