Command Manual (For Soliton) – MSTP
H3C S3100 Series Ethernet Switches
Chapter 1 MSTP Configuration Commands
1-39
designated port and the port turns to the discarding state, that is, the port does not
forward packets and thereby loops can be prevented.
Examples
# Enable the loop guard function on Ethernet 1/0/1.
<Sysname> system-view
System View: return to User View with Ctrl+Z.
[Sysname] interface Ethernet 1/0/1
[Sysname-Ethernet1/0/1] stp loop-protection
1.1.34 stp max-hops
Syntax
stp max-hops
hops
undo stp
max-hops
View
System view
Parameters
hops
: Maximum hop count to be set. This argument ranges from 1 to 40.
Description
Use the
stp max-hops
command to set the maximum hop count for the MST region the
current switch belongs to.
Use the
undo stp max-hops
command to restore the maximum hop count to the
default.
By default, the maximum hop count of an MST region is 20.
The maximum hop count configured on the region roots of an MST region limits the size
of the MST region.
A configuration BPDU contains a field that maintains the remaining hops of the
configuration BPDU. And a switch discards the configuration BPDUs whose remaining
hops are 0. After a configuration BPDU reaches a root bridge of a spanning tree in a
MST region, the value of the remaining hops field in the configuration BPDU is
decreased by 1 every time the configuration BPDU passes one switch. Such a
mechanism disables the switches that are beyond the maximum hops from
participating in spanning tree calculation, and thus limits the size of an MST region.
With such a mechanism, the maximum hops configured on the switch operating as the
root bridge of the CIST or an MSTI in a MST region becomes the network diameter of
the spanning tree, which limits the size of the spanning tree in the current MST region.
