H3C Technologies H3C S3100 Series Switches - Manual (Page 190)

Operation Manual – MSTP
H3C S3100-52P Ethernet Switch
Chapter 1 MSTP Configuration
1-15
I. Configuration procedure
Table 1-8 Configure the MSTP operation mode
Operation Command Description
Enter system view system-view —
Configure the MSTP
operation mode stp mode { stp | rstp |
mstp }
Required
An MSTP-enabled switch
operates in the MSTP
mode by default.
II. Configuration example
# Configure the current MSTP-enabled switch to operate in the STP-compatible mode.
system-view
[H3C] stp mode stp
1.2.7 Configuring the Maximum Hops of MST Region
The maximum hops configured on the region root is also the maximum hops of an MST
region. The value of the maximum hops 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 an
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 an MST region becomes the network diameter of
the spanning tree, which limits the size of the spanning tree in the current MST region.
The switches that are not root bridges in the MST region adopt the maximum hop
settings of their root bridges.
I. Configuration procedure
Table 1-9 Configure the maximum hops for an MST region
Operation Command Description
Enter system view system-view —
Configure the maximum
hops of the MST region
stp max-hops
hops
Required
By default, the maximum hops of
an MST region are 20.