KBC Networks ESML8P-PC2 - Manual (Page 63)

Manual-ESML8P-PC2_Series-Rev1211
Copyright © KBC Networks Ltd.
Page 63 of 110 www.kbcnetworks.com
5.2.17 Rapid Spanning Tree
The Rapid Spanning Tree Protocol (RSTP) is an evolution of the Spanning Tree Protocol providing
for faster spanning tree convergence after a topology change. The system also supports STP and
will auto-detect the connected device running STP or RSTP.
RSTP System Configuration
This tab allows users to configure parameters for RSTP and displays the spanning tree
information of the root bridge.
• RSTP mode: Click the pull-down menu to enable the RSTP function.
• Priority (0-61440): The switch with the lowest numerical value has the highest priority and
will be selected as the root device. If the value is changed, users must reboot the switch.
Note the value specified in this field must be a multiple of 4096 according to the protocol
rule.
• Max Age (6-40): Enter the time in seconds between 6 and 40 for which the switch waits to
attempt to save its configuration.
• Hello Time (1-10): Enter the time in seconds between 1 and 10 that controls the switch to
send out the BPDU packet to check current states of RSTP.
• Forward Delay Time (4-30): Enter the time in seconds between 4 and 30 that a port
spends changing from its learning and listening state to the forwarding state.
• When finished, click ‘Apply’ button for the configuration to take effect.
Note:
Follow the rule below to configure Max Age, Hello Time, and Forward Delay Time parameters.
2 x (Forward Delay Time value –1) > = Max Age value >= 2 x (Hello Time value +1)
Root Bridge Information
The column fields give the current bridge information for the switch.
• Bridge ID: This field displays the bridge ID by showing the MAC address of this switch.
• Root Priority: This field displays the numerical value indicating bridge priority of the
switch. Generally, the switch with the lowest numerical value in the network is set as the
root bridge.
• Root Port: This field indicates which port is connecting to the root bridge. When the switch
is set as the root bridge, the word ‘Root’ shows here.
• Root Path Cost: This field displays the path cost between the switch’s root port and the
designated port of the root bridge. Path cost is a value to each port typically based on
rules described as part of 802.1d. For the root bridge this is zero. For all other bridges, it
is the sum of the port path costs on the least cost path to the root bridge.