Users Guide

To change these parameters, use the following commands.
• Change the forward-delay parameter.
PROTOCOL SPANNING TREE RSTP mode
forward-delay seconds
The range is from 4 to 30.
The default is 15 seconds.
• Change the hello-time parameter.
PROTOCOL SPANNING TREE RSTP mode
hello-time seconds
NOTE: With large configurations (especially those configurations with more ports) Dell Networking
recommends increasing the hello-time.
The range is from 1 to 10.
The default is 2 seconds.
• Change the max-age parameter.
PROTOCOL SPANNING TREE RSTP mode
max-age seconds
The range is from 6 to 40.
The default is 20 seconds.
To view the current values for global parameters, use the show spanning-tree rstp command from
EXEC privilege mode.
Enabling SNMP Traps for Root Elections and
Topology Changes
To enable SNMP traps, use the following command.
• Enable SNMP traps for RSTP, MSTP, and PVST+ collectively.
snmp-server enable traps xstp
Modifying Interface Parameters
On interfaces in Layer 2 mode, you can set the port cost and port priority values.
• Port cost — a value that is based on the interface type. The previous table lists the default values. The
greater the port cost, the less likely the port is selected to be a forwarding port.
• Port priority — influences the likelihood that a port is selected to be a forwarding port in case that
several ports have the same port cost.
Rapid Spanning Tree Protocol (RSTP) 810