Reference Guide

Rapid Spanning Tree Protocol (RSTP) | 467
• Max-age is the length of time the bridge maintains configuration information before it refreshes that
information by recomputing the RST topology.
Table 27-2 lists the default values for RSTP.
To change these parameters, use the following commands, on the root bridge:
To view the current values for global parameters, use the show spanning-tree rstp command from EXEC
privilege mode (Figure 27-5).
Note: Dell Force10 recommends that only experienced network administrators change the RST group
parameters. Poorly planned modification of the RSTG parameters can negatively impact network
performance.
Table 27-2. RSTP Default Values
RSTP Parameter Default Value
Forward Delay 15 seconds
Hello Time 2 seconds
Max Age 20 seconds
Port Cost 40-Gigabit Ethernet interfaces 1400
10-Gigabit Ethernet interfaces 2000
Port Channel with two 40-Gigabit Ethernet interfaces 600
Port Channel with two 10-Gigabit Ethernet interfaces 1800
Port Priority 128
Task Command Syntax Command Mode
Change the forward-delay parameter.
• Range: 4 to 30
• Default: 15 seconds
forward-delay seconds PROTOCOL
SPANNING TREE
RSTP
Change the hello-time parameter.
Note: With large configurations (especially those with more ports) Dell
Force10 recommends that you increase the hello-time.
Range: 1 to 10
Default: 2 seconds
hello-time seconds PROTOCOL
SPANNING TREE
RSTP
Change the max-age parameter.
Range: 6 to 40
Default: 20 seconds
max-age seconds PROTOCOL
SPANNING TREE
RSTP