FTOS Configuration Guide for the C-Series - Force10 Networks

Modifying Global Parameters
You can modify Spanning Tree parameters. The root bridge sets the values for forward-delay, hello-time,
and max-age and overwrites the values set on other bridges participating in Spanning Tree.
Note: Force10 Networks recommends that only experienced network administrators change the Spanning
Tree parameters. Poorly planned modification of the Spanning Tree parameters can negatively impact
network performance.
Table 39 displays the default values for Spanning Tree.
Table 39 STP Default Values
STP Parameter Default Value
Forward Delay 15 seconds
Hello Time 2 seconds
Max Age 20 seconds
Port Cost 100-Mb/s Ethernet interfaces 19
1-Gigabit Ethernet interfaces 4
10-Gigabit Ethernet interfaces 2
Port Channel with 100 Mb/s Ethernet interfaces 18
Port Channel with 1-Gigabit Ethernet interfaces 3
Port Channel with 10-Gigabit Ethernet interfaces 1
Port Priority 8
To change STP global parameters:
Task Command Syntax Command Mode
Change the forward-delay parameter (the wait time before the
interface enters the forwarding state).
• Range: 4 to 30
• Default: 15 seconds
Change the hello-time parameter (the BPDU transmission
interval).
Note: With large configurations (especially those with more
ports) Force10 Networks recommends that you increase the
hello-time.
Range: 1 to 10
Default: 2 seconds
forward-delay seconds PROTOCOL
SPANNING TREE
hello-time seconds PROTOCOL
SPANNING TREE
FTOS Configuration Guide, version 7.7.1.0 391