Forward-delay – Brocade Network OS Command Reference v4.1.0 User Manual
Page 349
Network OS Command Reference
311
53-1003115-01
forward-delay
2
forward-delay
Specifies the time an interface spends in each of the listening and learning states.
Synopsis
forward-delay seconds
no forward-delay
Operands
seconds
Specifies the time that an interface spends in the Spanning Tree Protocol
(STP) learning and listening states. Valid values range from 4 through 30
seconds.
Defaults
15 seconds
Command Modes
Protocol Spanning Tree configuration mode
Description
Use this command to specify how long the listening and learning states last before the interface
begins the forwarding of all spanning-tree instances.
STP interface states:
•
Listening - The interface processes the Bridge Protocol Data Units (BPDUs) and awaits
possible new information that might cause it to return to the blocking state.
•
Learning - The interface does not yet forward frames (packets), instead it learns source
addresses from frames received and adds them to the filtering database (switching
database).
•
Forwarding - An interface receiving and sending data, normal operation. STP still monitors
incoming BPDUs that can indicate it should return to the blocking state to prevent a loop.
•
Blocking - An interface that can cause a switching loop, no user data is sent or received,
but it might go to the forwarding state if the other links in use fail and the STP determines
that the interface may transition to the forwarding state. BPDU data continues to be
received in the blocking state.
Usage Guidelines
When you change the spanning-tree forward-delay time, it affects all spanning-tree instances.
When configuring the forward-delay, the following relationship should be kept:
2*(forward-delay - 1)>=max-age>=2*(hello-time + 1)
If xSTP is enabled over VCS, this command must be executed on all the RBridge nodes.
Enter no forward-delay to return to the default settings.
Examples
To configure the forward-delay time to 18 seconds:
switch(conf-mstp)# forward-delay 18
See Also