Configuring Vlan Bridge Forward Delay Time - Alcatel OmniSwitch 6624 Network Configuration Manual

Configuring Spanning Tree Parameters
To change the VLAN bridge max age time, enter bridge followed by an existing VLAN ID (or VLAN 1 if
using a flat Spanning Tree instance) then max age followed by a numerical value between 6 and 40 to
specify the number of seconds. For example, the following command changes the max age time value for
VLAN 455 to 40 seconds:
-> bridge 455 max age 40
To view the VLAN max age time value, use the
this command, see the OmniSwitch CLI Reference Guide.

Configuring VLAN Bridge Forward Delay Time

The VLAN bridge forward delay time specifies how long, in seconds, a port remains in the listening and
learning states while it is transitioning to a forwarding state. In addition, when a topology change occurs,
the forward delay time value is used to age out all dynamically learned addresses in the MAC address
forwarding table. For more information about the MAC address table, see
Learning."
The forward delay time propagated in a root bridge Configuration BPDU is the value used by all other
bridges in the tree for their own forward delay time. Therefore, if this value is changed for the root bridge
(VLAN), all other VLANs associated with the same STP instance will adopt this value as well.
If the switch is running in the 1x1 Spanning Tree mode, then a forward delay time value is defined for
each VLAN. When a VLAN is created, STP is enabled and the forward delay time defaults to 15 seconds.
If the switch is running in the flat Spanning Tree mode, then the forward delay time value is defined for
VLAN 1. Specifying a low forward delay time may cause temporary network loops, because packets may
get forwarded before STP configuration or change notices have reached all nodes in the network.
To change the VLAN bridge forward delay time, enter bridge followed by an existing VLAN ID (or
VLAN 1 if using a flat Spanning Tree instance) then forward delay followed by a numerical value
between 4 and 30 to specify the number of seconds. For example, the following command changes the
forward delay time value for VLAN 455 to 10 seconds:
-> bridge 455 forward delay 10
To view the VLAN forward delay time value, use the
about this command, see the OmniSwitch CLI Reference Guide.
OmniSwitch 6624/6648 Network Configuration Guide
show spantree command. For more information about
show spantree command. For more information
April 2004
Configuring STP VLAN Parameters
Chapter 2, "Managing Source
page 5-13