Alcatel-Lucent 6850-48 网络指南
Configuring Spanning Tree Parameters
Configuring STP Bridge Parameters
OmniSwitch AOS Release 6 Network Configuration Guide
September 2009
page 13-23
The explicit
command configures the max age time for a VLAN instance when the
switch is running in either mode (1x1 or flat). For example, the following command performs the same
function as the command in the previous example:
function as the command in the previous example:
-> bridge 1x1 455 max age 10
To change the max age time value for the flat mode instance, use either the
command or
the
command. Note that both commands are available when the switch is running in
either mode (1x1 or flat) and an instance number is not required. For example, the following commands
change the max age time for the flat mode instance to 10:
change the max age time for the flat mode instance to 10:
-> bridge max age 10
-> bridge cist max age 10
As in previous releases, it is possible to configure the flat mode instance with the bridge max age
command by specifying 1 as the instance number (e.g., bridge 1 max age 30). However, this is only avail-
able when the switch is already running in the flat mode and STP or RSTP is the active protocol.
command by specifying 1 as the instance number (e.g., bridge 1 max age 30). However, this is only avail-
able when the switch is already running in the flat mode and STP or RSTP is the active protocol.
Note that the max age time is not configurable for Multiple Spanning Tree Instances (MSTI). These
instances inherit the max age time from the flat mode instance (CIST).
instances inherit the max age time from the flat mode instance (CIST).
Configuring the Bridge Forward Delay Time
The bridge forward delay time specifies how long, in seconds, a port remains in the learning state 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
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
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,
all other bridges associated with the same instance will adopt this value as well.
bridges in the tree for their own forward delay time. Therefore, if this value is changed for the root bridge,
all other bridges associated with the same 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 instance. If the switch is running in the flat Spanning Tree mode, then the forward delay time
value is defined for the flat mode instance. In both cases, the default forward delay time used is 15
seconds.
each VLAN instance. If the switch is running in the flat Spanning Tree mode, then the forward delay time
value is defined for the flat mode instance. In both cases, the default forward delay time used is 15
seconds.
Note that specifying a low forward delay time may cause temporary network loops, because packets may
get forwarded before Spanning Tree configuration or change notices have reached all nodes in the
network.
get forwarded before Spanning Tree configuration or change notices have reached all nodes in the
network.
To change the bridge forward delay time value for a VLAN instance, specify a VLAN ID with the
command when the switch is running in the 1x1 mode. For example, the following
command changes the forward delay time for VLAN 455 to 10 seconds:
-> bridge 455 forward delay 20
The explicit
command configures the forward delay time for a VLAN instance
when the switch is running in either mode (1x1 or flat). For example, the following command performs
the same function as the command in the previous example:
the same function as the command in the previous example:
-> bridge 1x1 455 forward delay 20
To change the forward delay time value for the flat mode instance, use either the
command or the
switch is running in either mode (1x1 or flat) and an instance number is not required. For example, the
following commands change the forward delay time for the flat mode instance to 10:
following commands change the forward delay time for the flat mode instance to 10: