Alcatel-Lucent 6850-48 Guida Di Rete
Configuring Spanning Tree Parameters
Configuring STP Bridge Parameters
OmniSwitch AOS Release 6 Network Configuration Guide
September 2009
page 13-17
For more information on the configuration of path cost for aggregate links, refer
.
The table below shows the default Spanning Tree values.
Configuring STP Bridge Parameters
The Spanning Tree software is active on all switches by default and uses default bridge and port parame-
ter values to calculate a loop free topology. It is only necessary to configure these parameter values if it is
necessary to change how the topology is calculated and maintained.
ter values to calculate a loop free topology. It is only necessary to configure these parameter values if it is
necessary to change how the topology is calculated and maintained.
Note the following when configuring Spanning Tree bridge parameters:
• When a switch is running in the 1x1 Spanning Tree mode, each VLAN is in essence a virtual bridge
with its own Spanning Tree instance and configurable bridge parameters.
• When the switch is running in the flat mode and STP (802.1D) or RSTP (802.1w) is the active proto-
col, bridge parameter values are only configured for the flat mode instance.
• If MSTP (802.1s) is the active protocol, then the priority value is configurable for each Multiple Span-
ning Tree Instance (MSTI). All other parameters, however, are still only configured for the flat mode
instance and are applied across all MSTIs.
instance and are applied across all MSTIs.
• Bridge parameter values for a VLAN instance are not active unless Spanning Tree is enabled on the
command to enable or
disable a VLAN Spanning Tree instance.
• If Spanning Tree is disabled on a VLAN, active ports associated with that VLAN are excluded from
Spanning Tree calculations and will remain in a forwarding state.
• Note that when a switch is running in the flat mode, disabling Spanning Tree on VLAN 1 disables the
instance for all VLANs and all active ports are then excluded from any Spanning Tree calculations and
will remain in a forwarding state.
will remain in a forwarding state.
To view current Spanning Tree bridge parameter values, use the
command.
For more information about this command, see the OmniSwitch CLI Reference Guide.
Parameters
OmniSwitch
Cisco
Mac Reduction Mode
Enabled
Disabled
Bridge Priority
32768
32768
Port Priority
128
32 (catOS) / 128 (IOS)
Port Path Cost
IEEE Port Speed Table
IEEE Port Speed Table
Aggregate Path Cost
Proprietary Table
Avg Path Cost / NumPorts
Default Path Cost Mode
Short (16-bit)
Short (16-bit)
Max Age
20
20
Hello Time
2
2
Forward Delay Time
15
15
Default Protocol
RSTP (1w) Per Vlan
PVST+ (1d) Per Switch