Using Spanning Tree Configuration Commands - Alcatel-Lucent OmniSwitch AOS Release 7 Manual

Configuring Spanning Tree Parameters
Primary port functionality. The path cost assigned to the aggregate link is not the same between
OmniSwitch and Cisco switches since vendor-specific formulas are used to derive the path cost.
Manual configuration is recommended to match the Cisco path cost assignment for an aggregate link.
For more information on the configuration of path cost for aggregate links, refer
Aggregate Ports" on page
The table below shows the default Spanning Tree values.
Parameters
Mac Reduction Mode
Bridge Priority
Port Priority
Port Path Cost
Aggregate Path Cost
Default Path Cost Mode
Max Age
Hello Time
Forward Delay Time
Default Protocol

Using Spanning Tree Configuration Commands

The Alcatel-Lucent Spanning Tree implementation uses commands that contain one of the following
keywords to specify the type of Spanning Tree instance to modify:
•
cist – command applies to the Common and Internal Spanning Tree instance. The CIST is the single
Spanning Tree flat mode instance that is available on all switches. When using STP or RSTP, the CIST
is also known as instance 1 or bridge 1.
•
msti – command applies to the specified Multiple Spanning Tree Instance. When using MSTP
(802.1s), the CIST instance is also known as MSTI 0.
•
vlan – command applies to the specified VLAN instance.
These commands (referred to as explicit commands) allow the configuration of a particular Spanning Tree
instance independent of which mode and/or protocol is currently active on the switch. The configuration,
however, does not go active until the switch is changed to the appropriate mode. For example, if the
switch is running in the per-VLAN mode, the following explicit command changes the MSTI 3 priority to
12288:
-> spantree msti 3 priority 12288
Even though the above command is accepted in the per-VLAN mode, the new priority value does not take
effect until the switch mode is changed to flat mode.
Note. When a snapshot is taken of the switch configuration, the explicit form of all Spanning Tree
commands is captured. For example, if the priority of MSTI 2 was changed from the default value to a
OmniSwitch AOS Release 7 Network Configuration Guide
5-38.
OmniSwitch
Enabled
32768
128
IEEE Port Speed Table
Proprietary Table
Short (16-bit)
20
2
15
RSTP (1w) Per Vlan
March 2011
Using Spanning Tree Configuration Commands
"Path Cost for Link
Cisco
Disabled
32768
32 (catOS) / 128 (IOS)
IEEE Port Speed Table
Avg Path Cost / NumPorts
Short (16-bit)
20
2
15
PVST+ (1d) Per Switch
page 5-25