Alcatel-Lucent OmniSwitch 9900 Series Network Configuration Manual page 160

Configuring Spanning Tree Parameters
Link Speed
10 Mbps
100 Mbps
1G
2.5G
5G
10G
25G
40G
50G
100G
Is a 16-bit path cost value is in use and the path_cost is set to zero, the following IEEE 802.1D
recommended default path cost values based on link speed are used:
Link Speed
10 Mbps
100 Mbps
1G
2.5G
5G
10G
25G
40G
50G
100G
Spanning Tree is automatically enabled on a port and the path cost is set to the default value. If the switch
is running in the per-VLAN Spanning Tree mode, then the port path cost applies to the specified VLAN
instance associated with the port. If the switch is running in the flat Spanning Tree mode, then the port
path cost applies across all VLANs associated with the port. The flat mode instance is specified as the port
instance, even if the port is associated with other VLANs.
The spantree vlan path-cost
switch is running in either mode (per-VLAN or flat). For example, the following command configures a
16-bit path cost value for port 8/1 for VLAN 10 to 19 (the port speed is 100 MB, 19 is the recommended
value):
-> spantree vlan 10 port 8/1 path-cost 19
OmniSwitch AOS Release 8 Network Configuration Guide
32-bit Path Cost
Physical Port
2000000
200000
20000
8000
4000
2000
800
500
400
200
16-bit Path Cost
Physical Port
100
19
4
4
3
2
1
1
1
1
command configures the port path cost value for a VLAN instance when the
32-bit Path Cost
Link Aggregate (2/4/8/16 Port)
1200000, 800000, 600000, 400000
120000, 80000, 60000, 40000
18000, 16000, 14000, 12000
7600, 7200, 6800, 6400
3800, 3600, 3400, 3200
1900, 1800, 1700, 1600
780, 760, 740, 720
480, 460, 440, 420
380, 360, 340, 320
180, 160, 140, 120
16-bit Path Cost Link Aggregate (2/4/8/16 Port)
60, 40, 30, 20
12, 9, 7, 5
3
3
2
1
1
1
1
1
December 2017
Configuring STP Port Parameters
page 6-37