As defined in the IEEE 802.1D standard, the Spanning Tree Protocol detects and eliminates logical loops in a bridged or switched network. When multiple paths exist, the spanning tree algorithm configures the network so that a bridge or switch uses only the most efficient path. If that path fails, the protocol automatically reconfigures the network to make another path active, thus sustaining network operations.
The collection of ports in one spanning tree is called a spanning tree group (STG) and a network may include multiple instances of STGs. All the devices supported by Optivity Switch Manager support at least one STG. The Passport 1000 Series switch and the Passport 8600 modules support multiple spanning trees, thus multiple spanning tree groups.
The following table lists the maximum number of STGs and VLANs supported by the different switches.
Switch
Maximum
number of STGs
Maximum
number of VLANs
Passport 1000 Series switch
25
124
Passport 8100 modules
1
2000
Passport 8600 modules
25
1979
BayStack 350/410/420/450 switches
1
64
Business Policy Switch 2000 v 1.0
1
64
Business Policy Switch 2000 v 2.0
6
265
For more information about VLANs and Spanning Tree Protocol, refer to Networking Concepts for the Passport 1000 Series Switch and Networking Concepts for the Passport 8000 Series Switch.
See also: