Nortel Optivity Switch, Using Manual

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56 Chapter 4 Using VLAN Manager
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You control path redundancy for VLANs by implementing the Spanning Tree
Protocol (STP).
Spanning Tree Protocol
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.
Table 10 lists the maximum number of STGs and VLANs supported by the
different switches.
For more information about VLANs and Spanning Tree Protocol, refer to
Networking Concepts for the Passport 1000 Series Routing Switch Release 2.0
and Networking Concepts for the Passport 8000 Series Routing Switch .
Table 10 Maximum STGs and VLANs supported by 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 350/410/450 switches 1 64
Business Policy Switch 2000 1 64