Network Router User Manual

Web OS 10.0 Application Guide
Chapter 2: VLANs
49
212777-A, February 2002
VLANs and Spanning Tree Protocol
Spanning Tree Protocol (STP) detects and eliminates logical loops in a bridged or switched
network. STP forces redundant data paths into a standby (blocked) state. When multiple paths
exist, Spanning Tree configures the network so that a switch uses only the most efficient path.
If that path fails, Spanning Tree automatically sets up another active path on the network to
sustain network operations.
The relationship between port, trunk groups, VLANs, and Spanning Trees is shown in
Table 2-1.
NOTE – Due to Spanning Tree’s sequence of listening, learning, and forwarding or blocking,
lengthy delays may occur. For more information on using STP in cross-redundant topologies,
see “Eliminating Loops with STP and VLANs” on page 278.
Table 2-1 Ports, Trunk Groups, and VLANs
Switch Element Belongs to
Port Trunk group
or
One or more VLANs
Trunk group One or more VLANs
VLAN One Spanning Tree group