Nortel Networks 2300 manual Configuring and Managing Spanning Tree Protocol

311

Configuring and Managing

Spanning Tree Protocol

Enabling the Spanning Tree Protocol	312
Changing Standard Spanning Tree Parameters	313
Configuring and Managing STP Fast Convergence Features	319
Displaying Spanning Tree Information	326
Spanning Tree Configuration Scenario	332

The purpose of the Spanning Tree Protocol (STP) is to maintain a loop-free network. A loop-free path is accomplished when a device recognizes a loop in the topology and blocks one or more redundant paths.

Mobility System Software (WSS Software) supports 802.1D and Per-VLAN Spanning Tree protocol (PVST+).

•WSS Software uses 802.1D bridge protocol data units (BPDUs) on VLAN ports that are untagged. However, each VLAN still runs its own instance of STP, even if two or more VLANs contain untagged ports. To run a single instance of STP in 802.1D mode on the entire switch, configure all network ports as untagged members of the same VLAN.

•WSS Software uses PVST+ BPDUs on VLAN ports that are tagged. PVST+ BPDUs include tag information in the 802.1Q field of the BPDUs. WSS Software runs a separate instance of PVST+ on each tagged VLAN.

Note. STP does not run on AP access ports or wired authentication ports and does not affect traffic flow on these port types.

Note. When you create a VLAN, STP is disabled on the new VLAN by default, regardless of the STP state of other VLANs on the device.

Note. The IEEE 802.1D spanning tree specifications refer to networking devices that forward Layer 2 traffic as bridges. In this context, an WSS switch is a bridge. Where this manual or the product interface uses the term bridge, you can assume the term is applicable to the WSS switch.

Nortel WLAN Security Switch 2300 Series Configuration Guide