User`s manual
211
DWS-1008 User’s Manual
D-Link Systems, Inc.
Conguring and Managing STP
Configuring and Managing
Spanning Tree Protocol
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 (MSS) supports 802.1D and Per-VLAN Spanning Tree protocol
(PVST+).
• MSS 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, congure all network ports as untagged members of the same VLAN. MSS
does not support running 802.1D on multiple tagged VLANs.
• MSS uses PVST+ BPDUs on VLAN ports that are tagged. PVST+ BPDUs include tag
information in the 802.1Q eld of the BPDUs. MSS runs a separate instance of PVST+
on each tagged VLAN.
Enabling the Spanning Tree Protocol
STP is disabled by default. You can enable STP globally or on individual VLANs. To enable
STP, use the following command:
set spantree {enable | disable}
[{all | vlan vlan-id | port port-list vlan-id}]
To enable STP on all VLANs congured on a DWS-1008 switch, type the following
command:
DWS-1008# set spantree enable
success: change accepted.
To verify the STP state and display the STP parameter settings, enter the show spantree
command.
Changing Standard Spanning Tree Parameters
You can change the following standard STP parameters:
• Bridge priority
• Port cost
• Port priority