Lucent Technologies P550 - Manual (Page 230)

Using VLANs, Spanning Tree, and Hunt Groups (Layer 2 and Layer 3)
12 -8 Cajun P550/P220 Switch Operation Guide
Table 12-3. Spanning Tree Options
4. Click APPLY save your changes, or CANCEL to restore previous settings.
5. In the Bridge column, click on a bridge name to set bridge parameters. The
Spanning Tree Bridge Configuration dialog box opens.
6. Use Table 12-4 to select bridge-level parameters:
Parameter Definition
IEEE 802.1D Entire switch is a single IEEE 802.1D-compliant bridge.
Note: When the spanning tree mode is set to IEEE 802.D,
BPDUs are sent out ports in Clear (non-trunked) format even if
the port has a trunking format (3Com, 802.1Q or Dual Layer)
defined.
Per VLAN Each VLAN functions as a separate IEEE 802.1D-compliant
bridge.
Note: If you disable spanning tree on a single VLAN, spanning
tree will be re-enabled when the switch is reset.
In order for spanning tree to function properly with 3Com
trunked ports, the spanning tree mode should be set to
per-VLAN. In Per VLAN spanning tree, there is one instance of
spanning tree for each VLAN and the BPDUs are tagged with the
VLAN ID, ensuring they are interpreted correctly on the
receiving end.
Dual Layer Spanning tree terminates at edge of the switch network.
Spanning Tree per VLAN within the switch network.
Disable Spanning tree not used.
Table 12-4. Bridge-Level Parameters
Parameter Definition
Mode Determines whether spanning tree is enabled or disabled for
this bridge.
Priority STP Priority level for this bridge.
Bridge Max Age Sets the maximum amount of time that this bridge retains
bridging information before discarding. When the
maximum age expires, the bridge assumes it has lost
connection to the network, and sends out requests to be
re-added to the spanning tree.
Bridge Hello Time Time between generation of BPDUs by the root bridge.