LevelOne FGL-2870 - Manual (Page 259)

Spanning Tree Algorithm Configuration
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link type is point-to-point; otherwise it equals the spanning-tree’s maximum age
(see "Configuring Global Settings for STA" on page 3-194).
An interface cannot function as an edge port under the following conditions:
- If spanning tree mode is set to STP (page 3-194), edge-port mode can be
manually enabled or set to auto, but will have no effect.
- If loopback detection is enabled (page 3-191) and a loopback BPDU is detected,
the interface cannot function as an edge port until the loopback state is released.
- If an interface is in forwarding state and its role changes, the interface cannot
continue to function as an edge port even if the edge delay time has expired.
If the port does not receive any BPDUs after the edge delay timer expires, its role
changes to designated port and it immediately enters forwarding state (see
"Displaying Interface Settings for STA" on page 3-198).
The edge delay time equals the protocol migration time when the port link type
is point-to-point (which is 3 seconds as defined in IEEE 802.3D-2004 17.20.4),
otherwise it equals the maximum age for configuration messages (see
"Displaying Global Settings for STA" on page 3-191).
• BPDU Guard – This feature protects edge ports from receiving BPDUs. It prevents
loops by shutting down an edge port when a BPDU is received instead of putting it
into the spanning tree discarding state. In a valid configuration, configured edge
ports should not receive BPDUs. If an edge port receives a BPDU an invalid
configuration exists, such as a connection to an unauthorized device. The BPDU
guard feature provides a secure response to invalid configurations because an
administrator must manually enable the port. (Default: Disabled)
• BPDU Filter – BPDU filtering allows you to avoid transmitting BPDUs on
configured edge ports that are connected to end nodes. By default, STA sends
BPDUs to all ports regardless of whether administrative edge is enabled on a port.
BDPU filtering is configured on a per-port basis. (Default: Disabled)
Web – Click Spanning Tree, STA, Port/Trunk Edge Port Configuration. Modify the
required attributes, then click Apply.
Figure 3-116 Configuring Edge Port Parameters