Digisol DG-GS4826S Management Manual page 226

C 8 | Spanning Tree Algorithm
HAPTER
Configuring Interface Settings for STA
An interface cannot function as an edge port under the following
conditions:
If spanning tree mode is set to STP
n
cannot automatically transition to operational edge-port state using
the automatic setting.
If loopback detection is enabled
n
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
n
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
n
expires, its role changes to designated port and it immediately
enters forwarding state (see
on page 227).
BPDU Guard – This feature protects edge ports from receiving
5
u
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
5
u
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)
Migration – If at any time the switch detects STP BPDUs, including
u
Configuration or Topology Change Notification BPDUs, it will
automatically set the selected interface to forced STP-compatible
mode. However, you can also use the Protocol Migration button to
manually re-check the appropriate BPDU format (RSTP or STP-
compatible) to send on the selected interfaces. (Default: Disabled)
W I
EB NTERFACE
To configure interface settings for STA:
1. Click Spanning Tree, STA.
2. Select Configure Interface from the Step list.
3. Select Configure from the Action list.
4.
Modify any of the required attributes.
5. Admin Edge Port must be enabled to use this feature.
– 226 –
(page 217), edge-port mode
(page 216) and a loopback BPDU is
"Displaying Interface Settings for STA"