LevelOne FGL-2870 - Manual (Page 244)

Configuring the Switch
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Once you specify the VLANs to include in a Multiple Spanning Tree Instance (MSTI),
the protocol will automatically build an MSTI tree to maintain connectivity among
each of the VLANs. MSTP maintains contact with the global network because each
instance is treated as an RSTP node in the Common Spanning Tree (CST).
Configuring Port and Trunk Loopback Detection
When Port Loopback Detection is enabled and a port receives it’s own BPDU, the
detection agent drops the loopback BPDU, sends an SNMP trap, and places the
port in discarding mode. This loopback state can be released manually or
automatically. If the port is configured for automatic loopback release, then the port
will only be returned to the forwarding state if one of the following conditions is
satisfied:
• The port receives any other BPDU except for it’s own, or;
• The port’s link status changes to link down and then link up again, or;
• The port ceases to receive it’s own BPDUs in a forward delay interval.
Notes: 1. If Port Loopback Detection is not enabled and a port receives it’s own BPDU,
then the port will drop the loopback BPDU according to IEEE Standard
802.1w-2001 9.3.4 (Note 1).
2. Port Loopback Detection will not be active if Spanning Tree is disabled on
the switch.
3. When configured for manual release mode, then a link down / up event will
not release the port from the discarding state.
Field Attributes
• Port – Indicates the interface to be configured. (Range: 1-28/52)
• Status – Enables Loopback Detection on this interface. (Default: Enabled)
• Trap – Enables SNMP trap notification for loopback events on this port.
(Default: Disabled)
• Release Mode – Configures the port for automatic or manual loopback release.
(Default: Auto)
• Release – Allows a port to be manually released from discard mode. This is only
available if the port is configured for manual release mode.
• Trunk – Indicates if this port is a trunk member.