Spanning Tree Algorithm Configuration
3-145
3
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.
• 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
mode. (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.
Web
– Click Spanning Tree, Port Loopback Detection or Trunk Loopback Detection.
Modify the required attributes, then click Apply.
Figure 3-90 Configuring Port Loopback Detection
Summary of Contents for 6128PL2
Page 2: ......
Page 8: ...viii ...
Page 26: ...Contents xviii ...
Page 30: ...Tables xxii ...
Page 52: ...Initial Configuration 2 10 2 ...
Page 308: ...Configuring the Switch 3 256 3 ...
Page 473: ...SNMP Commands 4 165 4 ...
Page 644: ...Command Line Interface 4 336 4 ...
Page 648: ...Software Specifications A 4 A ...
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