Hirschmann MACH 4000 Reference Manual

Redundancy
204
7.5 Spanning Tree
RM Web
Release 6.0 07/2010
Loop Guard The “Loop Guard” setting is only meaningful
for ports with the STP role alternate,
backup or root. If the “Loop Guard” setting is
active and the port has not received any STP-
BPDUs for a while, the device sets the port to
the discarding condition (port sends no
more data).
The device also sets the port to what is known
as the “loop status”. This is displayed in the
“Loop Status” column.
The device thus prevents a potential loop if no
more STP-BPDUs are received if, for example,
STP is switched off on the remote device, or
the link only fails in the receiving direction.
When the port receives BPDUs again, the
device resets the loop status of the port to
false, and the transmission status of the port
according to the port role.
If the “Loop Guard” setting is inactive,
however, the device sets the port to the
forwarding status when STP-BPDUs have
not been received.
Note: The “Root Guard” and “Loop Guard”
settings are mutually exclusive. If you activate
one setting when the other is already active,
the device switches off the other one.
active (box
selected),
inactive (box
empty)
inactiv
e
Loop Status
(read only)
Display the status of the Loop Status.
The device sets the loop status of the port to
true if the “Loop Guard” setting is active at
the port and the port is not receiving any more
STP-BPDUs.
Here the device leaves the port in the
discarding transmission status, to prevent a
potential loop.
When the port receives STP-BPDUs again,
the device resets the loop status to false.
true, false -
Transitions to
Loop Status
(read only)
Counts how often the device has set the port
to the loop status (“Loop Status” column
true).
0 - 4,294,967,295
(2
32
-1)
0
Parameter Meaning Possible Values Default
Setting
Table 91: Port-related STP settings and displays, guards

Hirschmann MACH 4000 Specifications

General

Brand	Hirschmann
Model	MACH 4000
Category	Network Router
Language	English