Filter
Top Products
4-4 C
HAPTER
4: M
ONITORING
DUA1860-0AAA01
Port State:
Display Field. Displays the ports and their present
state. The possible states are
MOS
,
Forwarding
,
Blocking
,
Listening
and
Learning
.
The external port may go into a disconnected state (
DCONN
) when
a segment has not been attached, or a transceiver module is not
fitted.
MOS
(Manually Out of Service) means that the port has been
manually disabled by a bridge administrator. No network traffic
passes through it.
Forwarding
means that the port is bridging packets and
spanning tree calculations. All root ports and designated ports are
in forwarding state, and these are the only ports that are ever in
the forwarding state. If one bridge receives information from
another bridge indicating that one of its ports should not be a
root bridge or a designated port, that port is placed in the
blocked state.
Blocking
means that the port does not forward packets but is
included in the spanning tree calculations. Ports enter the
blocking state by a network administrator who enables a disabled
port, or when spanning tree determines that the port creates an
active loop in the network.
Listening
means that the port is preparing to enter the active
topology. At this point the port is not used for bridging packets,
but C-BPDUs are received and transmitted on it, and it is included
in the spanning tree calculations. If, after a predetermined
amount of time, no information has been received indicating that
the port should be blocked, the port passes into the learning
state.