DES-7000/DES-7100 Layer 2 Switch User
’
s Guide
Switch Management
38
Transition States
Each port on a switch using STP exists is in one of the following five states:
Figure 5.4 below illustrates the STP port transition states.
Figure 5-4. STP Transition States
Port State Transition
When you enable STP, every port on every switch in the network goes through the blocking state and
then transitions through the states of listening and learning at power up. If properly configured, each
port stabilizes to the forwarding or blocking state.
No packets (except BPDUs) are forwarded from, or received by, STP enabled ports until the
forwarding state is enabled for that port.
*Learning may be enabled or disabled for individual ports, please read Port Configuration on page 55
for a description of how the DES-7000/DES-7100 implements learning on the Switch. If it is disabled
for the port, this port state is skipped.
A port transitions from one state to another as
follows:
-
From initialization (switch boot) to blocking
-
From blocking to listening or to disabled
-
From listening to learning or to disabled
-
From learning to forwarding or to disabled
-
From forwarding to disabled
-
From disabled to blocking
Blocking
The port is blocked from forwarding or receiving
packets.
Listening
The port is waiting to receive BPDU packets that
may tell the port to go back to the blocking state.
Learning*
The port is adding addresses to its forwarding
database, but not yet forwarding packets.
Forwarding
The port is forwarding packets.
Disabled
The port only responds to network management
messages and must return to the blocking state
first.
Summary of Contents for DES-7000 Series
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