show voice port - Tecnológico de Costa Rica

Establishing Timeouts
Node Address Aging
Using the Spanning-Tree Protocol 8 - 7
If the port is still part of the spanning tree at the end of the listening
period it is put in the learning state. In this state it can still receive and
transmit configuration messages, but is also allowed to learn the source
addresses from the packets received from its LAN. It is still not allowed
to forward any packets. The learning state is used to lessen the amount
of flooding of unknown destination addresses that would occur if the
port started forwarding before there were any entries in its learning
table.
Once the learning period is over, the port is allowed to forward data
normally.
The configured timeout values on the root bridge are passed to each
bridge in a configuration message to ensure that all bridges on the infrastructure
are using the same timeout periods.
The root bridge puts its own values in its messages. All other bridges
copy the values contained in the configuration message sent to them
from their root port. The value in this message is used in all of the
bridge’s transmitted messages. Using this method, the values are propagated
throughout the infrastructure.
Occasionally stations may be moved from one LAN to another. The
bridges will remove learned addresses from their tables if no packets
have been received from a node for a period of time.
If node addresses do not timeout, the bridge may continue to send packets
for a node to the wrong LAN. If a node sends packets from its new
LAN location, the tables might be corrected, however, this is not guaranteed.
The default timeout period is 5 minutes.
If a new bridge or port is added to an infrastructure, the ports included
in the spanning tree could change dramatically. It may appear that a
node has changed location very quickly.
To allow for these quick changes of location, the spanning tree protocol
specifies that every time a port enters the blocked or forwarding states,
its bridge must send a topology changed message to the root bridge.