Creating A Stable Stp Topology; Stp Port States - D-Link DES-3326 User Manual

DES-3326 Layer 3 Fast Ethernet Switch User's Guide
A designated switch is selected. This is the switch closest
to the root switch through which packets will be forwarded
to the root.
A port for each switch is selected.
providing the best path from the switch to the root switch.
Ports included in the STP are selected.

Creating a Stable STP Topology

If all switches have STP enabled with default settings, the switch
with the lowest MAC address in the network will become the root
switch. By increasing the priority (lowering the priority number)
of the best switch, STP can be forced to select the best switch as the
root switch.
When STP is enabled using the default parameters, the path
between source and destination stations in a switched network
might not be ideal. For instance, connecting higher-speed links to
a port that has a higher number than the current root port can
cause a root-port change. The goal is to make the fastest link the
root port.

STP Port States

The BPDUs take some time to pass through a network.
propagation delay can result in topology changes where a port that
transitioned directly from a Blocking state to a Forwarding state
could create temporary data loops.
network topology information to propagate throughout the network
before starting to forward packets. They must also wait for the
packet lifetime to expire for BPDU packets that were forwarded
based on the old topology. The forward delay timer is used to allow
the network topology to stabilize after a topology change.
addition, STP specifies a series of states a port must transition
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This is the port
Ports must wait for new
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