D-Link DES-3250TG User Manual page 65

In addition to setting Spanning Tree parameters for use on the switch level, the switch allows for the
configuration of a group of ports. This STP Group will use the switch-level parameters entered above,
with the addition of Port Priority and Port Cost.
The STP Group spanning tree works in the same way as the switch-level spanning tree, but the root
bridge concept is replaced with a root port concept. A root port is a port of the group that is elected on
the basis of port priority and port cost, to be the connection to the network for the group. Redundant
links will be blocked, just as redundant links are blocked on the switch level.
The STP on the switch level blocks redundant links between switches (and similar network devices). The
port level STP will block redundant links within the STP Group.
The following fields can be set:
D-Link DES-3250TG Standalone Layer 2 Switch
Parameter
From and To
State<Disabled>
Cost
Priority
Migration <No>
Edge <No>
Description
Consecutive groups of ports may be
configured starting with the selected
port.
Toggle to enable STP on the selected
ports.
A Port Cost can be set from 1 to
200000000. The lower the number,
the greater the probability the port
will be chosen to forward packets.
Default port cost:
100Mbps port = 200000
Gigabit ports = 20000
A Port Priority can be from 0 to 240.
The lower the number, the greater
the probability the port will be
chosen as the Root Port.
Select Yes or No. Choosing Yes will
enable the port to migrate from
802.1d STP status to 802.1w RSTP
status. RSTP can
standard STP, however the benefits
of RSTP are not realized on a port
where an 802.1d network connects
to an 802.1w enabled
Migration should be enabled (Yes) on
ports connected to network stations
or segments that will be upgraded to
802.1w RSTP on all or some portion
of the segment.
Select Yes or No. Choosing Yes
designates the port as an edge port.
Edge ports cannot create
however an edge port can lose edge
port status if a topology change
creates a potential for a loop. An
57
coexist with
network.
loops,