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You can modify each port state by using management software. 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.
2. STP Parameters
STP Operation Levels
The Switch allows for two levels of operation: the switch level and the port level. The switch level forms a spanning tree
consisting of links between one or more switches. The port level constructs a spanning tree consisting of groups of one or more
ports. The STP operates in much the same way for both levels.
On the switch level, STP calculates the Bridge Identifier for each switch and then sets the Root
Bridge and the Designated Bridges. On the port level, STP sets the Root Port and the Designated
Ports.
The following are the user-configurable STP parameters for the switch level:
Parameter
Bridge Identifier(Not user
configurable
except by setting priority
below)
Figure 4-6-1: STP Port State Transitions
Description
A combination of the User-set priority and
the switch's MAC address.
The Bridge Identifier consists of two parts:
a 16-bit priority and a 48-bit Ethernet MAC
address 32768 + MAC
163
User's Manual of IGS-4215 PoE Series
Default Value
32768 + MAC
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