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WAGO-ETHERNET-Zubehör 852
Enhanced Features
91
852-1305 8/4-Port 100BASE-T/1000BASE-SX/LX
Manual
1.1.0
Table 25: STP Path Costs
Transmission Speed Recommended Value Recommended Range Permissible Range
4 Mbps
250
100 … 1000
1 … 65535
10 Mbps
100
50 … 600
1 … 65535
16 Mbps
62
40 … 400
1 … 65535
100 Mbps
19
10 … 60
1 … 65535
1 Gbps
4
3 … 10
1 … 65535
10 Gbps
2
1 … 5
1 … 65535
•
Each “Bridge” communicates with the “Root Bridge” via the “Root Port”.
The “Root Port” is the port on the switch with the lowest path costs to the
“Root Bridge” (the “Root Path Cost”). If there is no “Root Port”, then the
switch becomes the “Root Bridge” for the “Spanning Tree” network
•
A “Designated Bridge” is selected for each LAN segment. This bridge has
the lowest cost to the “Root Bridge” among the bridges connected to the
LAN.
Forward Time (Forward Delay)
The “Forward Time” is the maximum time (in seconds) that the switch wats
before it changes states. This delay is required because every switch must first
receive information on topology changes before it forwards frames. In addition,
each port needs time to receive information on conflicts that would make it return
to the blocking state. Otherwise, temporary data loops might result. The valid
range is 4 to 30 seconds.
Max Age
The “Max Age” is the maximum time (in seconds) that the switch can wait
without receiving a BPDU (“
B
ridge
P
rotocol
D
ata
U
nit”, configuration message)
before attempting to reconfigure. All switch ports (except for “Designated Ports”)
receive BPDUs at regular intervals. Each port that ages out STP information
(from the last BPDU) becomes the “Designated Port” for the attached LAN. If it
is a “Root Port”, a new “Root Port” is selected from among the switch ports
attached to the network.
Hello Time
The “Hello Time” is the time interval in seconds between configuration messages
(BDPU “Bridge Protocol Data Unit”) sent from the root switch.