WAGO 852-1305 Manual page 92

92 Enhanced Features WAGO-ETHERNET-Zubehör 852
852-1305 8/4-Port 100BASE-T/1000BASE-SX/LX
STP
After a bridge determines the lowest cost "Spanning Tree" with STP, it enables
the "Root Port" and "Designated Ports" for connected LANs, and disables all
other ports that participate in STP. Network packets are therefore only forwarded
between enabled ports, eliminating any possible network loops.
STP-aware switches exchange BPDUs periodically. If the topology changes in a
LAN coupled via bridge, a new tree is spanned. Once a stable network topology
has been established, all bridges listen for "Hello BPDUs" transmitted from the
"Root Bridge". If a bridge does not get a "Hello BPDU" after a predefined
interval ("Max Age"), the bridge assumes that the link to the "Root Bridge" is
down. This bridge then initiates negotiations with other bridges to reconfigure the
network to re-establish a valid network topology.
Edge Port
"Edge Ports" are attached to a LAN that has no other bridges attached. These
ports can transition directly to the "Forwarding" state. RSTP still continues to
monitor the port for BPDUs in case a bridge is connected. RSTP can also be
configured to automatically detect "Edge Ports". As soon as the bridge detects a
BPDU coming to an "Edge Port", the port loses its status as an "Edge Port".
Forward Delay
The "Forward Delay" is the maximum time (in seconds) that the root devices
waits before changing states (e.g., from "Listening" to "Learning" to
"Forwarding"). The valid range is from 4 to 30 seconds.
Transmission Limit
The "Transmission Limit" is used to configure the minimum interval between the
transmission of consecutive RSTP BPDUs. This function can only be enabled in
RSTP mode. The valid range is from 1 to 10 seconds.
Bridge Priority
"Bridge Priority" is used in selecting the root switch, root port and "Designated
Port". The switch with the highest priority becomes the STA root switch. If all
switches have the same priority, however, the switch with the lowest MAC
address becomes the root switch.
Manual
1.1.0