Lantech LGS-2624C, User Manual, Page: 76 / 279

2-4 Spanning Tree
The Spanning Tree Protocol (STP) can be used to detect and disable
network loops, and to provide backup links between switches, bridges or
routers. This allows the switch to interact with other bridging devices (that is,
an STP-compliant switch, bridge or router) in your network to ensure that
only one route exists between any two stations on the network, and provide
backup links which automatically take over when a primary link goes down.
STP - STP uses a distributed algorithm to select a bridging device (STP-
compliant switch, bridge or router) that serves as the root of the spanning
tree network. It selects a root port on each bridging device (except for the
root device) which incurs the lowest path cost when forwarding a packet
from that device to the root device. Then it selects a designated bridging
device from each LAN which incurs the lowest path cost when forwarding a
packet from that LAN to the root device. All ports connected to designated
bridging devices are assigned as designated ports. After determining the
lowest cost spanning tree, it enables all root ports and designated ports,
and disables all other ports. Network packets are therefore only forwarded
between root ports and designated ports, eliminating any possible network
loops.
Once a stable network topology has been established, all bridges listen for
Hello BPDUs (Bridge Protocol Data Units) transmitted from the Root Bridge.
If a bridge does not get a Hello BPDU after a predefined interval (Maximum
Age), the bridge assumes that the link to the Root Bridge is down. This
bridge will then initiate negotiations with other bridges to reconfigure the
network to reestablish a valid network topology.
2-4.1 Bridge Settings
The section describes that how to configure the Spanning Tree Bridge and
STP System settings. It allows you to configure STP System settings are
used by all STP Bridge instance in the Swtich Stack.