What Is Stp - IBM 8271 Nways F12 User Manual

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What is STP?

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STP is a bridge-based system for providing fault tolerance on networks.
It allows you to implement parallel paths for network traffic, and
ensure that:
Redundant paths are disabled when the main paths are operational
Redundant paths are enabled if the main paths fail
As an example, Figure 6-1 shows a network containing three LAN
segments separated by three bridges. With this configuration, each
segment can communicate with the others using two paths. This
configuration creates loops which cause the network to overload;
however, STP allows you to have this configuration because it detects
duplicate paths and immediately prevents, or blocks, one of them from
forwarding traffic.
Figure 6-2 shows the result of enabling STP on the bridges in the
configuration. The STP system has decided that traffic from LAN
segment 2 to LAN segment 1 can only flow through Bridges C and A.
If the link through Bridge C fails, as shown in Figure 6-3, the STP
system reconfigures the network so that traffic from segment 2 flows
through Bridge B.
A network configuration that creates loops
Figure 6-1