STP is a Layer 2 protocol that prevents logical loops in switched networks that have redundant links.
The following sections examine why such a protocol is needed in Layer 2 networks. STP terminology and operation are then introduced.
Redundancy in a network, such as that shown in Figure 1-18, is desirable so that communication can still take place if a link or device fails. For example, if switch X in this figure stopped functioning, devices A and B could still communicate through switch Y. However, in a switched network, redundancy can cause problems.
Figure 1-18 Redundancy in a Switched Network Can Cause Problems a
Was this article helpful?