sion is necessary here. STP is used by layer 2 bridges to stop network loops
in networks that have more than one physical link to the same network.
There is a limit to the number of links in a layer 2 switched backbone that
needs to be taken into account. As you increase the number of core switches,
the problem becomes that the number of links to distribution links must
increase also, for redundancy reasons. If the core is running the Spanning
Tree Protocol, then it can compromise the high-performance connectivity
between switch blocks. The best design on the core is to have two switches
without STP running. You can do this only by having a core without links
between the core switches. This is demonstrated in Figure 1.11.