Discontiguous networking example

FIGURE 2 . 4 Discontiguous networking example
If automatic route summarization is configured (with classful routing protocols, it is, and it
cannot be disabled), then both RouterA and RouterB in Figure 2.4 will be advertising to the
WAN cloud that they are the route to network 172.16.0.0/16. While there are techniques and
alternate routing protocols to overcome this behavior that will be discussed in the “Route Summarization”
section later in this chapter, it makes for better network design to not separate a
network’s subnets by another network when using classful routing protocols.