An Example of IP Routing

The next several pages walk you through an example that discusses each routing step, in order, through multiple devices. That example uses a case in which host A (172.16.1.9) sends a packet to host B (172.16.2.9), with host routing logic and the five steps showing how R1 forwards the packet.

Figure 16-3 shows a typical IP addressing diagram for an IPv4 network with typical address abbreviations. The diagram can get a little too messy if it lists the full IP address for every router interface. When possible, these diagrams usually list the subnet, and then the last octet or two of the individual IP addresses—just enough so that you know the IP address, but with less clutter. For example, host A uses IP address 172.16.1.9, ...

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