Before Layer 2 Switching

Let’s go back in time a bit and take a look at the condition of networks before switches and how switches have helped segment the corporate LAN. Before LAN switching, the typical network design looked like the network in Figure 10-1.

Figure 10-1: Before switching

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The design in Figure 10-1 was called a collapsed backbone because all hosts would need to go to the corporate backbone to reach any network services—both LAN and mainframe.

Going back even further, before networks like the one shown in Figure 10-1 had physical segmentation devices such as routers and hubs, there was the mainframe network. This network included ...

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