3.4 Summary-Chapter 3

So now we have looked at the “lowest” layer in our four-layer architecture. And we have only taken a simple look at how the Link layer works. There are many other details that must be designed into a link layer like connection distance, voltage, frequency, speed, and many others.
A key benefit of the layered architecture is that engineers who design and build Link layer technologies can ignore all of the issues that are handled by the layers above the Link layer. This allows them to focus on building the best possible solution to moving data across a single “hop”. Modern-day link layers like WiFi, satellite, cable modems, Ethernet, and cellular technology are very well developed. Data moves so quickly and seamlessly that once we get our connection we rarely have to worry about the Link layer. It just works.

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