One of the most important modern developments in computing is not related to the size of machines or the speed or type of the processor, but is all about connecting machines together, so that data and other resources can be shared, even over great distances.
Linux is not in any sense being left behind in its ability to connect to other Systems - both other Linux and non-Linux Systems. Indeed, it makes available all of the popular standard communication mechanisms.
As a system administrator, there are many things you may need to know in order that you can properly establish the communication links between your machine and others you require. In particular, you may be involved in the installation and setup of serial or parallel line links or ethernet connections, and in the configuration of the machine to operate on these links.