Episode 05

Ethernet Switches Segment 1 of 3


Ethernet Switches are a lot like Ethernet Hubs; they look the same, and they wire into your network in the same places.

If you’ve seen the AskMisterWizard.com movie entitled, “Ethernet Hubs Explained,” then you already know a lot about Hubs, and you’re ready for this movie. If you haven’t seen that one yet, you ought to watch it first, because this movie explains the differences between Hubs and Switches based on what you learned in that movie.

Ethernet Hubs and Ethernet Switches are so similar, that they’re often mistaken for one another and are often sold as if each were the other. Nowadays, it’s getting harder and harder to buy Hubs because they are being replaced in the marketplace by Switches. And if you buy a box that’s labeled “Hub” in today’s marketplace, there’s a pretty good chance that it’s actually a Switch.

To further underscore the similarities between Hubs and Switches, when you first install a  Switch, it operates exactly like a Hub until it learns gradually about your local area network and applies its one new trick. Also, if your  Switch ever becomes confused by perverse activity on your network, it will revert back to operating exactly like a  Hub.

Remember from our previous discussions about how a Hub has no brain? It’s just a completely mindless device that merges several Ethernet connectors onto a single Ethernet segment, and any traffic seen on any connector is relayed or broadcast out on all of the connectors.

Well, an Ethernet Switch starts out doing exactly the same thing, but it has a teeny, tiny little brain. And as it relays information from the various connectors to all of the others, it gets gradually smarter about that. Its little microprocessor brain also listens to the messages coming in through all of those connectors, and it remembers the Ethernet addresses of the equipment connected to each connector. It accumulates all of this information into a little table and after a while, it knows which of your Ethernet devices are wired to which of its connectors.

Thereafter, instead of mindlessly transmitting everything to everybody, it only transmits messages to the connectors that are appropriate. This will make your small network a little bit more efficient. The truth is, if your network is really small, you will never notice the difference.


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