Hub, Router, Switch — Which?

Got an hour of detailed training last night on IP networking. I’m not an expert and it’s not my field. However, I now have simple definitions for hub, switch and router. These are terms that I did not understand as a home networking product user, not to mention being exposed to them at the office.

I had tried to clear up the meanings (and differences) of these words in the past to no avail. Here’s my understanding as of last night (thanks, Brad):


A hub sends each packet to every node on the network. Traffic on hubs can easily get clogged if two machines are sharing large amounts of information with each other since every single packet goes to every single machine. As a rule of thumb (just a loose estimate that I requested of my trainer) once you’ve got five computers on a hub, you’ll notice a speedup when you move to a switch.


A switch is an upgrade (a big one) from a hub. According to my trainer, switches have come down so far in price it almost doesn’t make sense to waste your money and time on a hub. A switch routes from MAC address to MAC address on the network. It does not send each packet to every node. Switches are fast. But they’re not routers (and neither are hubs).


A router connects two networks. For example, if you have a cable modem in your home and you share that internet connection with more than one computer via some Linksys|Netgear|DLink “box” that box should be a router. It connects your private [home] network to the external network — the internet.

Network-connection-sharing Routers

To understand how your router allows all your computers to use your single internet connection and its one IP address you should understand that:

– It is a router. It connects networks.

– When a computer sends a request packet to a website, it includes a request regarding which port (> 1024) to return the response on. The router then sends this request into the “real world” and gets a response on the same requested port that the client machine requested. With this >1024 (somewhat random) port number and the client’s private IP address, the router knows how to get each response packet back to the correct computer on the private network.

I hope I got that last part right.