keeping this as non-technical as possible...
A switch or a hub is something you would use on your LAN (local area network) to connect the comptuers in your home or office together to allow network printing, internet and file sharing, etc.
A SWITCH is more efficient as is it basically sends packets of data from one computer to another by sending the packet DIRECTLY to the port the other computer is located on.
A HUB sends data packets out to ALL of the ports and allows the computers to sort out the packets to determine which ones it needs, thus a hub can slow things down compared to a switch.
The term ROUTER is sometimes loosely used. Basically, it "routes" data from one location to another. In a corporate environment, you might use a router as the point of entry between multiple buildings. It acts as the gateway between multiple IP subnets on the WAN (wide area network)
In a home or small office, the term router usually means the firwall that connects your LAN to the internet. As opposed to allowing data to freely pass through it like in the corporate environment, it usually acts a one-way door, allowing traffic to flow OUT to the internet, but not IN to your network. This brings us to "firewalls"
FIREWALL and ROUTER are often times used incorrectly. When setting up an internet connection at your house, you want to purchase a router that has a NAT firewall (network address translation) and a DHCP (assigns LAN IP addresses) server built into it. These "built-ins" allow you to typically just plug everything together and almost instantly allow multiple computers to share one internet connection with a hightened level of secuirty and no need for an additional DHCP server, proxy servers, etc...
I hope this helped at least a little
