hubs, routers, and switches OH MY!

[Nick Burns]

Can someone explain the difference between these three and when it is appropriate to use which one?
Also, is there a product out there that has like a 4 port switch and connects it to a wireless network to connect to a router with the DSL connection in it? This is for my future folding farm.

[Huckleberry]

Routers - use between your own network and sombody else's network (like your ISP's)

Hubs - connect computers on your lan. Older technology.

Switches - connect computers on your lan. Smarter (therefore faster) than hubs.

There is some confusion in that some routers include their own integrated hub or switch - thus they serve a dual purpose.

[wquiles]

A hub allows computers to connect to each other. It simply replicated packets from one source to ALL other ports, iregarless of where is the packet destined to go. Most small routers for home use come with a built in hub, so you need nothing else.

A switch is more inteligent and looks at the MAC address of the destination and only forwards the packet to that port, not all of them. So, with a switch, you could have 4 computers (A, B, C, D) and if A is sending data to B, C and D could be sending data to each other at the same time and traffic from A/B would NOT block/affect/slow down traffic from C/D. This non-blocking ability of a switch makes it better suited to scenarious in which you don't want traffic between some computers slow traffic with other ones. A hub is basically "dumb" so all computers connected to it get affected iregardless of the destination. Some small home routers have a switch built-in instead of a hub, but most likely you will never need the switch - a hub will be fine.

A router is more sofisticated since it looks at the IP address of the packets (OSI layer 3 - the switch is looking at layer 2 on the OSI model). Based on that address it decides where to sent packets to. In a home LAN, if you have more than one computer on the LAN sharing an Internet connection, you NEED a router so that it can "share" the one IP address of your internet connection with the local addresses assigned to each of the computers in the LAN (typically by DHCP, although they could be manually assigned as well).

So what do YOU need: If you want to share an internet connection with two or more computers you NEED a router. You also need a hub/switch (many times integrated with the router) with enough ports for each computer in your LAN. For 90-95% of folks, you only need a hub, not a switch. Small home routers from D-Link, Netgear, and Linksys would be perfect for setting up a home LAN and sharing an internet connection.

This is one of the MANY links in the Internet that does a better job at explaining this (just do a search on Google):
http://www.practicallynetworked.com/networking/bridge_types.htm

Good luck :)

[su root]

^^^ What they said, and:

A router is just a regular switch, except for you'll notice that they tend to be 1 port less than most switches. (they come in 4's or 7's, where switches usually come in 5's or 8's).

That extra port is used for a tiny internal computer, which has a firewall and does NAT (Network Address Translation) functions.

NAT is when you only have one IP address, so you put one computer (the router) as the holder of the IP. The router takes requests from computers on the LAN for information from the internet, uses it's real IP to fetch the requests, and returns the results to the computer that asked for it.

[Nick Burns]

I have my downstairs hard wired to the back of the linksys 802.11G router. Then, my upstairs computer connects wirelessly with a PCI card. The farm I will be building is upstairs next to the computer connected wirelessly. How do I share the internet connection with the farm without needing to spend all of the money on PCI cards or individual ethernet adapters. Is there a product that is a switch and then it connects to a wireless network or something like this? Could I hook up a wired router to take internet access from the main computer with the PCi card and then hook the farm computers into it? Or am I forced to buy individual wireless PCI cards?