And besides, u asked why is it better with router. Well, if u have already a computer which runs 24/7, then u dont realy need one. DSL/Cable routers works a little different, since u only have one IP, so they use NAT to share your net. NAT is a thing what u can do easily with a computer also. So, if u dont want your main computer to be turned on all day long, u have 2 options: building a linux box(on a cheap hardware, since nat doesnt need too much resourche) to share the internet, or u can buy a router, which is a special "computer" designed for networking tasks.
So, if u have some old comp. part, or u can get one cheap, thats perfect for u, provided u have the knowledge to install a linux with NAT support. DSL/Cable routers beacme very cheap, and the good thing is that, u dont have to have the knowledge to install it (howover this can be a downside also... you cant adjust it as fine as a linux (well, as for the cheaper routers ^_^))
If u decide to runn your main computer consider 2 things: it use much more power than a router, and since thats the computer that u work with or play with , its most likely to freeze, or u must reset it... not wery good thing from the other computers user's aspect
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And some theory:
HUB ans Switch works on Layer 2, in the TCP/IP modell, which means they only knows about your Devices NIC adress. HUb is a "dumb" device, if it got something on one port, it broadcasts to each other, and to select which data is for which device, thats the device's task. Swich is a lil bit smarter, sinc it "knows" which equipment has which NIC adress, and only sends the date to it. So with switch u can utilize bandwith in a better way.
As for Router, they are intelligent devices, they are "route the data flow" in your network. So for example based on the IP adress, they decide which network to send and they can do a lot more thing. For sharing your net u need a Router (DSL/Cable).
Note: Sometimes u can see ppl atachin their DSL modem to a switch. Thats not Net share! Since DSL modems has ethernet interface u can utilize it with switch als, so u can connect with PPPoE drivers from multiple computers. Thats not a net share.Of course this setup can be used to share net in the way we talking about, with a computer runing NAT. But anyway i dont want to mix it up for u
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