A layman's definition of hubs, routers, switches

Posted on 2005-05-16
Last Modified: 2013-11-29
Dear Experts,

I recently bought 12 computers (bulk sale). I have a broadband connection (DSL) and I'd like to network them so they can access the Internet at the same time because I'm planning to set up a computer shop.

The setup fee of my ISP is skyrocketing so I'm thinking of setting it up myself. I did a search on the Internet and I had to wade through jargon I didn't know even existed. Articles kept talking about hubs, switches, routers, etc... (My ISP set up my connection for me and I just left them alone since I didn't understand what they were sticking into my machine)

I have a feeling I'll be using one of these, so can anyone please tell me what I need to do to get my network running and connected online? The most minimal setup will do for me.

Thanks in advance!
Question by:jericotolentino
    LVL 95

    Assisted Solution

    by:Lee W, MVP
    Need to know what kind of internet connection you have - T1, DSL, Cable, something else?

    Typically, a router, as most non-technical people think of them, performs something called Network Address Translation and doubles as a hardware firewall.  Basically, The internet connection plugs in to the Router's "WAN" (Wide Area Network) port - and the router creates a private network that all your local computers connect to.  As far as your ISP is concerned, you have one address.  But you could have 65,000 computers or devices needing IP Addresses.

    A hub takes one connection and adds more ports to the network so you can add devices.

    A switch does the same thing as the hub, only it's more intelligent.  Switches "remember" the electronic serial number (MAC Address) of the computers connected to it.  As a result, it can match IPs and MAC addresses and more efficiently route data to computers.  a 100 MBit hub is limited to 100 Mbit upload and download combined.  A switch can do 100 MBit Up and 100 MBit Down at the SAME TIME (double throughput; maximum in any one direction is 100 MBit).
    LVL 7

    Accepted Solution

    I presume you only had one computer before.
    Since you have a DSL connection, your ISP likely gave you a DSL modem - it only has one connection for a computer, is that correct?

    So you need to get a router - there are many good small-office/home-office (SOHO) routers out there.  Some well known brands are Netgear, D-Link, Hawking, Linksys.  These typically have about four ports for connecting computers to them. This is basically a built-in four-port switch.

    You can also buy a small switch, connect one of its ports to one of the router ports, then connect the rest of your new computers to the switch.  Are you by any chance in the Silicon Valley area?  If so, I can help directly.

    In any case, while leew is correct that a switch is more intelligent than a hub, the real differnce is different (ha!).
    Using a hub, all the devices connected to it see all traffic.  But a switch, being more intelligent, sends traffic only to those devices that it is addressed to.

    If the switch is designed for full-duplex operation, and the device attached to it is also designed for full-duplex operation, then it is possible for the switch to double the throughput on a particular channel.  But both the switch and the device on that channel must not only be designed for full duplex - both must actually be set up to use it.

    Anyway, here is a picture to make things clearer (diagrams always make thngs clearer, don't you think? I don't know why people don't use them more.)

    Here is what I think you originally had:

    Internet< -------->ISP<------>DSL Modem<-------->One computer at your home

    Here is what you will have (assuming you have a switch with 12 or more ports, plus one to go to the router)

    Internet<---->ISP<---->DSL Modem<------>Router
                                      /                    /          \              \
                                    /                    /             \              \
                             computer1   computer2 .... computer11  computer12
    LVL 1

    Expert Comment

    An interesting idea is that you can make your first computer to share its connection with all the other computers.
    How you go about that is simple...

    Step 1: get a 16 port switch. Switches are intelligent devices which can control the broadcasting of traffic which is good :)
    Step 2: connect all your computers to the switch via ethernet cables (straight patch chord)
    Step 3: enable connection sharing of you DSL connection. For doing that you right click on the connection, goto properties, then goto advanced and there check "allow others to share this connection". windows will ask to set the IP address of your ethernet interface to, accept that.

    Make sure that you have all your computers set to "obtain ip address automatically"

    As for the hubs and routers.
    Hubs are just regenerators....they just reproduce the electrical signals on all ports
    Routers are used when you want to connect different logical networks. In the case above, your windows machine will be acting as a router.....just to save money :)

    LVL 5

    Author Comment

    Thanks! leew's explanation and the diagram really cleared things up.

    > Need to know what kind of internet connection you have - T1, DSL, Cable, something else?

    I have a SDSL connection. I think it's 1Mbps. I don't know if that's fast or slow, but it's fast enough for me.

    > I presume you only had one computer before. Since you have a DSL connection, your ISP likely gave you a DSL modem - it only has one connection for a computer, is that correct?

    Yes, only one computer. My DSL modem was given by my ISP also. I'm planning to upgrade my plan because my ISP will allow only 2 more computers to be connected to a single computer.

    Please correct me if I am wrong, but in the diagram CajunBill drew, I assume that there is only one DSL modem. Does this mean I can use regular LAN cards and plug their cables into the switch?
    LVL 5

    Author Comment

    Whoops, I missed sohaibfaruq's post. Sorry.

    I think that's what I'll probably do. But I'll probably get a router too, as leew said that it'll help with security as a firewall. I don't think I'll be under any attack, but I guess it's better to be safe than sorry. :-)
    LVL 7

    Expert Comment

    Yes, jerico, a SOHO router would be good.  These days they typically come with wireless also - the non-wireless ones are almost being given away.

    Yes, you "use regular LAN cards and plug their cables into the switch?".

    As for "my ISP will allow only 2 more computers to be connected", with the router they won't see it as multiple computers - most routers will do what used to be called PAT by Cisco: that's the NAT mentioned by leew.  The only reasons to upgrade your ISP plan are:
    - to get more bandwidth (you might need it with 12 computers)
    - to get a static IP address instead of the usual dynamic IP
    - to get multiple static IP addresses, if you want the outside world to connect to more than one of your computers

    Otherwise there is no reason they should know or care how many systems you have.
    LVL 5

    Author Comment

    Oh, I see. I was thinking I might get into trouble by connecting all twelve computers to the one with the DSL modem. But I think I'll still upgrade the plan due to the bandwidth issue.

    Thanks for the help everyone! It sure is easier to figure things out now. Time for me to get to work. :-)

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