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Setting up a wired sub-LAN

By wolfram
Feb 22, 2010
  1. Hi everyone,

    Today I was asked to setup a small network for a classroom. I need to network 4 computers and share a single printer. They also need Internet access (this is where it gets tricky for me).

    I was thinking a simple switch would do the job (sharing the printer and networking the machines), but what about the Internet? A single UTP cable coming from another classroom brings the Internet here (this cable is connected to a 48-port switch, which is connected to a 2 wire modem/router provided by the ISP).

    So do you think I could just use that cable, connect it to the switch and configure it to share the Internet? I hope I explained this good enough :eek:

    Thanks =)
     
  2. jobeard

    jobeard TS Ambassador Posts: 9,315   +618

    let's try to get a map of what you have:
    Code:
    isp --- modem/router---48port.switch-->classrooms
    and one of the 48 comes to you, right?

    you have ONE port on the switch, but need four systems to share it. That will require your
    modem/router to support more that 48 connections, ie the DHCP service it provides needs more that 48 addresses.

    The for-sure solution is to take
    Code:
    48port.switch-->your.classroom->new.router
    this will isolate your classroom from the other 47 connections but still allow Internet connectivity.

    Attach your printer to ONE of your four systems and use Print/File Sharing for your class use. (the other classrooms will not see you at all.)
     
  3. wolfram

    wolfram TechSpot Paladin Topic Starter Posts: 1,967   +9

    Hey thanks for your response!

    The map you made is correct. Yes a wire coming from the 48 provides internet to the teacher's PC. That's where I want to place the switch/router, so the other machines can have Internet and normal networking. (turns out I'll probably need to connect 5 PC's)

    The modem/router is a 2wire 1070. Do you think that would have enough addresses? I'd think it would support at least 100, but I really don't know.

    Thanks for helping me to clear this mess out :) (I'm a newbie at networking lol)

    I made a quick drawing in word to explain what we have:
    [​IMG]
     
  4. jobeard

    jobeard TS Ambassador Posts: 9,315   +618

    Using the 8-port switch would allow
    all the students in your class to see every other system
    and all the systems in the school to see/access your classroom​

    The 48port switch in your drawing (normally) does not support DHCP service;
    it (DHCP) would have to come from the modem in front of it

    Place a NEW 4-port router ($49) of any make (suggest NOT wirless) between the 48port switch and your 8port ENH908;
    it will support the DHCP for your classroom only, have 3 user ports and the 4th to attach the ENH908
    AND isolate your class from all other classes and vise-a-versa

    You can cable the classroom systems anyway you like.

    Tip: if the ip address coming into your room is 10.x.y.*, then set your new router to
    have a router IP address of 10.x.y+10.1

    When you're ready for the install, we can complete the config ...

    Jeff
     
  5. wolfram

    wolfram TechSpot Paladin Topic Starter Posts: 1,967   +9

    Hi again,

    I'm aware the 48 port switch (which is in another classroom) does not support DHCP. I believe the 2wire 1070 modem/router provides DHCP support (I had one in the past and it did provide DHCP), that's why I was thinking it could simply assign an IP to these new machines.

    I'm trying to keep all this as cheap as possible, so do I really need a router? This would be so easy to setup if they had dedicated Internet service in their own classroom.........

    Thanks! =)
     
  6. jobeard

    jobeard TS Ambassador Posts: 9,315   +618

    you would need a router to isolate your class from the school per se and if that's not required,
    then the modem should be able to provide four more addresses :) just add the switch.
     
  7. wolfram

    wolfram TechSpot Paladin Topic Starter Posts: 1,967   +9

    Hey man thanks a lot for your help, I'm posting this from the new network =)

    Thank you a lot!
     
  8. jobeard

    jobeard TS Ambassador Posts: 9,315   +618

    Bravo -- well done :)
     
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