a simple simple question about routers

Discussion in 'Computing and Networks' started by Meema, Apr 16, 2012.

  1. Meema

    Thread Starter New Member

    Apr 16, 2012
    I'm in my first year in university and I have Computer Communications course
    The teacher asked us to connect 3 LANs using routers
    Can I have one router that is connected to the three LANs ?
    or do I have to connect each LAN to its own router so I will have three routers ?

    note: we have to make the network using Microsoft Visio .
    Thank you in advance !
  2. Papabravo


    Feb 24, 2006
    No. You only need 2 routers to connect 3 LANs. Traffic will move back and forth from the LANs without a common router using the network connected to both routers as a bridge.
  3. Meema

    Thread Starter New Member

    Apr 16, 2012
    But the teacher said do not use bridge!
    Thank u.
  4. electronis whiz

    Well-Known Member

    Jul 29, 2010
    you only need one router. then your swithches or posibly hubs come off the router. the router then makes each a subnet using the number of bits the subnet mask specifys. each port out of the router will have a ip adress and the subnet on the switch or hub will get the network protion from that router port. such as if the subnet mask is for a class C adress the mask would be this means that the first 3 octets (the digits between the decimals =to 8bytes) will be for subnet then the nodes (divices on a subnet) will get adresses in that subnet like the router port will use an adress also probly like the first digit. that gives you 256 adresses however 0, 127 loopback, 255 brodcast adresses are not valid so you actily have 253 valid ip adreeses for nodes. then the trafic will be conected between the switches by 1 router. local trafic stays on its subnet, if going elswhare it goes throught the router and gets sent to the other subnet.
  5. c0de3

    Active Member

    May 1, 2009
    Correct, one router with 3 ports will connect 3 subnets together and route the traffic between them.
  6. Meema

    Thread Starter New Member

    Apr 16, 2012
    Mr. electronis whiz + Mr. c0de3
    u really helped me!
    Thank u!