4 Replies Latest reply: Mar 19, 2012 11:13 PM by RG_WB RSS

    Network ID or Subnet ID

    Gav

      Hi Everybody,

       

      I have a really daft question for you all.

       

      I have just taught myself subnetting which I am fine with, but whilst practicing on various questions I see the answers refering to both Network ID and Subnet ID.  Are these two terms interchangable or Is there a difference, if so what is it?

       

      Many Thanks

        • 1. Re: Network ID or Subnet ID
          Stephen

          In the real world, people use them interchangably (this is the way I've always looked at it).  I guess the real definition comes in where you talk about classful and classless networking (as this is where CIDR/subnetting was involved).  So a class C 192.168.0.0/24 address would be a network.  If we were to subnet it, lets say we want to have 8 subnets, we would have

           

          192.168.0.0/27

          192.168.0.32/27

          192.168.0.64/27

          192.168.0.96/27

          etc...to

          192.168.0.224/27

           

          Each of these subnets would be part of the major classful network of 192.168.0.0/24.

           

          But the word subnet and network are used interchangably

          • 2. Re: Network ID or Subnet ID
            Martin

            I agree, but I would use terms properly for exam study and during exam.

            Address could have 3 parts if subnetted: network, subnet, host portions.

            • 3. Re: Network ID or Subnet ID
              Gav

              Stephen, thanks for that, it makes perfect sense.  Martin, your right, I need to learn the correct terminology for the exam, I'm finding that even though I know the answer to questions I am making silly mistakes and getting them wrong - its just like learning to pass your driving test.

               

              Thanks for your help

              • 4. Re: Network ID or Subnet ID
                RG_WB

                What's up GAV,

                 

                In support of Stephen's and Martin's answers and for your exam terminology reference,  CH 12 pg 263, 640-822 OCG  3rd ed. The key topic says subnet number is also called subnet ID or subnet address...numerically the smallest number in the subnet and cannot be used by a host,  just as Stephen pointed out

                 

                192.168.0.0/27

                192.168.0.32/27

                and so on...

                 

                with .0 and .32 being the subnet ID