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  • 70-291 Question

    Although I am revising for the 290 at the moment, I stumbled across this question and it has got me thinking - I really need to review my Network + material when moving on to the 291!

    Anyhow here goes;

    You administer a single active directory domain that consists of 2003 Server and XP clients.
    A server called ABR1 connects to AreaA. Another server called ABR2 connects to AreaB

    AreaA has a summarized route of 204.29.18.0/26
    AreaB has a summarized route of 204.29.19.0/27

    Identify valid subnets that can be used in AreaA and AreaB

    The correct answers are;

    204.29.18.64/26 and 204.29.19.192/27

    I have broken everything in to Binary, but think I missing something vital like the which subnets are valid within each network.

    Simon

  • #2
    Re: 70-291 Question

    With a 26 bit subnet mask, AreaA has 4 subnets (steal two bits from 4th octet)

    204.29.18.0 /26
    204.29.18.64
    204.29.18.128
    204.29.18.192

    With a 27 bit mask, AreaB has 8 subnets (steal 3 bits from 4th octet)

    204.29.19.0 /27
    204.29.19.32
    204.29.19.64
    204.29.19.96
    204.29.19.128
    204.29.19.160
    204.29.19.192
    204.29.19.224

    Are you sure the question does not involve variable length subnet masks and both in the 204.29.18.x network? Otherwise your posted answers do not seem to make sense

    Tom
    Last edited by Ossian; 16th January 2007, 23:17.
    Tom Jones
    MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
    PhD, MSc, FIAP, MIITT
    IT Trainer / Consultant
    Ossian Ltd
    Scotland

    ** Remember to give credit where credit is due and leave reputation points where appropriate **

    Comment


    • #3
      Re: 70-291 Question

      Originally posted by Ossian View Post
      Are you sure the question does not involve variable length subnet masks and both in the 204.29.18.x network? Otherwise your posted answers do not seem to make sense
      Tom,

      Thanks for your reply.

      There is no mention of VLSM in the question; the options are as follows;

      204.29.18.16/26
      204.29.18.32/26
      204.29.18.64/26
      204.29.18.96/26
      204.29.19.168/27
      204.29.19.176/27
      204.29.19.192/27
      204.29.19.208/27

      Comment


      • #4
        Re: 70-291 Question

        You'll notice from the choices that the only valid network addresses are 204.29.18.64/26 and 204.29.19.192/27. The rest could not be network addresses due to the mask they have.

        I don't know what they mean by "summarized route of 204.29.18.0/26." Is there some context that I'm missing?
        Regards,
        Jeremy

        Network Consultant/Engineer
        Baltimore - Washington area and beyond
        www.gma-cpa.com

        Comment


        • #5
          Re: 70-291 Question

          Jeremy,

          Originally posted by JeremyW View Post
          You'll notice from the choices that the only valid network addresses are 204.29.18.64/26 and 204.29.19.192/27. The rest could not be network addresses due to the mask they have.

          I am going to review the binary again for this.

          I don't know what they mean by "summarized route of 204.29.18.0/26." Is there some context that I'm missing?

          No. That is how the question is phrased.

          I didn't want to post a screen capture for copyright reasons.

          Thank you for your post.

          Simon

          Comment


          • #6
            Re: 70-291 Question

            Code:
            (into the host bits)
            204.29.18.16/26  = 11001100 00011101 00010010 00010000 
            	    Mask = 11111111 11111111 11111111 11000000
            
            (into the host bits)
            204.29.18.32/26  = 11001100 00011101 00010010 00100000 
            	    Mask = 11111111 11111111 11111111 11000000
            
            (valid network addr.)
            204.29.18.64/26  = 11001100 00011101 00010010 01000000 
            	    Mask = 11111111 11111111 11111111 11000000
            
            (into the host bits)
            204.29.18.96/26  = 11001100 00011101 00010010 01100000 
            	    Mask = 11111111 11111111 11111111 11000000
            
            (into the host bits)
            204.29.19.168/27 = 11001100 00011101 00010011 10101000 
            	    Mask = 11111111 11111111 11111111 11100000
            
            (into the host bits)
            204.29.19.176/27 = 11001100 00011101 00010011 10110000 
            	    Mask = 11111111 11111111 11111111 11100000
            
            (valid network addr.)
            204.29.19.192/27 = 11001100 00011101 00010011 11000000 
            	    Mask = 11111111 11111111 11111111 11100000
            
            (into the host bits)
            204.29.19.208/27 = 11001100 00011101 00010011 11010000 
            	    Mask = 11111111 11111111 11111111 11100000
            Regards,
            Jeremy

            Network Consultant/Engineer
            Baltimore - Washington area and beyond
            www.gma-cpa.com

            Comment


            • #7
              Re: 70-291 Question

              Once you compare the answers with the valid subnets I posted, you can see why only the two you gave are correct. If I had seen all the answers originally, it would have been clear.

              I think "Summarised Route" is another phrase for the 'slash' notation e.g. /26 I have seen it used for supernetting so why not for subnetting.

              Tom
              Tom Jones
              MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
              PhD, MSc, FIAP, MIITT
              IT Trainer / Consultant
              Ossian Ltd
              Scotland

              ** Remember to give credit where credit is due and leave reputation points where appropriate **

              Comment


              • #8
                Re: 70-291 Question

                Tom,

                Originally posted by Ossian View Post
                Once you compare the answers with the valid subnets I posted, you can see why only the two you gave are correct. If I had seen all the answers originally, it would have been clear.

                Yes. I should have entered them in the first post.

                I think "Summarised Route" is another phrase for the 'slash' notation e.g. /26 I have seen it used for supernetting so why not for subnetting.

                Thanks for clearing that up.

                Tom
                Thanks for your post.

                Comment


                • #9
                  Re: 70-291 Question

                  Originally posted by Ossian View Post
                  I think "Summarised Route" is another phrase for the 'slash' notation e.g. /26 I have seen it used for supernetting so why not for subnetting.
                  I was spending some time studying and I came across this.
                  http://www.ciscopress.com/articles/a...&seqNum=5&rl=1
                  I then remembered this thread and that I didn't know what it meant.
                  Definitely cleared up the "Summarised Route" terminology for me.
                  Regards,
                  Jeremy

                  Network Consultant/Engineer
                  Baltimore - Washington area and beyond
                  www.gma-cpa.com

                  Comment

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