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Subnetting question(dealing with Hosts)

KGhaleonKGhaleon Member Posts: 1,346 ■■■■□□□□□□
I've seen this question in tests numerous times, and I'm sure it's shown up on exams better(not the exact question), so I'm wondering how your suppose to solve this type of question quickly.

Your subnet mask is 255.192.0.0, you know that there are 10 network bits and 22 remaining host bits. The question asks you how many hosts are available to use(ignore subnet zero).

Now we all know the solution to this would be to take 22^2 to find the answer...but when your taking the CCNA or similar exams, how do you do this fast enough when you only have paper? :P

(Assuming I did that correct, it's been a while)

KG
Present goals: MCAS, MCSA, 70-680

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    wastedtimewastedtime Member Posts: 586 ■■■■□□□□□□
    I had that table mostly memorized that was the easiest way for me. An don't forget it would be 22^2 - 2 because of the broadcast address and network address.
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    JiggsawwJiggsaww Member Posts: 195
    whoa.......i hope i dont get ah ques like that
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    bbel121bbel121 Member Posts: 7 ■□□□□□□□□□
    Here is a pretty good page that breaks it down for you...it is dedicated to subnetting

    http://www.thebryantadvantage.com/TheBryantAdvantageMasterySeries.html

    John
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    evanderburgevanderburg Member Posts: 229 ■■■□□□□□□□
    I have up to 2^20 memorized because you encounter it in all kinds of IT situations but anything higher than that and I just double it a few times.
    "You can never know everything and part of what you know is always wrong. Perhaps even the most important part. A portion of wisdom lies in knowing that. A portion of courage lies in going on anyway. " - Lan, Winter's Heart by Robert Jordan
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    wastedtimewastedtime Member Posts: 586 ■■■■□□□□□□
    Heh, just noticed I wrote it backwards up there should be 2^22.
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    suprchgtntsuprchgtnt Member Posts: 12 ■□□□□□□□□□
    learn binery- super simple and you can do it in your head
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    AhriakinAhriakin Member Posts: 1,799 ■■■■■■■■□□
    2^10=1024, easiest for me to remember (ie. To the power of 10 is the nearest to 1000) if you're dealing with 20+ then multiply 1024x1024= 2^20, then just multiply by what ever is left (eg. 2^22 then do 1024x1024x4 (Since 2^2 is kinda easy :) ), just break it into workable subsets. Still some math involved vs. memorisation but it's simpler and faster imho.

    WastedTime - Edit. NM...Im an idiot and was thinking subnets.
    We responded to the Year 2000 issue with "Y2K" solutions...isn't this the kind of thinking that got us into trouble in the first place?
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