Class B Subnetting

Class B Subnetting

our host address is 160 dot 25 or dot 67 200 I have a 19 bit mask so we got 19 bits of subnetting for the subnet mask we can start off with 255 255 since we know that 16 binary bits to get from 16 to 19 we need three so tick down three and that'll give us the subnet mask of 224 dot zero and since we've ticked down three we need to take across the top three places to get increments of 32 so we can start off with a zero subnet well I need to put the last two octets in 30 20 60 40 we can carry on going up in increments of 32 we didn't go too far though however because we're looking for hosts number 67 dot 200 because we're subnetting on the third and fourth octet so clearly we have the answer now we could actually write out 160 24 dot 60 40 as the answer and move across to the next question if in the exam they asked us what the first toast on last toast is is pretty easy to work out we had one in the last octet for the first toast to get the broadcast will take one away from the next subnet and then to get the last toast we take one away from that so we have the answer now you


  • James Dinser says:

    Your host range for the 3rd subnet should be 64.1 to 94.254 which gives you 30 actual useable host per subnet. Your increment is 32 and then you subtract 1 for the network and 1 for the broadcast and you get 30 host.

  • A says:

    After a break from subnetting for a few weeks I found this video ideal at reminding me the process involved with subnetting a class B address. Well done! I relearnt the process in under two minutes.

  • michelle_pie says:

    Thank you!

  • junebug83 says:

    Wow… I've always been close to understanding subnetting properly but, never fully understood until watching your series!! In spite of the different ways my instructors has all taught it, this one really clicked.

    Thank you sooooo much for posting!! I don't think I'll fail my exam tonight because of you 🙂

  • Brad Moses says:

    thanks, made things easier and can now subnet properly!

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