MY CCIE JOURNEY

200.100.20.0

9 subnets

each host needs atleast 10 hosts



class c addr ..so subnet mask is 255.255.255.x

now we need 9 subnets .. tick in the subnets coloum till we meet the requirement of 9 subnets ...

so look at the table .. we have ticked 4 of them .. so tick 4 bits in the upper subnet table

it stopped at 240 so our subnet mask is 255.255.2555.240

now we are left with 4 empty bits (248 , 252, 254 , 255) tick them under hosts ... and subtract two we are done

the crucial one


bits------------128--------64--------32-------16-------8------4------2------1
subnets


128-----------------*

192----------------*

224---------------*

240------------------*

248

252

254

255


powers of 2 ------ subnets-------------------hosts (-2)

2------------------------*---------------------------*

4------------------------*----------------------------*

8-----------------------*-----------------------------*
we have met the requirement of 9 subnets
16-----------------------*-----------------------------*(16-2 = 14 hosts )

32

64

128


256


512


1024