VLSM example, ACME Inc

[woodyhoi2010]

may I know how many how to I calc this address?

given 172.20.12.0/22 with host of (site 1- 150, 100),(site 2 - 50), (site 3 - 35, 20), 2, 2, 2.

172.20.1100 0000.0000 0000

it shld be 172.20.12.0 to 172.20.206.0 or 172.20.206.0 to 172.20.207.0? or totally wrong?

[Keith6783]

@woodyhoi2010

You can verify your work, by using a calculator, like this free one:  wwwDOTvlsm-calcDOTnet

Replace the DOT with a "." in the URL.

[woodyhoi2010]

@Keith6783

thks very helpful site

[kxzyan]

Thanks for the quick reply...

[kxzyan]

how did you come p w/ 4 bit for 10 subnet, you said to get 10 subnet we need to take 4 bit out of the 3rd octect , what method did you use to figure that out quick.

I love all your videos. one more thing, when you have chance can you explain little about the acl , map , match set and vlan environment.

vlan access-map 20

match ip address STORE

action forward \

vlan filter pass vlan list 2-5

[Keith6783]

@kxzyan For quantity of hosts or subnets it is all about powers of 2. 2 to the power of 3, (3 bits) is only 8, and we needed 10 subnets, so we need to take 4 bits. With 4 bits, we can have 2^4=16 subnets: 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 etc, all the way to 16 possible combinations, (which equates to 16 possible different subnets) Best wishes, Keith

[mariana80929]

THANK YOU VERY MUCH!!!!!!!!!!!!! Finally I underestood, great explanation :)

[Keith6783]

@mariana80929

I am happy it was useful for you.  Thanks for the comments.

Best wishes,

Keith

[ucha19871]

Grate explanation

[paperkrain]

Awesome Vid. Studying CNNA atm and this is the most complicated part of the course. Hard to find clear examples like this one.

moar vids ! ! ^_^

[ManOfMeans]

@paperkrain I disagree.  I think learning IOS is more difficult than subnetting or VLSM