Vlsm

suarez

Hi Gurus,I am stuck with this VLSM question where given the base address is 10.1.0.0/23:Required: 1) 6 hosts x 7 subnets2) 2 hosts x 6 subnetsCan anyone cast some light on me especially the second network?Thanks

Freestuff212

So with a /23 mask how many networks and hosts do you have? If we count it out 11111111.11111111.11111110.00000000. Rather then telling you the answer, I will ask you. What is your block size?

suarez

Hi, the block size of /23 would be 256 - 248 = 8. Is that correct?

Thanks

EdTheLad

suarez wrote: »

Hi Gurus,I am stuck with this VLSM question where given the base address is 10.1.0.0/23:Required: 1) 6 hosts x 7 subnets2) 2 hosts x 6 subnetsCan anyone cast some light on me especially the second network?Thanks

Your base address is 10.1.0.0/23 , what does that mean?
Well it means you have a usable address range from 10.1.0.0 - 10.1.1.255

So for 1 and 2, you pick whichever you prefer to solve first.

2) need 2 hosts, so i'll choose a /30 , need 6 subnets? so i'll choose 6 /30's

10.1.0.0/30
10.1.0.4/30
10.1.0.8/30
10.1.0.12/30
10.1.0.16/30
10.1.0.20/30

1) need 6 hosts 2^3-2 = 6 , 3 bits 32-3 = 29; /29 = 255.255.255.248
So now i have to choose my start point for the /29 subnet, i could start at 10.1.0.24/28, which would be my first block of 8 available i.e. 0,8,16,24... but i might need to add tome additional /30's later so i'll leave some room for them.
I'll start at 8,16,24,32,40,48,56,64... 64

10.1.0.64/29
10.1.0.72/29
10.1.0.80/29
10.1.0.88/29
10.1.0.96/29
10.1.0.104/29
10.1.0.112/29

All done, now i expect if there is any part of this you don't understand, you will go to google and do some research!

Freestuff212

Ed spelled it out nicely. Subnetting is one of those things you have to practice, and practice a lot. But once you get the concept it's pretty easy. It's just all about the requirements of the network and doing math.

suarez I would suggest re-reading the chapters, checking out youtube and Subnetting Practice Questions (for practice). At first it doesn't matter how long it takes you to get the right answer (as long as it correct), but you should get quicker and quicker at it.

suarez

Thanks guys for all the help and replies