Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements
Webcast-Catalyst9k
New Member

vlsm

Hi Friends,

I want know how to utilize "VLSM subnet Calculator"

plz. find the below infor.

How to use: Enter major network address and mask in slash-format, like 192.168.1.0/24

Enter sizes (number of assignable ip addresses) of subnets to divide major network. You can specify subnetwork names instead of default.

You can change number of subnets at any time.

What is the size of subnet?

For more clarification plz. find the attached file "vlsm calculator.doc"

Regards,

Naidu.

4 REPLIES

Re: vlsm

Size is referring to how many ip addresses you want in each network to be available.

Hall of Fame Super Blue

Re: vlsm

Size of subnet is how many hosts you want to be able to use in that subnet.

So if you needed 3 subnets from 192.168.1.0/24 with the following

subnet 1 will have 100 pc's

subnet 2 will have 50 pc's

subnet 3 will have 20 pc's

192.168.1.0 255.255.255.0 = 254 host addresses available ie.

192.168.1.1 -> 254, broadcast 192.168.1.255

You need 100 pc's for subnet 1 so

192.168.1.0 255.255.255.128 = 126 host addresses 192.168.1.1 -> 126, broadcast 192.168.1.127

Next you need 50 pc's

192.168.1.128 255.255.255.192 = 62 host addresses 192.168.1.129 -> 192.168.1.162, broadcast 192.168.1.163

Finally you need 20 pc's

192.168.1.192 255.255.255.224 = 30 host addresses 192.168.1.193 -> 192.168.1.222, broadcast 192.168.1.223

So the subnet sizes for your requirements are

subnet 1 100

subnet 2 50

subnet 3 20

Jon

New Member

Re: vlsm

sorry jon but i think you made a mistake on your second subnet vlsm ip addressing:

"Next you need 50 pc's

192.168.1.128 255.255.255.192 = 62 host addresses 192.168.1.129 -> 192.168.1.162, broadcast 192.168.1.163 "

if we consider we need 50 host addresses i think you meant:

192.168.1.128 255.255.255.192 = 62 host addresses 192.168.1.129 -> 192.168.1.190

broadcast 192.168.1.191

if you don't mind....

thanks.

Hall of Fame Super Blue

Re: vlsm

No need to apologise - i got my maths a little bit wrong :-).

You are quite correct, thanks for correcting. Rated accordingly.

Jon

224
Views
5
Helpful
4
Replies
CreatePlease to create content