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New Member

help on subnetting

I know how to work how how many hosts you can have when subnetting, but I want to know how many networks you can have ? can anyone help, i.e how many networks on a 255.255.248.0 mask ?

thanks

Carlos

  • Other Network Infrastructure Subjects
2 REPLIES
Purple

Re: help on subnetting

Hi Carlos,

I presume you mean the number of subnets when you refer to networks.

To work out the number of subnets, it is not enough to have just the subnet mask. You also need to specify the mask of the network address that you are trying to subnet.

For example, if you have a /16 network (255.255.0.0) which you wish to subnet using a 255.255.248.0 mask, then the subnet portion of the address would have 5 bits. Therefore, the number of possible subnets is 2^5 = 32.

Essentially, you find out the difference in bits between the length of the original mask and the subnetted mask and then calculate 2 to the power of the difference. In my above example, the initial network mask is /16 and the subnet mask is /21. Therefore, the difference is 5 bits, leading to a mask of 2^5 = 32.

Hope that helps,

Paresh./

New Member

Re: help on subnetting

Thats brilliant thankyou, can you give me a good another good example of the same, and how many hosts, and subnets you have worked out !!

thanks

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