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TOPIC: Variable-Length Subnet Masks

Variable-Length Subnet Masks 5 years 8 months ago #36084

  • ping
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Hi,

I was reading about variable length subnet masks on one of the presentations from one site and I came across this particular site which contained some statements I was unable to understand.

The site was explaining about various possible VLSM assignments.

The slide had following content.
I would be very thankful if someone could explain how these assignments are carried out.


Title: Use Of Address Space (Start With 16 Bits Of Host Suffix)
    One possible VLSM assignment (92.9% of addresses used)
    11 networks of 2046 hosts each
    24 networks of 254 hosts each
    256 networks of 126 hosts each

    Another possible VLSM assignment (93.1% of addresses
    used)
    9 networks of 2046 hosts each
    2 networks of 1022 hosts each
    40 networks of 510 hosts each
    160 networks of 126 hosts each


Thanks...

Ping
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Re: Variable-Length Subnet Masks 5 years 8 months ago #36086

  • Chojin
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VLSM is a word for not using classfull subnets.

the 10.0.0.0/8 is a classful subnet, when using VLSM (that is variable length subnet masks) you can for example split the 10.0.0.0/8 up in multiple networks.


10.1.0.0/16
10.2.0.0/16
10.3.0.0/24
10.3.1.0/24

etc. This way you can make your networks smaller (or larger when supernetting) and adjust it to your needs.

Hope this sheds a bit of light :-)
CCNA / CCNP / CCNA - Security / CCIP / Prince2 / Checkpoint CCSA
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Re: Variable-Length Subnet Masks 5 years 8 months ago #36088

  • rizin
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Hi Ping,

On Which Class Address they want to apply those VLSM e.g A, B, or C, so that you will able to know the answer precisely.

Rizin
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Re: Variable-Length Subnet Masks 5 years 8 months ago #36089

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Thank You Chojin, the issues is clear now..
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Re: Variable-Length Subnet Masks 5 years 8 months ago #36090

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rizin, in the example I was reading it was referring to class B addresses..
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Re: Variable-Length Subnet Masks 5 years 8 months ago #36095

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thanks ping and it is sounding great that your issues had got cleared.
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