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Slaks
Joined: 19 Jul 2004
Posts: 1
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 Posted: Mon Jul 19, 2004 11:03 am Post subject: Subnetting issue |
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I have a problem with Subnetting question in my exam on Networks and i am currently trying to prove that the answer to the question is incorrect
The question is :
Suppose you are given an network ip adress 128.20.224.0/20
and asked to subnet this network into two subnets by allocating 1000 computers for first subnet and 750 for the last
And the answer is :
First of all - this network ip is one of 14 subnets of the network 124.20.0.0 ( classs B), it means that the network 124.20.0.0 was subnetted and now i need to subnet one of subnets, but using the algorithm of standard subnetting 2^n - 2 = number of subnets desired.
Now, I am not agree with that because the standard subnetting deals with division of the networks of class A,B,C and not of their subntes.
And there is another algorithm for recursive subdivision of subnets which is called VLSM, where i allocate bits for sub-sub-nets according to my need ( 2^n = number of subnets )
Am i right?
Slaks |
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Steve_2004
Joined: 14 Sep 2004
Posts: 1
Location: Singapore
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| Posted: Tue Sep 14, 2004 4:05 am Post subject: Re: Subnetting issue |
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| Slaks wrote: | I have a problem with Subnetting question in my exam on Networks and i am currently trying to prove that the answer to the question is incorrect
The question is :
Suppose you are given an network ip adress 128.20.224.0/20
and asked to subnet this network into two subnets by allocating 1000 computers for first subnet and 750 for the last
And the answer is :
First of all - this network ip is one of 14 subnets of the network 124.20.0.0 ( classs B), it means that the network 124.20.0.0 was subnetted and now i need to subnet one of subnets, but using the algorithm of standard subnetting 2^n - 2 = number of subnets desired.
Now, I am not agree with that because the standard subnetting deals with division of the networks of class A,B,C and not of their subntes.
And there is another algorithm for recursive subdivision of subnets which is called VLSM, where i allocate bits for sub-sub-nets according to my need ( 2^n = number of subnets )
Am i right?
Slaks |
Based on the query with regards to VLSM, i believe that the formula 2^n - 2 still applies cause there minus 2 which is for unusable zero subnet and broadcast (which is the first and the last)...... but now i believe we can enable the use of zero subnet by typing in the command ip subnet-zero in the routing configuration command |
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