What is the new Subnet Mask and what is the Increment? - ProProfs Discuss
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What is the new Subnet Mask and what is the Increment?
Subnet the Class B IP Address 130.13.0.0 into 500 Subnets. 

This question is part of CCNA Subnetting Quiz
Asked by AP_Jake, Last updated: Oct 23, 2020

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5 Answers

erijosh

erijosh

erijosh
Erijosh

Answered Aug 30, 2018

Subnet Mask 255.255.255.128 with an Increment of 128

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John Adney

John Adney

John Adney
John Adney

Answered Oct 22, 2017

Last octet being .10000000 = 128. Block size: 256-128=128. Increment of 128

Borrowing 9 bits in a class B IP results in third octet all being 1, and first bit in fourth octet being 1. Therefore the final subnet mask is: 11111111.11111111.11111111.10000000 or 255.255.255.128 or /25.

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Michael_66

Michael_

Michael_66
Michael_

Answered Jul 20, 2017

Agreed.

Last octet being .10000000 = 128. Block size: 256-128=128. Increment of 128

Borrowing 9 bits in a class B IP results in third octet all being 1, and first bit in fourth octet being 1. Therefore the final subnet mask is: 11111111.11111111.11111111.10000000 or 255.255.255.128 or /25.

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pinstrypsoldier

pinstrypsoldier

pinstrypsoldier
Pinstrypsoldier

Answered Mar 24, 2017

Agreed. 9 bits needed for 512 subnet (2^9=512). 16 bits available - 9 leaves 7 bits for hosts.2^7=128

Class B has a mask of /16,plus the 9 bits required for networks makes /25 or 255.255.255.128
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John Smith

John Smith

John Smith
John Smith

Answered Sep 24, 2016

Subnet Mask 255.255.255.128 with an Increment of 128

130.13.0.0 Need 500 Networks 128 64 32 16 8 4 2 1 . 128 64 32 16 8 4 2 1 0 0 0 0 0 0 0 1 . 1 1 1 1 0 1 0 0 = 500 in binary Need to borrow 9 bits for # of Networks New Subnet Mask = 255.255.11111111.10000000 (255.128) or /25 ^ Increment = 128 2^9 = # of Networks = 512 2^7-2 = # of Hosts per Network = 126 First 5 IP Ranges 130.13.0.0 - 130.13.0.127 13.0.128 13.0.255 13.1.0 13.1.127 13.1.128 13.1.255 13.2.0 13.2.127
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