VLSM Subnetting

xkaijinx · June 2013

Working through some VLSM overlapping problems and I am going about it totally wrong. I cannot understand how I am so off on what the actual answer is..

Problem 1:
10.1.34.9/22
Subnet ID = 10.1.32.0
Broadcast Address = 10.1.35.255

My answer:
Subnet ID = 10.1.34.0
Broadcast Address = 10.1.37.255

Problem 2:
10.1.17.1/21
Subnet ID = 10.1.16.0
Broadcast Address = 10.1.23.255

My answer:
Subnet ID = 10.1.17.0
Broadcast Address = 10.1.24.255

dsgm · June 2013

Im trying to understand why your answer is off
Have you gotten your /22 /21 down properly a /22 is increment of 4, So your subnets would be 0,4,8,12...,28,32 so thats why the answer is Subnet ID 10.1.32.0 - 10.1.36.0 so the broadcast address would be 10.1.35.255 last valid address would be 10.1.35.254.

I hope this helps

theodoxa · June 2013

The address they're giving you is a random IP Address within that subnet. It is possible that some or [if they use a mask smaller than /8 which is unlikely] all of the octets may not be the same as those in the Subnet ID or Broadcast Address.

shabeerm · June 2013

Problem 1:

/22 means subnet mask will be 255.255.252.0 .So block size will be 4 and changes will be happening in 3rd octet.

10.1.0.0
10.1.4.0
10.1.8.0
10.1.12.0
10.1.16.0
.
.
.
.
.
10.1.28.0
10.1.32.0
10.1.36.0
.
.
.
Ip 10.1.34.9 will be coming in the network range 10.1.32.0 - 10.1.35.255

Problem 2

/21 means subnet mask will be 255.255.248.0 and block size will be 8.changes will be happening in the 3 rd octet

10.1.0.0
10.1.8.0
10.1.16.0
10.1.24.0
10.1.32.0
.
.
.

Here Ip 10.1.17.1 comes in the network range 10.1.16.0 - 10.1.23.255

Hope you get an idea now

VLSM Subnetting

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