ccna subnetting
sachinsharma
Registered Users Posts: 1 ■□□□□□□□□□
in Network+
Hi everyone ,
Could anyone please tell me why do we need to subtract 2 while creating a sunetting like for ex(255.255.255.192=2^6 hosts and no.of subnet are 2^2-2=2)
Could anyone please tell me why do we need to subtract 2 while creating a sunetting like for ex(255.255.255.192=2^6 hosts and no.of subnet are 2^2-2=2)
Comments
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redgunner
Member Posts: 42 ■■□□□□□□□□
You always need a beginning, a range and an end
Let's look at a very simple to understand network (class c)
Okay let's pick a random host IP!!
Hostname: 192.168.1.64
11000000.10101000.00000001.01000000
Mask: 255.255.255.0
11111111.11111111.11111111.00000000
Let's find our Start Range and End Range (known as subnet and broadcast)
(The bold represents our network portion and the underline represents our host portion)
Subnet: 192.168.1.0
11000000.10101000.00000001.00000000
Broadcast 192.168.1.255
11000000.10101000.00000001.11111111
Okay so the range is 192.168.1.1 to 192.168.254
In this very basic example you can see you have 254 hosts in this 1 subnet.
Let's look another example
Subnet: 192.168.1.0
Mask: 255.255.254.0
Broadcast: 192.168.1.255
So this means you can have a range from 192.168.0.1 - 192.168.1.254 which is 510 hosts
Remember you need a beginning and an end!! (subnet and broadcast)
Imagine it ranging from 192.168.0.1 to 192.168.254.254 (It still only has 1 subnet and 1 broadcast)
Hope this makes sense -
AndersonSmith
Member Posts: 471 ■■■□□□□□□□
You always need a beginning, a range and an end
Let's look at a very simple to understand network (class c)
Okay let's pick a random host IP!!
Hostname: 192.168.1.64
11000000.10101000.00000001.01000000
Mask: 255.255.255.0
11111111.11111111.11111111.00000000
Let's find our Start Range and End Range (known as subnet and broadcast)
(The bold represents our network portion and the underline represents our host portion)
Subnet: 192.168.1.0
11000000.10101000.00000001.00000000
Broadcast 192.168.1.255
11000000.10101000.00000001.11111111
Okay so the range is 192.168.1.1 to 192.168.254 In this very basic example you can see you have 254 hosts in this 1 subnet.
Let's look another example
Subnet: 192.168.1.0
Mask: 255.255.254.0
Broadcast: 192.168.1.255
So this means you can have a range from 192.168.0.1 - 192.168.1.254 which is 510 hosts
Remember you need a beginning and an end!! (subnet and broadcast)
Imagine it ranging from 192.168.0.1 to 192.168.254.254 (It still only has 1 subnet and 1 broadcast)
Hope this makes sense
Couldn't have said it any better!All the best,
Anderson
"Everything that has a beginning has an end" -
Attempted Mustache
Member Posts: 10 ■□□□□□□□□□
If you don't know already know, subnettingpractice.com (and similar sites) are very useful once you get the basics down.
