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Webcast-Catalyst9k
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Why are there 1024 available subnets instead of just 4?

172.128.0.0 /26

 

My material says this network has 1024 total subnets and 62 hosts per subnet.

 

172.128.0.0

172.128.64.0

172.128.128.0

172.128.192.0

 

These are the only "subnets" I see and understand.

 

Where are the other 1020 coming from?

 

 

 

 

 

1 REPLY

172.128.0.0 it's a class B

172.128.0.0 it's a class B address and you are subnetting it from /16 to /26 which means you are using 10 bits from the host address towards subnet, so your total no of subnets = 2 raise to power N ( N is 10 in your care ) so its 1024.

Also the above mentioned subnets that you created in Red are in correct for /26 mask , they should be :

172.128.0.0/26

172.128.0.64/26

172.128.0.128/26

172.128.0.192/26

Each of the above gives you 64 Host and if you continue on the same logic you will get to 1024 subnets. :-)

Manish

More Info :

http://www.cisco.com/c/en/us/support/docs/ip/routing-information-protocol-rip/13788-3.html

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