AWS Certified Solutions Architect - Professional 2020

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Where does this 65,024 number come from? Minute 00:23 of “Network Migrations and Cutovers”

That number should be 65,536. All of the AWS documentation have 65,536 plus it makes sense mathematically so where is 65,024 coming from? Curiously 65,024 = 65,536 – 512. Why is 2 ^ 9 subtracted? Hummm….

2 Answers

That would make sense but in the slides they are not doing that for the /28 mask. Should be the 65536 and 16 or 65024 and 11.


Actually I even debate my own answer. 65536 addresses with only 5 reservations if you are using the entire CIDR block would be 65531 useable addresses.

Hi Ccottondc,

This seems to be a typo. Should be /16 would allow you 65534 usable addresses (65,536 minus broadcast and network address). If you happened to create a VPC subnet for that full /16, then you would be left with 65,531 available addresses.

I’ve just pushed an update to the slide.



Thanks, Scott! 🙂

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