OCI not allowing subnet as 10.0.0.0/17 or 10.0.1.0/1 within a virtual network 10.0.0.0/16

Question

I have VCN with address space 10.0.0.0/16 in OCI.

I wanted to create a subnet with CIDR notation as 10.0.0.0/17 and is not allowed.

I tried 10.0.1.0/17 not allowed.

I can start from 10.0.0.0/24 all the way to /30.

But in Azure I can create a subnet of 10.0.O.O/17 or 10.0.1.0/17 within a VPN of 10.0.O.O/16.

Where am I missing in OCI?

A help would be greatly appreciated.

regards

I tried /17/8, /19 etc but failed

Answer 1

When you divide a 10.0.0.0/16 in 2 subnets they will be:

10.0.0.0/17 10.128.0.0/17

Try that IP with that mask in an IP calculator, and you will see that.

OCI is just calculating it properly.