Amazon AWS - VPC network/subnet plan

network.txt

VPC   Network (CIDR)    Designation   Region
===   ==============    ===========   ======
1     10.100.0.0/16     Management    Asia Pacific (Tokyo)
2     10.110.0.0/16     Production    Asia Pacific (Tokyo)
3     10.120.0.0/16     Staging       Asia Pacific (Tokyo)

Addressing scheme:

  10.XXX.YYY.0/16
      |   `------ Subnet (e.g. Public and/or Private) 
      `---------- VPC (e.g. Management, Production, etc.)

Note: VPC peering is NOT possible across AWS regions.

Subnet (CIDR)     Designation                Availability Zone
=============     ===========                =================
10.XXX.1.0/24     Public 1 (DMZ)             Asia Pacific (Tokyo) - A -.
10.XXX.2.0/24     Public 2 (DMZ)             Asia Pacific (Tokyo) - B   |- Public network (NAT, bastion, etc.)
10.XXX.3.0/24     Public 2 (DMZ)             Asia Pacific (Tokyo) - C -'
10.XXX.10.0/24    Private 1 (Services)       Asia Pacific (Tokyo) - A -.
10.XXX.20.0/24    Private 2 (Services)       Asia Pacific (Tokyo) - B   |- Web tier (front-end)
10.XXX.30.0/24    Private 3 (Services)       Asia Pacific (Tokyo) - C _'
10.XXX.110.0/24   Private 4 (Persistence)    Asia Pacific (Tokyo) - A -.
10.XXX.120.0/24   Private 5 (Persistence)    Asia Pacific (Tokyo) - B   |- Database tier (back-end)
10.XXX.130.0/24   Private 6 (Persistence)    Asia Pacific (Tokyo) - C _'

Note: The subnet 10.XXX.0.0/24 was left alone as Amazon reserves first
      five (5) addresses for an internal use.

Address allocation:

  10.XXX.YYY.0/24
   `- 10.XXX.YYY.1  - 10.XXX.YYY.10 (Reserved - Internal Use Only)
   `- 10.XXX.YYY.11 - 10.XXX.YYY.254

Note: First ten usable IP addresses of each subnet are reserved for internal use
      only e.g. NAT instances, internal and/or external ELBs, utility servers, etc.

Alternatively, this can be done using 172.16.0.0/12 range split into /16 which is then
split into corresponding /24 e.g.

* 172.16.0.0/16
   |
   +- 172.16.0.0/24
   +- 172.16.1.0/24
   `- 172.16.2.0/24
* 172.17.0.0/16
* 172.18.0.0/16
* 172.19.0.0/16

Cross region VPC peering is now available 🐼