Ref: https://learn.cantrill.io/courses/2022818/lectures/45699910
Subnetting - Key Concepts
Diagram: https://github.com/acantril/aws-sa-associate-saac03/blob/main/0400-TECH_FUNDAMENTALS/00_LEARNINGAIDS/TF-NET-IPAddressingAndSubnetting-3.png
- 🔧 Subnetting = breaking a NW into smaller NWs (subnets)
- 💡 Like slicing a cake into smaller pieces
- 💡 Quite complex process, especially in the beginning, but gets easier with practice
- A NW can be represented with its CIDR = NW's base IP (starting IP) + NW prefix
- e.g.
10.16.0.0-10.16.255.255 = 10.16.X.X = 10.16.0.0/16 (CIDR)
- 💡 CIDR stands for Classless Inter-Domain Routing
- Hints/Tips for prefixes
- Prefix indicates how many octets (bytes) are fixed in the NW
- The bigger the prefix number → the smaller the NW
/0 = whole internet (or address space); /8 = Class A NW; /16 = Class B NW; /24 = Class C NW; /32 = single IP address
- Standard subnetting means breaking a NW into two halves:
- 💡 e.g. Single
/16 NW → 2x /17 NWs
- e.g.
10.16.0.0/16 split into 10.16.0.0/17 and 10.16.128.0/17
- One can keep splitting subnets into smaller subnets → 2, 4, 8… pieces
- Odd number splits valid, but unusual (usually app deployments want symmetric NWs)
- 💡 While all examples here were for IPv4, subnetting works exactly the same way with IPv6
Subnetting Process Step by Step
Diagram: https://github.com/acantril/aws-sa-associate-saac03/blob/main/0400-TECH_FUNDAMENTALS/00_LEARNINGAIDS/TF-NET-IPAddressingAndSubnetting-4.png
- 💡 Highly recommend watching video for this whole process, better than writing it here
- 💡 Practice, practice, practice subnetting until you're comfortable with it
