Stage 1 · Lesson 5 of 8
VLSM and address plans
(VLSM) means giving each network a subnet of the right size instead of the same size everywhere. You start with the largest requirement, allocate it at the start of the block, then work down through smaller ones, so nothing overlaps and the leftover space stays in one piece.
A branch office might need a /25 for staff, a /26 for guests, a /28 for printers, /30 or /31 links between and /32 loopbacks. Good plans also leave room to grow and keep related subnets together so they can be summarised as one route later. Write your plan in a table with the subnet, purpose, gateway and .
Common trapallocating small subnets first and ending up with gaps too small for the next large network.
A question to check yourself, an AI practice session and 2 cheat sheet entries come with the full roadmap. Unlock
Resources for this stage
Start with· follow one of these
- PlatformFreeCisco Networking Academy
Cisco · Beginner
Start with the free, self-paced Networking Basics course; it uses Packet Tracer from the first modules
- VideoFreeComputer Networking: A Top-Down Approach (Video Lectures)
Jim Kurose and Keith Ross · Intermediate
Free university-level lectures from the authors of the classic textbook, for the why behind every layer
Practise
Keep handy
Also worth your time
A clear comparison of the two transport protocols and when each one fits
- Beej's Guide to Network ProgrammingGo deeper
If you code, write a tiny TCP and UDP client and server to see the transport layer from the inside