Remember VLSM
Full name: Variable Length Subnet Mask
Memory aid: Vary the Length to Size each network's Mask.
Avoid overlapping subnet allocations and account for reserved addresses.
Study area: Network architecture & switching · Batch 6
Relevant study for: CompTIA Network+ N10-009 · Cisco CCNA 200-301 · CompTIA Security+ SY0-701 · ISC2 CISSP 2024 outline
Practice with exam flashcards →Networking & Connectivity / Knowledge library
VLSM — Variable Length Subnet Mask
Uses different prefix lengths within an addressing plan.
Why learn VLSM — Variable Length Subnet Mask?
Uses different prefix lengths within an addressing plan.
Where it came from
Avoid overlapping subnet allocations and account for reserved addresses.
- Memory aid (a learning cue, not the expansion): Vary the Length to Size each network's Mask.
Build your understanding
Work through these exercises in order. Try the task before opening a reference.
- Without looking, expand VLSM: Variable Length Subnet Mask.
- Recall this memory aid: Vary the Length to Size each network's Mask.
- Explain the practical use: Uses different prefix lengths within an addressing plan.
- Explain this distinction: Avoid overlapping subnet allocations and account for reserved addresses.
- Identify VLSM in a device specification, architecture diagram, or system inventory.
Documentation and sources
- IEEE 802 LAN/MAN standards (www.ieee802.org)
- IETF Internet standards (www.rfc-editor.org)