VLSM (Variable Length Subnet Masking) means giving each subnet only as many addresses as it needs instead of one fixed size for all. A point-to-point link gets a /30 (2 hosts) while a user VLAN gets a /24 (254 hosts), so no address space is wasted.

Why size subnets to VLANs on a camera network?

A camera VLAN sized to the camera count, a management VLAN sized small, and point-to-point links on /30s keeps the addressing tidy, leaves room to grow, and makes firewall rules simpler than one flat network for everything.

VLSM Subnet Designer

Q: How do I subnet with VLSM?

Sort your subnets largest-first, then allocate each from the base network in order: pick the smallest prefix that fits the required hosts plus network and broadcast addresses, assign the next available block, and repeat. Largest-first prevents fragmentation.

Give each subnet exactly the space it needs. Enter a base network and your list of host requirements — get an allocated plan with network address, mask, usable range and broadcast for each, largest-first so nothing fragments.

Base network

Network address

Base prefix

Subnets needed

Name	Hosts

Allocation

—

of base capacity used → —

Subnets are allocated largest-first from the base network.

Subnet	Network	Prefix	Mask	Usable range	Broadcast	Usable

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VLSM in one paragraph

Old-style subnetting cut a network into equal pieces, so a link needing 2 addresses got the same /24 as a floor of 200 users — wasteful and fast to run out. VLSM (Variable Length Subnet Masking) sizes each subnet independently: a /30 for a point-to-point link, a /26 for a small VLAN, a /23 for a big camera estate. The trick to doing it without fragmenting the space is to allocate largest-first — this tool sorts your requirements by size and lays them down in order from the base network, which is exactly the method taught for CCNA and used in real network design.

Frequently asked questions

What is VLSM?

Variable Length Subnet Masking — giving each subnet only as many addresses as it needs instead of one fixed size.

How do I subnet with VLSM?

Largest-first: for each subnet pick the smallest prefix fitting hosts+2, assign the next free block, repeat.

Why VLSM on a camera network?

Right-sized VLANs (cameras, management, links) keep addressing tidy, leave room to grow and simplify firewall rules.

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AMT SYSTEMS LTD. designs VLAN-segmented networks for cameras, access control and VoIP across Toronto & the GTA.

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