How do I calculate CCTV bandwidth requirements?

Multiply per-camera bitrate (Mbps) × camera count, then add substream load for live preview (~1 Mbps per camera). A 16-camera 1080p H.265 install at 15 fps uses about 16 × 2.4 + 16 × 1 = 54 Mbps on the LAN, comfortably inside a 100 Mbps uplink but borderline if you also need 4K viewing.

Do I need a Gigabit switch for IP cameras?

For 4-16 cameras at 2 MP / 1080p / H.265: a 100 Mbps switch is technically enough but a 1 Gbps managed PoE switch is the standard purchase. For 16+ cameras at 4 MP or higher, or any 4K stream count over 8, 1 Gbps becomes mandatory. For 32+ camera installs, use 10 Gbps uplink between the switch and NVR (SFP+ ports). The price delta from 100 Mbps to 1 Gbps is tiny in 2026 — there's no reason to go cheaper.

What's the difference between main stream and substream bandwidth?

Main stream is the high-quality recording (full resolution, target fps, target codec) — what hits the HDD. Substream is a parallel low-resolution copy (typically 720p @ 10–15 fps, ~1 Mbps) used for live preview, mobile apps, and multi-camera grid views. Most NVR clients pull the substream for grid view and switch to main stream only on a single-camera zoom. Always include substream in network sizing.

How much WAN bandwidth do I need for remote CCTV viewing?

For 1 camera mobile/remote view, 1–2 Mbps upload is enough (substream). For 4-camera grid view on mobile, plan 4–6 Mbps upload. For desktop client viewing the full main-stream of 4 cameras simultaneously, you need 8–16 Mbps upload. Always check your ISP's upload speed (not just download) — residential connections often have 10:1 down:up asymmetry.

Does motion-only recording reduce bandwidth?

Motion-only recording reduces STORAGE but not the peak BANDWIDTH the switch must support — the camera still has to transmit at full bitrate during motion events. Size the network for continuous worst-case throughput. Use the calculator's per-camera bitrate × count value, not a duty-cycle estimate.

Should I VLAN-separate camera traffic from corporate LAN?

Yes for any commercial install. Cameras stream continuously and can saturate switch buffers during high-motion events, causing dropped packets on corporate VoIP and SaaS. Put cameras + NVR on a dedicated VLAN with QoS marking. Most managed PoE switches under €500 support VLAN tagging — there's no excuse to skip this in 2026.