IP Camera Bandwidth Calculator

IP cameras transmit two simultaneous video streams. The main stream is the full-resolution, full-quality stream used for recording to the NVR. The sub stream is a lower-resolution, lower-bitrate stream (typically CIF 352×288, D1 704×576, or 720p) used for live viewing on multi-split screens where full resolution isn't needed. Most NVR platforms automatically use the sub stream for live grid views and switch to the main stream when a camera is opened full-screen. Sub streams typically consume 10–25% of the main stream's bandwidth.

Always. Camera traffic should be isolated on a dedicated VLAN for three critical reasons: (1) Performance — camera streams generate sustained high-throughput traffic that can saturate shared network segments and degrade office applications; (2) Security — IP cameras are frequently targeted by attackers; VLAN isolation limits blast radius if a camera is compromised; (3) Management — a dedicated camera VLAN allows QoS policies, ACLs, and monitoring rules specific to surveillance traffic. The NVR/storage server should have one NIC on the camera VLAN and a separate NIC on the management/storage VLAN.

A 4K (8MP) IP camera at 25fps typically uses 8–12 Mbps in H.265 and 16–20 Mbps in H.264. In H.265+ (Dahua Smart Codec) with a mostly static scene, this can drop to 3–6 Mbps. At 15fps the figures are roughly 50–60% of those values. A common mistake is planning 4K camera systems on a standard gigabit network without accounting for the fact that 100 × 4K cameras at H.265/15fps already consume 500+ Mbps — leaving little headroom for live viewing, sub streams, and management traffic. For large 4K deployments, 10 Gbps uplinks between access and distribution switches are essential.

Standard IP cameras (1080p–4MP fixed lens) typically need PoE (IEEE 802.3af) — up to 15.4W per port. PTZ cameras and high-resolution cameras with IR illumination often need PoE+ (IEEE 802.3at) — up to 30W per port. High-power PTZ, multi-sensor panoramic, and thermal cameras may need PoE++ (IEEE 802.3bt Type 3) — up to 60W per port. Always check the camera's maximum power consumption on its datasheet, not just the nominal figure. The PoE switch must have total power budget greater than the sum of all connected devices' maximum draw. A 24-port PoE+ switch with 370W budget supports roughly 24 cameras at 15W each.

H.265+ (Dahua Smart Codec, Hikvision H.265 Pro) extends standard H.265 with scene-adaptive encoding. It identifies static background regions and encodes them at very low bitrate, while maintaining full quality on foreground motion. In low-motion scenes (parking lots, empty corridors, perimeter cameras at night), H.265+ can reduce bandwidth by 50–70% vs standard H.265. In busy scenes (crowded entrances, intersections), savings are less dramatic — typically 20–35%. H.265+ requires compatible cameras and NVRs from the same manufacturer ecosystem (not cross-compatible between brands).

A practical limit is 70–75% of theoretical NIC throughput to avoid packet loss under burst conditions. At 75% utilization, a 1 Gbps NIC handles ~750 Mbps. At 1 Mbps per camera (1080p/H.265/15fps), that's approximately 750 cameras. At 2 Mbps per camera (1080p/H.265/25fps), approximately 375 cameras. At 5 Mbps per camera (4K/H.265/15fps), approximately 150 cameras. For DSS Pro deployments with dedicated Storage Servers, Dahua recommends dual 1 Gbps NIC teaming for Storage Servers handling 200+ cameras, and 10 Gbps NICs for high-density 4K deployments. See the DSS Pro Server Sizing Calculator.