High-Performance XDP BNG · CGNAT · QoS · Low-Latency Suite

1 · The problem: bufferbloat and head-of-line blocking

When a subscriber saturates their line — a game patch download, a 4K stream, a cloud backup, or simply several devices active at once — packets arrive faster than the line can transmit them. They pile up in the shaper's queue at the BNG. That queue is where the delay is born.

2 · The solution: the three-layer low-latency suite

3 · Before vs after — the experience difference CENTERPIECE

The following comparison is the core story. A household running a large download (a game patch, an OS update, a 4K stream) normally ruins everyone else's experience on the same line. The suite changes that outcome without touching the download speed.

4 · Production evidence — three independent live nodes REAL DATA

These are not simulations or lab benchmarks. Each node below is an independent live production BNG node on real residential traffic. Node identifiers are anonymized; no hostnames, IP addresses, or customer names are included.

5 · What each subscriber type experiences

The following table maps each common traffic type to the concrete subscriber-felt benefit of the suite — and what the alternative looks like on a standard BNG without it.

6 · How the three functions work together — the coordinated stack

7 · Hardware coverage — runs on your existing fleet

The suite runs across all supported NIC types without modification. The XDP program variant is selected automatically at startup; no operator configuration is required beyond the NIC type being present.

8 · What to expect — rollout, behaviour, and honest framing

The suite is designed so you can turn it on without a maintenance window, a hardware order, or a leap of faith. Each component has an observe-first mode that measures and counts without changing any behaviour.

9 · Measure it, manage it — the operator visibility layer

Section 8 describes the "ALWAYS · TELEMETRY" card — per-subscriber queuing latency and ECN mark counts visible via bngxdpctl metrics and bngxdpctl sub show. The four capabilities below are the concrete realisation of that promise: a complete visibility and management layer that turns "we have low latency" into "we measure every subscriber's experience, continuously, and act on it before exhaustion or before a fault occurs."

9.1 · Subscriber Experience Score — bngxdpctl ses

Every subscriber on the node receives a single 0–100 quality score, computed continuously from the data-plane telemetry the suite already collects. Support staff can open a ticket, look up the subscriber's current SES, and immediately answer "this customer scores 58 — here is why" rather than asking the subscriber to run a speed test. The NOC and product team get a real KPI instead of raw counters: not "average queuing latency was 0.8 ms" but "92% of subscribers scored Good or better at peak hour."

The score is latency-centric by design, reflecting what broadband subscribers actually feel. Typical weighting: queuing latency contributes the majority of the score, consistency and spike avoidance contribute a further quarter, and congestion-related loss accounts for the remainder. Crucially, a subscriber running at their contracted plan rate cap does not score worse for it — the score measures experience quality, not utilisation, and a subscriber who is getting exactly what they paid for should not be flagged as a problem.

9.2 · Application-aware QoS — bngxdpctl app

Traffic is classified into named application categories — video-streaming, gaming, conferencing, software-updates, bulk, and others — by destination and port at line rate in the XDP fast path, with no deep packet inspection and no additional hardware. This gives operators three compounding capabilities on the same platform.

9.3 · Capacity-planning telemetry — bngxdpctl capacity

A single command gives the operator a "how full is this node, and what runs out first?" view across every finite resource simultaneously. Rather than waiting for a fault (subscriber map full → new sessions silently fail; CGNAT port-blocks exhausted → NAT allocation fails; CPU saturated → packet loss begins), the operator sees used / headroom / status for each resource and can order capacity before exhaustion occurs.

The output names the single tightest resource on the node — "CGNAT port-blocks at 78% — approaching WARN threshold; all other resources OK" — so the operator knows exactly where to focus. The command is bngxdpctl capacity; run it in a monitoring loop or integrate the structured JSON output into an existing NOC dashboard via bngxdpctl metrics.

9.4 · Live diagnostics on demand — bngxdpctl debug

When troubleshooting a specific subscriber or a node anomaly, an operator can stream the node's debug detail to their console for a bounded window — typically a few minutes — and then it auto-reverts to normal verbosity. No configuration change is required, no central logging is flooded, and no restart is needed. A small but meaningful "operate it safely in production" capability: the detail needed for a diagnosis is available when required and gone when it is not.

10 · Cost effectiveness and monetization

11 · Fleet-scale numbers MEASURED + PROJECTED