Netflix’s streaming stack only works if content arrives fast, consistently, and at enormous scale. That is the practical reason Content Delivery Network (CDN) matters. A modern streaming platform does not serve a file once. It sustains millions of long-lived sessions, adapts bitrate in real time, and rides the messy reality of last-mile networks, congestion, peering quirks, and regional infrastructure variation.
For Netflix, the delivery layer is not a generic hosting problem. It is a global distribution problem with tight constraints. Peak viewing hours create sustained, bandwidth-heavy demand. A short stall is visible. A small increase in startup latency shows up immediately in user experience. Systems that look acceptable for static content can break down under video workloads.
Netflix’s solution is its own CDN strategy, Open Connect. Netflix1 describes Open Connect as the global network responsible for delivering Netflix movies and TV shows worldwide, bringing content close to where they’re watching it, served over HTTP/HTTPS. The essential design choice is locality – place caches at the edge of, or inside, ISP networks and exchange points, then operate the delivery network as a first-class part of the streaming platform.
KeyTakeaways
- Understand what a CDN is and why video streaming places fundamentally different demands on delivery infrastructure than typical web content.
- Learn why Netflix chose to build its own CDN instead of relying entirely on third-party providers, and what scale, cost, and control pressures drove that decision.
- Get a clear explanation of how Netflix Open Connect works and how it differs from commercial CDNs.
- See how Netflix’s CDN is structured at a high level, from Open Connect Appliances to control and data planes, and how proactive content placement replaces reactive caching.
- Gain insight into how architectural choices around locality, routing, and resilience improve streaming performance and reliability.
What Is a CDN?
A CDN is a distributed delivery system designed to move content closer to the end users. Instead of every request traversing long-haul links to a central origin, content is cached on edge servers across many locations. Requests are routed to a suitable edge node so content can be served locally, quickly, and reliably.
Core goals of a CDN
At its core, a CDN exists to decouple user experience from the physical distance to an origin system. By spreading delivery across many geographically and topologically diverse nodes, a CDN absorbs demand spikes and network variability that would otherwise surface directly at the origin. This allows large-scale services to deliver content predictably under load.
- Reduce latency: Shorter paths, fewer hops, less round-trip time.
- Improve availability and reliability: Traffic is spread across many nodes, so localized failures are less visible to users.
- Lower backbone and origin loa: Edge caches handle most requests, keeping origin systems from becoming bottlenecks.
How traditional CDNs work
Most commercial CDNs are designed as generalized delivery platforms that serve many customers and content types. Their architecture focuses on broad geographic coverage, shared edge capacity, and automated routing decisions that balance proximity, load, and availability.
- Edge caching: Frequently requested content is stored on edge servers. When a user requests an item, it is served from cache when available. Cache misses fall back to an origin or upstream node.
- Geographic distribution: Providers place points of presence across metro regions and data centers so edge capacity exists near demand.
- Request routing (DNS, Anycast): Traffic steering typically uses DNS-based mapping to pick an edge site. Some CDNs also use Anycast IP addressing, so routing infrastructure steers traffic to nearby nodes. The goal is not always closest by distance, it is best by topology, capacity, and health.
Why video streaming stresses the CDN model
Video streaming places sustained and highly visible load on delivery infrastructure. Unlike typical web traffic, where requests are short and bursty, streaming workloads involve continuous data transfer and tight performance constraints over long-lived sessions.
- Sessions are long-lived and bandwidth intensive, not short bursts.
- Playback is sensitive to jitter, loss, and transient congestion.
- Adaptive bitrate streaming means clients may request many variants of the same content, multiplying cache objects.
- A cache miss can interrupt user experience, not just slow a page load.
Why Netflix Built Its Own CDN?
Netflix’s CDN is called Open Connect. It is not a marketing layer or a simple replacement for a commercial CDN contract, it is a delivery system that Netflix designed and operates as a core part of the streaming platform. The driving objective, stated consistently in Netflix’s Open Connect documentation, is simple, to deliver internet video efficiently by placing content close to where people actually watch it.
That close to the viewer goal matters because streaming video is dominated by sustained bandwidth, peak-hour concurrency, and last-mile variability. If content is served from distant origins or from edge locations that are geographically near but topologically far, the request path can still cross congested transit links, inefficient peering points, or overloaded interconnects. Netflix wanted more direct control over where bytes originate on the network path, so that performance is less dependent on the unpredictability of upstream routing and multi-tenant CDN tradeoffs. Open Connect achieves this by deploying Netflix-controlled caching servers deep in the internet, inside ISP networks and at major internet exchange points, so most playback traffic is served locally rather than repeatedly pulled across long-haul paths.
Limitations of third-party CDNs at Netflix scale
At Netflix scale, standard CDN reliance introduces constraints that become structural. To control the viewing time of such a large global audience at the same time required a strong CDN.
Cost pressure scales with success
Sustained global video delivery is expensive when priced as commodity egress and multi-tenant capacity. Netflix’s briefing paper states that it has invested over US$1B in developing and deploying Open Connect and has deployed over 14,000 appliances across 142 countries (figures reported in 2020). That kind of capital investment signals a long-term strategy to reduce dependency on variable delivery economics.
Control and visibility become first-order needs
When the delivery layer is operated by third parties, fine-grained routing, cache behavior, and failure response are less transparent. Netflix’s delivery performance depends on ISP topologies and regional interconnect, not just cloud regions.
Locality is not guaranteed by generic designs
A commercial CDN can be nearby geography while still being far by network topology. Netflix explicitly designed Open Connect to sit at the edge of, or within, ISP networks.
The Content Distribution Philosophy Behind Netflix
Netflix’s Open Connect Overview highlights a directed caching model and emphasizes proactive content placement. The practical idea is to avoid repeatedly pulling high-demand video across upstream links. Instead, stage content near demand before peak viewing.
Netflix’s own technical writing supports this approach. In distributing content to Open Connect, Netflix explains how it places content on Open Connect servers (OCAs), which reflects a deliberate placement strategy rather than purely reactive caching known as content hastaging.
Source: Medium
Independent measurement research reinforces that Open Connect is not a small edge deployment. The Open Connect Everywhere paper published by SIGCOMM CC2 characterizes Netflix as a content hypergiant and studies its infrastructure footprint, highlighting the role of internet exchange points and regional ecosystem differences in Netflix deployment strategy.
How Open Connect Differs from Commercial CDNs
Open Connect is purpose-built for one workload i.e Netflix streaming. Netflix’s overview materials emphasize that Open Connect is designed around Netflix delivery requirements and ISP partnership models, not generalized caching for arbitrary customers.
The distinction becomes explicit in operational posture
- Single content catalog, heavily optimized placement
- Predictable traffic patterns, strong demand forecasting signals
- Deep ISP integration, because the edge is often inside ISP facilities
Partnership model with ISPs
Netflix’s briefing paper frames Open Connect as a cooperative approach benefiting ISPs, content providers, and consumers, emphasizing that local servers at the edge of or within an ISP network reduce the distance ISPs must fetch traffic and thus reduce costs.
A separate industry analysis by Analysys Mason3 models the impact of Netflix traffic and Open Connect on ISP traffic-dependent costs, treating Open Connect as a structured partnership mechanism rather than a typical CDN procurement model.
Benefits, in practical terms
Netflix’s documents position the outcome as improved performance and efficiency through localization.
For additional specificity, an APNIC4 study states that Netflix Open Connect is Netflix’s purpose-built CDN responsible for serving 100% of our video traffic. That statement matters because it implies Netflix is not treating Open Connect as a partial optimization, it is the primary delivery mechanism for streaming video.
A Brief Comparison between Traditional CDN and Netflix Open Connect CDN
Netflix’s model differs most sharply along four axes.
| Dimension | Traditional CDN norm | Open Connect pattern |
| Cache population | pull-on-demand | proactive, directed placement |
| Economics | variable spend per delivered byte | capital-heavy, lower marginal cost at scale |
| Control plane | vendor-owned routing and cache policy | Netflix-operated placement, health, steering |
| Best fit | mixed workloads, multi-tenant customers | sustained video streaming with predictable demand |
Netflix’s Open Connect materials repeatedly emphasize directed caching and ISP-local deployment as the efficiency mechanism, which contrasts with demand-driven cache fill typical of general CDNs.
Open Connect works best when the workload is read-heavy, globally distributed, and tolerant of immutable segment caching. High-churn dynamic content benefits far less from this architecture.
Operational ownership is the trade. Netflix gets control and locality. Netflix also inherits the responsibility, hardware lifecycle, telemetry, peering coordination, and failure response at internet scale.
Core Components of Netflix Open Connect CDN
At a structural level, Open Connect separates concerns between where content lives, how it is managed, and how it is delivered to clients. The following components work together to keep video delivery predictable under sustained global load.
Open Connect Appliances (OCAs)
OCAs are custom-built caching servers designed specifically for video delivery. They store encoded Netflix content and serve it over standard HTTP-based protocols.
From a hardware perspective, OCAs prioritize storage capacity, network throughput, and reliability over compute-heavy workloads. They do not run application logic or store user data. Their job is to deliver bytes quickly and consistently.
Deployment locations fall into two main categories:
- ISP data centers: Many ISPs host OCAs directly within their networks. This places content one or two hops from end users.
- Internet exchange points (IXPs): OCAs deployed at IXPs serve multiple networks via peering, extending reach where direct ISP deployment is not feasible.
Netflix has publicly stated that it operates tens of thousands of OCAs across more than 100 countries, reflecting the physical scale of its CDN footprint.
Control Plane
The control plane governs where content lives and how traffic is directed.
Netflix uses predictive models to decide which titles should be cached on which OCAs. Popular content is pushed proactively, rather than fetched reactively after a cache miss. This reduces origin load and avoids cold-start penalties during peak demand.
Monitoring and telemetry play a central role. OCAs continuously report health metrics, load, and performance signals back to Netflix’s control systems. Unhealthy nodes are removed from serving pools automatically.
Software-driven orchestration manages content refresh, cache eviction, and capacity balancing. Human intervention is the exception, not the norm.
Data Plane
The data plane is where video delivery happens.
OCAs serve video in chunks, supporting adaptive bitrate streaming protocols. Clients request different quality levels based on real-time network measurements. The CDN must respond quickly and consistently across those transitions.
Cache behavior is straightforward by design.
Cache hits are served locally from OCAs, delivering low latency and stable throughput.
Cache misses are handled by fetching content from Netflix’s origin infrastructure, then storing it for future requests.
Netflix CDN Architecture (High-Level)
Netflix’s CDN architecture is designed around a simple principle- delivery must be predictable under sustained global load. That requirement shapes how content is prepared, distributed, routed, and ultimately streamed to clients. The architecture favors proactive decisions over reactive recovery, and locality over centralized optimization.
Content Ingestion and Encoding
Before any content reaches the CDN, it passes through Netflix’s encoding pipeline. Raw media assets are ingested into Netflix’s production infrastructure, where they are encoded into multiple bitrates, resolutions, and formats. Netflix has published extensively on its encoding strategy, emphasizing per-title encoding and continuous optimization to balance quality and bandwidth efficiency.
Each title is prepared as a collection of segments suitable for HTTP-based streaming. These segments are designed to be cache-friendly- immutable, reusable across sessions, and shared across many viewers. This preparation step is critical. Efficient caching at scale depends on predictable object sizes, stable identifiers, and format consistency.
By the time content enters Open Connect, it is already structured for large-scale replication and delivery. The CDN does not perform encoding. It assumes encoded assets are ready for efficient transport and caching.
Content Distribution Workflow
Netflix uses a push-oriented distribution model. Content is transferred from origin systems to Open Connect Appliances ahead of demand rather than being pulled reactively on first request.
The placement of content largely relies on popularity signals along with regional viewing patterns and release timings. Global releases are preferred and staged broadly. While the regional and niche content is placed selectively. Netflix believes that this way it reduces cache misses during peak viewing periods. This is generally called directed caching at Netflix.
As a result of this direct caching, most playback traffic is served directly from OCAs instead of central origins, and it helps in reducing upstream load during high-demand windows.
Request Routing
Once content is in place, routing determines which cache serves the viewer.
Netflix primarily uses DNS-based request steering. DNS responses direct clients to suitable Open Connect Appliance clusters based on geography, network topology, and server health. Routing is ISP-aware, not purely location-based.
Health signals continuously update routing decisions. Unhealthy or overloaded appliances are removed from service automatically, preventing traffic from being sent across congested or distant paths when local capacity is available.
Playback and Streaming
At playback time, Open Connect’s role becomes purely delivery-focused.
Video is served in segments over HTTP. Clients request segments sequentially and adjust quality dynamically using adaptive bitrate streaming. Player logic evaluates throughput, latency, and buffer state, then selects the appropriate bitrate representation.
Quality decisions remain client-driven. The CDN ensures all bitrate variants are available with low latency and stable throughput. Close proximity of OCAs allows bitrate transitions to occur quickly, contributing to smoother playback under fluctuating network conditions.
How Netflix CDN Achieves Resilience and Scalability
Netflix designs Open Connect under the assumption that failures are normal. Individual servers, links, and even entire sites can and do fail.
Redundancy is built into every layer. Multiple OCAs serve the same region. Content is replicated across appliances. Routing systems can shift traffic away from degraded nodes without client intervention.
Load is balanced across OCAs within a serving region. During demand spikes, such as major content releases or regional viewing events, the system relies on pre-positioned content and excess edge capacity rather than rapid origin fetches.
Graceful degradation is an explicit design goal. If local capacity is constrained, playback quality may reduce before playback stops. This prioritizes continuity over peak quality, a tradeoff Netflix has discussed in the context of user experience optimization.
Performance and User Experience Impact of Open Connect CDN
Netflix does not treat CDN performance as an abstract metric. It measures impact directly through user experience signals.
Published studies and Netflix’s own technical posts associate Open Connect deployment with:
- Reduced startup times due to closer cache proximity
- Lower rebuffering rates during sustained playback
- Higher average delivered bitrate under stable conditions
- More consistent performance across regions and ISPs
Independent measurement work, including longitudinal studies presented at IEEE INFOCOM, has shown improvements in path length, throughput, and connection stability as Open Connect deployments expanded within ISP networks.
These gains are not incidental. They are the product of architectural choices that prioritize locality, predictability, and control.
Explore the Design Principles Behind Netflix’s High-Scale Systems
Netflix handles massive traffic from global audiences, many times traffic spikes and it’s needs string CDN with load balancing capabilities to manga ethe traffic without any latencies. Netflix is a pure video streaming platform and is serve users without any delays. Netflix CDN Open Connect distributes content close to the users.
If you want to learn the design principles behind netflix high scale systems. Then Interview Kickstart’s Netflix System Design masterclass is for you. Learn how Netflix-style pipelines use CDNs, caching, and event handling. The design principles behind Netflix’s high-scale systems and decode how large-scale systems manage millions of users with real-world examples.
Conclusion
Netflix’s CDN strategy illustrates what happens when delivery is treated as a core engineering discipline rather than a procurement decision.
Open Connect combines proactive content placement, ISP-aware routing, and localized delivery to meet the demands of global video streaming. Netflix’s own documentation and independent research consistently show that placing content close to users improves performance, resilience, and cost efficiency.
The broader takeaway is not that every platform should build its own CDN. It is that at sufficient scale, content delivery architecture becomes inseparable from the product itself.
FAQs: What is Netflix CDN, and How Does it Work?
Q1. What
Netflix CDN, called Open Co
Q2. How does Netflix Open Connect im
By c
Q3. Does Netflix use third-party CD
Netflix primarily relies on its own Open Connect CDN ins
Q4. Where are Netflix Open Connect servers located?
Open Connect servers are deployed insid
Q5. How doe
Netflix uses viewing patterns, regional demand
