Performance

Content Delivery Networks, or CDNs, are now invisible yet essential infrastructure. They accelerate websites, deliver video, block attacks, and connect billions of users to online services. Their story stretches from the late 1990s, when a few pioneering companies sold premium acceleration to media giants, to today, when free CDN tiers are available to anyone running a blog. This article traces that history, highlighting the technical and commercial shifts that shaped the CDN industry. ...

Multi-CDN is a strategy that uses more than one CDN at the same time. Instead of relying on a single provider, traffic flows through multiple networks and is steered to whichever one works best at that moment. This approach improves reach, resilience, and sometimes cost efficiency. If you are unfamiliar with the basics of CDNs, see the Top 10 Questions About CDNs first. 1. What is a Multi-CDN and how does it differ from a single CDN? A single CDN depends on one provider’s network of points of presence. A Multi-CDN combines the reach of several providers, switching between them based on performance, location, or availability. The result is fewer single points of failure and a smoother experience for global audiences. ...

Content Delivery Networks, or CDNs, keep much of the modern web running smoothly. They are behind faster page loads, fewer outages, and safer browsing experiences. If you have wondered how they work or whether you should use one, here are the ten questions people ask most — with answers in plain language. For more advanced strategies that combine multiple providers, see the Top 10 Questions About Multi-CDN. 1. What is a CDN and how does it work? A CDN is a network of servers in many locations. It stores copies of website content on those servers so they can be delivered from a place closer to the visitor. Instead of every request going back to the main origin server, a CDN routes the visitor to the nearest edge server. The shorter the journey, the faster the response. ...

CDN providers are adopting AI-driven traffic routing to optimize performance, particularly for video streaming and gaming. Machine-learning algorithms reduce egress costs by 20-30% for hyperscalers, improving throughput during traffic spikes. This enhances user experiences by minimizing latency. AI analyzes real-time data to route traffic through optimal PoP locations, bypassing congested paths. This improves TTFB and reduces p99 latency, critical for real-time applications. The cost savings benefit providers and customers alike. The technology is especially impactful for Multi-CDN setups, where AI coordinates traffic across multiple providers. However, implementation requires robust data pipelines, increasing complexity. Adoption is growing among large-scale platforms. ...

CDN providers like Akamai and Edgio are enhancing live streaming capabilities to support low-latency delivery for cloud gaming and AR/VR. These advancements reduce buffering and improve user experiences, critical for interactive media. CDNs are pivotal for large-scale events. Features like adaptive bitrate streaming and real-time analytics optimize delivery from origin to edge. By leveraging HTTP/3 and QUIC, CDNs achieve faster TTFB, lowering p95 latency for dynamic content. This ensures smooth playback under variable network conditions. Multi-CDN setups amplify reliability for live events, distributing traffic across providers. However, ultra-low-latency requirements challenge existing PoP infrastructure. Providers are scaling edge nodes to meet demand. ...

CDN providers are increasingly integrating edge computing to support real-time applications like video streaming and cloud gaming. By processing data closer to users, CDNs reduce latency, critical for delivering seamless experiences. The rise of 5G networks amplifies this trend, enabling faster content delivery. Edge computing shifts workloads from centralized origin servers to distributed PoP locations. This minimizes round-trip times, improving TTFB for dynamic content. For example, gaming platforms benefit from lower p95 latency, ensuring smoother gameplay during traffic spikes. ...

Indian Railways has upgraded its e-ticketing platform with CDN enhancements, achieving a record 31,800 tickets booked per minute on May 22, 2025. This boost improves access for millions of users, reducing latency during peak booking periods. The upgrade underscores CDNs’ role in high-traffic public services. The system leverages CDN caching and AI-driven traffic management to handle surges at PoP locations. Enhanced origin shielding protects against unauthorized access, ensuring stable performance. The 31,800 tickets-per-minute figure reflects a significant capacity increase, critical for user satisfaction. ...

Multi-CDN strategies are gaining momentum as businesses seek to avoid service disruptions seen in past CDN outages. Companies like Amazon and Walmart use multiple providers, such as Akamai, Cloudflare, and Fastly, to ensure redundancy. This approach maintains content availability during provider-specific failures. Multi-CDN setups distribute traffic across several CDNs, reducing reliance on a single PoP or origin. By leveraging BGP routing and real-time failover, these systems minimize downtime. For e-commerce, this translates to consistent user experiences, even under high traffic. ...

Caching is one of the simplest ways to improve delivery. A cache saves a copy of a response so it can be served without a round trip to the origin. The core control surface is the Cache-Control header and the time-to-live (TTL). This guide explains how freshness and validation work, which directives do what, and how to choose sane defaults that fit real sites and APIs. Freshness vs validation A cache serves a response when it is fresh. Freshness comes from an explicit lifetime such as max-age or from an older Expires date. After freshness ends, a cache either revalidates or fetches again. ...

Synopsis This chapter describes the main architecture patterns for multi-CDN and how to choose between them. It explains DNS-based steering, layer 7 proxy or aggregator designs, client-side selection, and hybrid approaches. It focuses on behavior, failure modes, latency impact, and operational complexity. DNS-based steering Authoritative DNS answers with records that point to different CDNs based on geography, network, or other criteria. This pattern has low per-request overhead because the routing decision happens before HTTP, but it reacts on the scale of DNS caching. Time to live and resolver behavior affect how quickly changes take effect. Geo and ASN databases must be maintained. Health-driven routing requires either short TTLs or resolver-aware mechanisms that may not be consistent across networks. DNS steering is simple to deploy and scales well, but it is limited in how fast it can respond to sudden failures and it has coarse visibility into per-request signals. ...

Synopsis This chapter explains how to design and operate traffic steering for multi-CDN. It covers inputs and data quality, common policy types, precedence rules, health and failover, stability controls, cost awareness, and rollout practices. Inputs and data Effective policies need inputs that reflect user experience and provider health. Synthetic measurements provide controlled and repeatable data but can miss last mile conditions. Real user measurements capture actual paths and networks but require sampling, privacy controls, and careful aggregation. Health signals from providers are useful but should not be trusted without verification. Logs and metrics from the service stack provide the ground truth for outcomes. ...