随着流媒体的发展，CDN必须发展

CDNs have always been a necessity in the world of streaming video. 尽管一些流媒体提供商, 比如Netflix, 苹果, 和亚马逊, have continued to build their own delivery infrastructures, the majority of streaming providers utilize a combination of CDNs to ensure that their content is delivered in the best possible way to viewers. 这并不是说其他供应商, 比如Disney+和Peacock, don't use their own CDNs as part of the delivery mix (or can't afford to build their own). 相反，这是一个战略决策. Netflix deployed its own CDN technologies into carrier networks as streaming began to surge, which gave it the opportunity to fine-tune and tweak them as streaming grew. But providers like Disney+, Peacock, and HBO Max have dropped into a cresting wave. Deploying their own CDN technologies in lieu of those of commercial providers would be a Herculean task—and an awfully expensive one to get enough infrastructure set to handle hockey-stick subscriber and viewer growth.

It’s probably safe to say that without CDN technologies (like reverse proxies and cache hierarchies), 今天的流媒体将会大不相同. The large commercial CDNs have massive networks, 有时在ISP内部很好地扩展, and ensure that popular content is cached much closer to the viewer than it otherwise would be. Without these networks  and those deployed by companies like Netflix, 流规模, 质量, and availability might have been significantly hampered. 当然, the move from Real-Time Messaging Protocol (RTMP) to HTTP helped as well, 通过启用现有的web交付服务器, 而不是专用的媒体服务器, 参与传送流媒体内容.

But streaming is still only a fraction of total video watched, even post-COVID lockdown. What happens when it's the de facto method for delivering video content? Will the existing CDN approaches be enough to handle the next phase of streaming growth?

当然, there are a variety of ways to architect a CDN. Some, like Akamai’s, utilize algorithms to route around internet congestion. Others, like Limelight Networks', use a lease-wavelength private network. And other companies approach content delivery in their own unique way as well: Fastly, 亚马逊, 威瑞森, CenturyLink, StackPath, 等. In addition, we are starting to see combinations of approaches. Look at CenturyLink's recent acquisition of Streamroot, a peer-to-peer CDN. Although peer-to-peer was panned in the last decade because of some insidious software used to seed peers and its difficulty in securing content, it evolved as a critical delivery component for live-streaming traffic.

不过，CDN技术仍在不断发展. 像Eluvio这样的公司, 用它的“内容结构”," are attempting to redefine the process through which content is made available to end users. It's not just about more infrastructure; it's about using infrastructure differently. But it's also not the only way that the CDN is evolving to meet future streaming demands. As the edge continues to grow in importance to streaming, CDNs will naturally make use of resources that continue to extend closer to the end user in the cloud, 雾, 与雾. It won’t just be about cross-connects and peering fabrics in the future of streaming delivery.

它将是巨大的, 平行, distributed delivery that includes not only commodity and containerized systems, but most likely everything from network-attached storage in the home to the devices we have in our hands. 为了满足可扩展性, 弹性, and 质量 expectations viewers have for streaming (Hint: Consumers don’t care if a video is broadcast or streamed, 只是说它完美无瑕, 不受缓冲等质量问题的影响, 并且随时待命), CDNs will have to break out of the traditional cache/parent-cache/origin architectural model to embrace something that provides delivery on a smaller and more efficient scale.

The CDN is the backbone of streaming, the "coaxial" of the internet video experience. What the future of the CDN will be is anyone's guess, but one thing is for certain: Its evolution will be something to watch.