{"id":97375,"date":"2020-10-17T20:42:13","date_gmt":"2020-10-17T18:42:13","guid":{"rendered":"https:\/\/prohoster.info\/blog\/administrirovanie\/neispovedimy-puti-kontenta-ili-pro-cdn-zamolvim-slovo"},"modified":"2020-10-17T20:42:13","modified_gmt":"2020-10-17T18:42:13","slug":"neispovedimy-puti-kontenta-ili-pro-cdn-zamolvim-slovo","status":"publish","type":"post","link":"https:\/\/prohoster.info\/en\/blog\/administrirovanie\/neispovedimy-puti-kontenta-ili-pro-cdn-zamolvim-slovo","title":{"rendered":"The ways of content are inscrutable, or let\u2019s mention a word about CDN","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

\"The<\/p>\n

Disclaimer<\/b>:<\/i>
\nThis article does not contain information previously unknown to readers familiar with the concept of CDN; it serves as an overview of the technology.<\/p><\/blockquote>\n

\nThe first web page appeared in 1990 and was mere bytes in size. Since then, content has scaled both in quality and quantity. The development of the IT ecosystem has led to modern web pages being measured in megabytes, and the trend towards increasing network bandwidth only strengthens each year. How can content providers cover larger geographical areas and ensure users everywhere have high-speed access to information? Content Delivery and Distribution Networks, or simply CDN, are designed to tackle these challenges.<\/p>\n

The Internet is increasingly laden with 'heavy' content. Numerous studies show that users do not want to deal with web services that take longer than 4-5 seconds to load. Too slow loading speeds can lead to audience loss, which inevitably results in decreased traffic, conversion, and therefore profit. Content Delivery Networks (CDN), in theory, allow one to eliminate these problems and their consequences. However, in practice, it is often the details and nuances of specific cases that make a difference, and there are plenty of them in this field.
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Where did the idea of distributed networks originate?<\/h3>\n

\nLet's start with a brief excursion into history and definitions. A CDN is a network of server machines located in various places to provide access to internet content, reaching a large number of users. The idea of distributed networks involves having several Points of Presence (PoPs) that are located outside the origin server. This system can process the influx of requests more quickly, increasing response times and data transfer speeds. <\/p>\n

The problem of delivering content to users became acute at the peak of internet development, that is, in the mid-90s. The servers of that time, whose performance was even below that of modern flagship laptops, struggled to cope with the load and could not handle the ever-increasing traffic. Microsoft spent hundreds of millions of dollars annually on research related to the information backbone (the famous 640 KB from Bill Gates comes to mind). To address these issues, hierarchical caching was employed, moving from modems to fiber optics, and in-depth network topology analysis was conducted. The situation resembled an old locomotive racing down the tracks, being modernized by all possible means to increase its speed along the way. <\/p>\n

By the late 90s, web portal owners realized that to reduce load and meet required requests, intermediary servers needed to be used. This led to the emergence of the first CDNs, delivering static content from various servers geographically distributed around the world. Around the same time, a business model for distributed networks also emerged. The largest (at least one of the largest) CDN providers in the world, Akamai, became a pioneer in this field, starting its journey in 1998. A couple of years later, CDNs became mainstream, and revenues from content delivery and distribution reached tens of millions of dollars monthly.<\/p>\n

Today, we encounter CDNs every time we visit a commercial page with high traffic or engage on social media. Services are offered by: Amazon, Cloudflare, Akamai, and numerous other multinational providers. Moreover, large companies strive to use their own CDNs, which brings them a number of advantages in terms of speed and quality of content delivery. If Facebook did not have distributed networks and relied solely on a single server located in the USA, loading profiles for users in Eastern Europe could take significantly longer. <\/p>\n

A few words about CDNs and streaming<\/h3>\n

\nFutureSource Consulting conducted an analysis of the music industry and concluded that in 2023, the number of subscriptions to music streaming services will reach nearly half a billion people. Moreover, more than 90% of the revenue for these services will come from audio streaming. The situation is similar for video, with terms such as let's play, online concert, and online cinema firmly established in the popular lexicon. Companies like Apple, Google, YouTube, and many others have their own streaming services.<\/p>\n

In the early conception, CDNs were mainly used for static content websites. Static content refers to information that does not change based on user actions, time, or other factors; it is not personalized. However, the development of streaming video and audio services has added another common scenario for utilizing distributed networks. Proxy servers, positioned close to the target audience worldwide, provide stable access to content during peak load periods, eliminating the lack of \"bottlenecks\" in the internet.<\/p>\n

How it works<\/h3>\n

\nThe essence of all CDNs is approximately the same: to use intermediaries to deliver content faster to the end consumer. It works as follows: a user sends a request to download a file, which is received by the CDN server, making a one-time request to the original server and delivering the content to the user. Simultaneously, the CDN caches the files for a specified period and processes all subsequent requests from its own cache. Optionally, they can also pre-load files from the source server, set cache expiration times, compress large files, and much more. Ideally, the host transfers the entire traffic stream to the CDN node, which then uses its own resources to deliver content to users. Naturally, effective caching of information, as well as distributing requests across a network instead of a single server, will lead to a more balanced load on the traffic. <\/p>\n

\"The
\nThe second important feature of CDN operation is the reduction of data transmission delays (also known as RTT \u2013 round trip time). The establishment of a TCP connection, loading media content, JS files, and starting a TLS session all depend on ping. Obviously, the closer you are to the source, the faster you can receive a response from it. Even light has its limits: about 200,000 km\/s through fiber optics. This means that the latency from Moscow to Washington will be about 75 ms in RTT, and this is without the influence of intermediate equipment. <\/p>\n

To better understand the tasks solved by content delivery networks, here is a list of current solutions:<\/p>\n