Detailed explanation of CDN technology: A complete guide from architectural principles to performance optimization<\/a>\u3002<\/p>\n\n\n\n\nActive and Passive Cache Refresh<\/h3>\n\n\n\n
In addition to relying on expiration times, CDN (Content Delivery Network) also provides an active refresh mechanism. When the content on the origin server is updated, operations personnel can use the console or API provided by the CDN service provider to manually remove the cached data for specific URLs or directories from the edge nodes. This forces the client to retrieve the new data from the origin server during the next access. This is an effective way to ensure that the content is always up-to-date, but it should be used with caution, as frequent refreshes can significantly increase the load on the origin server.<\/p>\n\n\n\n
summarize<\/h2>\n\n\n\n
The acceleration provided by CDN is not some kind of magic, but rather a sophisticated technical system that consists of interconnected components. Starting with intelligent DNS resolution, which directs users to the most appropriate server location, to the use of efficient caching strategies at edge servers to handle requests, and then to various optimizations during the content retrieval and delivery process, every step is designed to reduce the \u201clast mile\u201d between the content and the user. A thorough understanding of the entire chain from DNS to caching enables us to better configure and utilize CDN in our practical work. This not only ensures content consistency but also provides users with a fast and stable browsing experience, thereby gaining a crucial competitive advantage in the digital age.<\/p>\n\n\n\n
FAQ Frequently Asked Questions<\/h2>\n\n\n\nWhat types of content does CDN mainly accelerate?<\/h3>\n\n\n\n
CDNs are primarily designed to accelerate the delivery of static content, such as images, CSS style sheets, JavaScript files, fonts, PDF documents, and audio\/video files. This type of content does not change frequently and can be securely cached on edge servers (located near the users\u2019 locations).<\/p>\n\n\n\n
For dynamic content, such as pages generated in real-time based on user identity or responses from API interfaces, the acceleration effects of traditional CDN solutions are limited. However, modern CDN services also offer dynamic acceleration technologies that improve the transmission speed of dynamic content by optimizing transmission paths, compressing data, and reusing connections.<\/p>\n\n\n\n
After using a CDN (Content Delivery Network), how can we ensure that the content displayed to users is always the latest?<\/h3>\n\n\n\n
Ensure that content updates are primarily achieved through proper cache strategy settings and proactive refresh mechanisms. On the origin server, assign appropriate settings for resources with different update frequencies. Cache-Control<\/code> Header (for example) max-age<\/code>For content that needs to be updated immediately, you can use the \u201crefresh cache\u201d feature provided by the CDN service provider to manually clear the cached data for the relevant URLs after the content is published.<\/p>\n\n\n\nIn addition, file versioning can also be utilized. When the content of a file changes, its filename or query parameters can be updated. As a result, users will be directed to a new URL, which will automatically bypass the old cache.<\/p>\n\n\n\n
How does CDN ensure content security?<\/h3>\n\n\n\n
CDNs use various mechanisms to ensure content security. In terms of transmission security, they generally support HTTPS, which encrypts data during transmission. For access control, they offer features such as Referer protection against hotlinking, IP blocklists and allowlists, and Token authentication, all of which help prevent resources from being misused by malicious actors.<\/p>\n\n\n\n
For more advanced security requirements, CDN services often integrate Web Application Firewalls (WAFs) to protect against common network attacks such as DDoS attacks, SQL injections, and cross-site scripting (XSS). These WAFs serve as an additional layer of defense for the origin servers.<\/p>\n\n\n\n
What other optimizations do source servers need to do to work with CDNs?<\/h3>\n\n\n\n
Even with a CDN, source site optimization is still important. First, the cached HTTP headers need to be properly configured, which is the basis for the CDN's caching behavior. Second, maintain the stability and responsiveness of the source site itself, as cache misses and refreshes still need to go back to the source.<\/p>\n\n\n\n
It is recommended to enable Gzip or Brotli compression to reduce the amount of data transferred back to the source. For cacheable resources, consider storing them under a separate domain name or path for easy CDN policy management. At the same time, monitoring the CDN's back-origin traffic and ratio is an important indicator for evaluating the CDN's effectiveness and the load on the source.<\/p>","protected":false},"excerpt":{"rendered":"
This article systematically analyzes the working principles of CDN (Content Delivery Network) acceleration. Starting from the core architecture and DNS (Domain Name System) intelligent scheduling, it explains in detail how requests are directed to the optimal edge nodes. It also delves into cache hits, the origin-pull mechanism, and cache strategies based on HTTP headers, revealing the complete technical pathway by which CDN achieves efficient content distribution and performance optimization.<\/p>","protected":false},"author":7,"featured_media":0,"template":"","meta":{"_acf_changed":false,"footnotes":""},"tags":[385,398,359,361,520],"knowledge_category":[278],"class_list":["post-12375533","knowledge_post","type-knowledge_post","status-publish","hentry","tag-cdn-acceleration","tag-dns-resolution","tag-content-delivery-network","tag-cache-strategy","tag-network-architecture","knowledge_category-cdn"],"acf":{"site_seo_keywords":"CDN\u52a0\u901f\u539f\u7406,DNS\u89e3\u6790,\u7f13\u5b58\u7b56\u7565,\u5185\u5bb9\u5206\u53d1\u7f51\u7edc,\u8fb9\u7f18\u8282\u70b9,\u56de\u6e90\u673a\u5236,\u667a\u80fd\u8c03\u5ea6,HTTP\u7f13\u5b58\u63a7\u5236"},"_links":{"self":[{"href":"https:\/\/www.likacloud.com\/en\/wp-json\/wp\/v2\/knowledge_posts\/12375533","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.likacloud.com\/en\/wp-json\/wp\/v2\/knowledge_posts"}],"about":[{"href":"https:\/\/www.likacloud.com\/en\/wp-json\/wp\/v2\/types\/knowledge_post"}],"author":[{"embeddable":true,"href":"https:\/\/www.likacloud.com\/en\/wp-json\/wp\/v2\/users\/7"}],"version-history":[{"count":0,"href":"https:\/\/www.likacloud.com\/en\/wp-json\/wp\/v2\/knowledge_posts\/12375533\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.likacloud.com\/en\/wp-json\/wp\/v2\/media?parent=12375533"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.likacloud.com\/en\/wp-json\/wp\/v2\/tags?post=12375533"},{"taxonomy":"knowledge_category","embeddable":true,"href":"https:\/\/www.likacloud.com\/en\/wp-json\/wp\/v2\/knowledge_category?post=12375533"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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