Introduction to CDN application in Linux

It is composed of a global Load balancer F5 and a CacheServer distributed across eight nodes nationwide. It provides page access acceleration and download acceleration. No. Name function machine room 1 F5 Load balancer Beijing Telecommunications 2 CDN-BZ CACHESERVER Shandong Netcom 3 CDN-CS CACHESERVER Jiangsu Telecom 4 CDN-CX CACHESERVER Yunnan Telecom 5 CDN-CZ CACHESERVER Hebei Netcom 6 CDN-HZ CACHESERVER Zhejiang Telecom 7 CDN-NC CACHESERVER Sichuan Telecom 8 CDN-NN CACHESERVER Guangxi Telecom 9 CDN-SY CACHESERVER Liaoning Netcom user access using CDN cache site access process: 1) The user provides the domain name to be accessed to the browser. 2) the browser calls the domain name resolution library to resolve the domain name. Because CDN has adjusted the domain name resolution process, therefore, the DNS function library generally obtains the CNAME record corresponding to the domain name. To obtain the actual IP address, the browser needs to resolve the obtained CNAME domain name again to obtain the actual IP address; in this process, use global Server Load balancer DNS resolution, as shown in figure The IP address corresponding to location information resolution allows the user to access www.2cto.com 3). This resolution obtains the IP address of the CDN cache server. After the browser obtains the actual IP address, send an access request to the Cache Server 4). the Cache Server obtains the actual IP address of the domain name based on the domain name to be accessed provided by the browser through the internal dedicated DNS resolution (generally through host file resolution) of the Cache, the cache server then submits an access request to the actual IP address. 5) after the Cache Server obtains the content from the actual IP address, it first saves the content locally and uses it as the cache, then, return the obtained data to the client to complete the data service process. 6) the client will display the data returned by the cache server and complete the browsing data request process.
You can compare the access path of a website that does not use CDN cache: the process for a user to access a website that does not use CDN cache is as follows: 1). The user provides the domain name to be accessed to the browser. 2) the browser calls the domain name resolution function library to resolve the domain name to obtain the corresponding IP address of the domain name 3), the browser uses the obtained IP address, send a data access request to the Domain Name Service host 4) the browser displays the webpage content based on the data returned by the domain name host.


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