cdn

首先，让我们来看一下传统的Internet网络的基本结构和数据传输情况，如下图所示。 ​ Internet 网络基本结构及数据传输方式 根据传统的网络结构,用户的访问流程基本如下: 1.用户在自己的浏览器中输入要访问的网站的域名 2.浏览器向本地DNS请求对该域名的解析 3.本地DNS将请求发到网站授权的DNS服务器 4.授权DNS将服务器的IP地址作为解析结果送给本地DNS 5.本地DNS将解析结果返还给用户，同时将该解析结果保存在自己的缓存中，直到相应的TTL（生存周期）过期，才再向网站的授权DNS请求解析 6.用户在得到IP地址后，向该地址所指向的网站的服务器进行访问； 上述传统的访问模式存在着如下几个严重影响互联网用户的访问效率和质量的环节: 首先，传统的DNS解析过程在将网站主机域名转换为IP地址时，并不预先判断该服务器是否正常工作；即使该服务器已经宕机不能提供服务了，用户的请求仍将被发往这台服务器，造成服务的中断。 其次，互联网从诞生的第一天起，就缺乏一个专门的中央管理结构，也缺乏统一的产品和技术标准。这一点曾是互联网得以迅速发展的优势。但是，随着互联网的 规模越来越大，这一点造成了众多不同网络结构并存的局面。不同网络间的兼容以及不同网络运营商/ISP之间的传输瓶颈等问题使得数据的流通受到限制。据统 计，现有互联网上的平均传输速率不高于30Kbps。 另外

CDN概况 CDN的全称是Content Delivery Network，即内容分发网络。 CND加速主要是加速静态资源，如网站上面上传的图片、媒体，以及引入的一些Js、css等文件。 CND加速需要依靠各个网络节点，例如100台CDN服务器分布在全国范围，从上海访问，会从最近的节点返回资源，这是核心。 CND服务器通过缓存或者主动抓取主服务器的内容来实现资源储备。 一、什么是 CDN CDN的全称是(Content Delivery Network)，即内容分发网络。其目的是通过在现有的Internet中增加一层新的CACHE(缓存)层，将网站的内容发布到最接近用户的网络”边缘“的节点，使用户可以就近取得所需的内容，提高用户访问网站的响应速度。从技术上全面解决由于网络带宽小、用户访问量大、网点分布不均等原因，提高用户访问网站的响应速度。 简单的说，CDN的工作原理就是将您源站的资源缓存到位于全球各地的CDN节点上，用户请求资源时，就近返回节点上缓存的资源，而不需要每个用户的请求都回您的源站获取，避免网络拥塞、缓解源站压力，保证用户访问资源的速度和体验 CDN节点 CDN对网络的优化作用主要体现在如下几个方面 解决服务器端的“第一公里”问题 缓解甚至消除了不同运营商之间互联的瓶颈造成的影响 减轻了各省的出口带宽压力 缓解了骨干网的压力 优化了网上热点内容的分布 二、CDN工作原理

My gut feeling is that a SPDY-capable browser will treat it as though it were a SPDY response. However, the most I can find is a reassurance that an H2 response will degrade gracefully to HTTP1.1. I'm considering serving assets in an H2 oriented manner (multiple requests, no domain sharding, etc.), but I do need to support some non-H2 browsers (e.g. Android 4.1's browser). Will I be OK if all the clients are at least SPDY compliant? Bonus question: are there any complications involved with mixing protocols? We're on a web framework that doesn't support H2, but I'm considering serving most of

ellou' Players I need to crate custom CDN -like solution for small app purposes and wonder what is the best way to serving files directly with Play, but not placed under the public directory of the application? I need to gain access to FTP-upload folder. Let's say that my app is run from /home/myaccount/playapps/app201 folder and is available at http://somedomain.tld address. I have also a common FTP account with folder pointing to /home/myaccount/ftp_upload . What is the best way to serve file /home/myaccount/ftp_upload/folder_1/sub_2/file.txt as http://somedomain.tld/ftp_upload/folder_1/sub

Is there any way of achieving a similar versioning solution on a CDN ( not Cloudfront, Edgecast in this case) for js and css files as the rather neat one, combining a Rewrite rule and PHP, described in this thread ? I don't know of a way of making that PHP/mod-rewrite combination work on a CDN, change my versions often, and don't want to do the versioning manually. I use a cookieless, entirely separate domain to serve static content, so I have to specify the full url in the function. For convenience I'll set out the code from the other thread here. First, we use the following rewrite rule in

I have a redirect in Apache config like Redirect temp /foo.xml http://www.baz.com/foo.xml I am trying to add an Expire and m-cache headers for a CDN to this 302. This would be trivial in php, but I need to do this in Apache config files. Normally this is done like this: ExpiresActive On ExpiresDefault "access plus 10 minutes" but this only seems to not work for 302 redirects. Any suggestions? Check out the mod_headers module for Apache. Perhaps something like: <Location /foo.xml> Redirect temp /foo.xml http://www.baz.com/foo.xml Header always set ExpiresActive On Header always set

I use quite a lot of Dojo, but to date I've only used it by including from a CDN such as AOL/Google. Are there advantages to hosting a copy of Dojo rather than using it via a CDN? I don't have much need to alter the code base, but I imagine there are other advantages/disadvantages? by hosting your own Dojo env. you are for example able to make a custom build of dojo. So you only need to load one *.js file. That saves traffic used by the xhr requests. -jstr Disadvantage to hosting anything externally is that you don't have control over it. You won't get this with the Google/AOL CDN but you