Abstract: Compared with CDN, PCDN has the core advantages of lower cost and better quality. This article will introduce the definition, nouns, functions, architecture , scenarios and advantages of PCDN in detail .
Write in front:
CDN is a content distribution acceleration network widely used in the video cloud industry. Recently, PCDN, a new technology based on P2P and CDN to achieve complementation and integration, has become popular in the circle. PCDN is the introduction of P2P technology into the CDN content distribution acceleration network. Through this model, it can reduce costs while ensuring service capabilities. It can be said to be the most ideal platform for realizing video business scenarios.
Alibaba Cloud PCDN (abbreviation for P2P+CDN) is a content distribution network product based on P2P technology. The perfect combination of the two is more suitable for large traffic distribution. PCDN products are complementary to traditional CDNs. The distributed PCDN system with P2P technology as the core can be seamlessly integrated with traditional CDNs and cloud CDNs to form complementary collaborations. Compared with CDNs, the cost of ownership is lower and the quality is better. core advantages.
This article will introduce the definition, nouns, functions, architecture, scenarios and advantages of PCDN in detail.
1. What is PCDN?
P2P content distribution network (English name: P2P CDN, hereinafter referred to as PCDN) is a low-cost and high-quality content distribution network service built on the basis of P2P technology by mining and utilizing the massive fragmented idle resources of the edge network. By integrating the PCDN SDK (hereinafter referred to as SDK) to access the service, you can obtain the same (or slightly higher) distribution quality than CDN, while significantly reducing the distribution cost. It is suitable for business scenarios such as video on demand, live broadcast, and large file download.
The http request processing flow after using PCDN is as follows:
2. Common nouns
You may be a little unfamiliar with professional vocabulary when you first come into contact with PCDN, but friends who know CDN must not be unfamiliar. Here we briefly talk about it.
3. What features does PCDN have?
**First, full support**
提供强大易用的SDK，支持Android / iOS / OTT / Flash等平台下点播、直播、大文件下载业务，接口统一、各终端平台适配简单；
• 支持多种资源格式类型，点播支持mp4 / hls / flv，直播支持hls / flv；
• 提供管理控制台和丰富的OpenAPI接口，用户能够轻松实现快速配置和实时监控；
第二，技术领先
• 拥有全国布建百万量级服务节点（包括500余个骨干节点+百万量级末梢节点）,整合CDN与P2P技术实现多级网络加速；
• 自主研发业内领先的节点调度系统，拥有100+核心技术专利，实现百万量级节点的全局调度，最优路径完成数据传输，就近访问，保证分发服务质量；
• 同时支持用户热点内容的自动发现缓存机制和人工预推机制等多重内容缓存方式；
• 充分发挥P2P技术特点，在并行传输、弱网优化、下载加速等方面优势明显；
第三，体验优质
• 支持主流终端平台、主流内容格式的内容加速分发，均可达到等于（或略高于）CDN的用户体验指标；
• 针对移动端进行多重优化，支持纯内存模式，不必读写TF/ROM，极低系统资源占用，耗电量基本无区别；
第四，系统安全
• 全面融合阿里云CDN的安全防护机制，在防盗链、抵御DDoS攻击、数据安全方面为用户提供强大支持；
• SDK使用加密鉴权机制，阻止非法接入；
• P2P节点缓存使用高强度加密，防止内容被篡改；
四、PCDN的基础架构
关键组件
• index服务：全局调度，把用户请求调度到最佳的机房
• ZooKeeper (Global&Local)：服务活动情况汇报给调度服务，动态配置更新
• Nignx Proxy：支持私有协议的Nginx代理服务，针对不同文件一致性Hash到不同的Channel服务
• Channel服务：记录文件和拥有文件的端点地址信息，为下载提供就近的端点地址
• Realy服务：服务P2P建立连接和通讯
• Hot服务：hot文件发现和推送
PCDN架构图：
五、PCDN都适用哪些场景？
PCDN产品适用于视频点播、直播、大文件下载等业务领域。
• 视频点播：长视频点播，热度集中的短视频点播。
• 视频直播：大型晚会赛事直播、地方网台直播、秀场互动直播。
• 大文件下载：超过1MB且热度集中的的文件分发，如应用市场分发、在线音频分发。
六、PCDN好在哪？
介绍了这么多，最后我们来说说，PCDN作为阿里云普惠科技的又一大招，它到底好在哪里，为什么受到了客户和行业的追捧和重视。
价格低：通过P2P技术可为客户提供更低成本的内容分发服务，（以峰值带宽计价）为云CDN价格的1/2，为传统CDN价格的1/4，可显著降低客户的分发成本；
质量好：通过CDN+P2P多级节点调度，一个请求可由CDN和多个P2P源同时提供内容，通过资源冗余提高了服务可用性，播放流畅率高于纯CDN，在大文件下载场景中更是能极大提高下载速度；通过调用海量分布式P2P节点， 平均播放流畅率 > 97%，平均首播时间小于1秒，用户体验得到有效提升。
Mature and stable: It has provided Youku Tudou with high-quality video playback, download and other acceleration services for many years, with access bandwidth exceeding 10T, and has experienced a long-term verification of massive user scale. It has core technologies and patents in various aspects such as intranet penetration, cache processing, seed management, and transmission strategies.
Write at the end:
As a leading cloud computing manufacturer in China, Alibaba Cloud has always been committed to technology inclusiveness. Different from the industry norm, Alibaba Cloud has not tried to increase bandwidth and profitability. Instead, Alibaba Cloud is using its own technology to help customers effectively reduce fees, focus on business, and increase revenue, thereby promoting the development of the entire Internet industry. (This is also the reason why we choose to fight side by side with Alibaba Cloud. Every Alibaba Cloud junior hopes to change the world with code through continuous efforts.)
Original link: http://click.aliyun.com/m/26399/