Intelligent Content Delivery Network (CDN) The New Generation of High-Quality Network

Transcription

1 White paper Intelligent Content Delivery Network (CDN) The New Generation of High-Quality Network July 2001 Executive Summary Rich media content like audio and video streaming over the Internet is becoming more and more popular. Most service providers are now looking at and adding these highly profitable new value-added services. However, traditional networks are not ready for rich media since it has high network and server requirement. Each request for rich media makes an individual connection from the application server to the client. The entire network may go down during the peak of a broadcast or content distribution, when thousands request access to the rich content at the same time. Technical limitations in the distribution and management of Internet broadcasting have stalled the market. In order to scale up an Internet rich media delivery infrastructure to global size with excellent quality, service providers specializing in different segments of the content industry must work together to develop a massive-scale content delivery system. SinoCDN believes that a Content Delivery Network (CDN) built with Intelligent Streaming Gateway (ISG), CDN Manager and MediaDNS is the best solution to optimize Internet content delivery. This paper explores the concept of a CDN for broadcasting and delivering rich media, like audio and video over the Internet, based on SinoCDN's ISG-based intelligent content routing CDN solution. This architecture allows service providers and content distributors to intelligently broadcast thousands of channels to millions of users simultaneously or deliver any application with high reliability and scalability. Introduction More and more content providers are providing streaming media content such as news reports, entertainment shows and remote learning etc. on their web nowadays. With the growing widespread of broadband Internet access services, Internet users have higher bandwidth for accessing information from content providers and can get audio or video content with much higher and more acceptable quality. However, Internet is originally designed for point-to-point applications like , file transfer and web browsing etc. Broadcasting streaming media on the Internet makes many individual connections from the streaming media server to the clients. The entire network may 1

2 go down during the peak of a live broadcast, when thousands requests access to the streaming content at the same time. Industry has tried to overcome this problem through several technologies. One typical solution is to use a streaming servers farm by creating a cluster of streaming media server and using some load-balancing policies. This can support and stream media content to a large audience size. However, the actual problem of network scalability is still unsolved. Another strategy that has been employed is IP Multicasting. It enables one copy of digital information to be received by multiple users simultaneously. However, there is no standard inter-domain multicast routing protocol. It is unlikely that IP multicast can be deployed worldwide with full inter-domain cooperation. Bottleneck Bottleneck Streaming Media Server Internet End Users Bottleneck Traditional Internet In order to scale up an Internet broadcasting infrastructure to television-sized audiences with television-like quality, service providers specializing in different segments of the content industry must work together to develop a large-scale broadcasting delivery system. However, none of the approaches listed above provides a feasible solution that will allow independent content delivery service providers, network service providers, or enterprises to build their own Internet broadcasting networks or interconnect their existing networks into world-wide broadcasting networks economically for supporting thousands of channels to millions of viewers with television-like quality. What is a CDN? A feasible solution for providing such a broadcasting platform is Content Delivery Network (CDN). The concept behind such a network model is to push the content to the edge of the networks and deliver the content with massive intelligence and manageability. Since abundant network bandwidth is usually available in the network edge, we can then push the streaming and distribution to the edge of the network rather than leaving it at the backbone. A single streaming connection at the backbone can be routed on the core network with content-aware intelligence and shared to serve all the clients under the same local network or domain on the edge. 2

3 A CDN is an overlay network to the Internet which has been built specifically for the high-performance delivery of common web objects, static data and rich multimedia content. A CDN makes the Internet a trustful delivery network for mission-critical, content-rich CDN services. The functional components of CDN includes 4 parts: 1. Intelligent User Redirect - User redirection services for directing user to the closest or best cache server (also called request routing), 2. Content Distribution - Distribution services for intelligently distributing content to users or cache machines, 3. Intelligent Content Routing - Intelligent content routing for delivering content from sources to destinations at the network core, and 4. Comprehensive Management - Management, accounting and billing system for measuring, logging and billing customers based on usage. Benefits of CDN for SPs, ICPs, Data Centers and Enterprises CDN technology can change the traditional poor Internet scenario by providing a high-performance, cost-effective and scalable solution which enables service providers (SPs), Internet content providers (ICPs), data centers and enterprises to distribute rich content and streaming media reliably throughout the entire network. For service providers and data centers, CDN can help them to reduce the expensive core network/wan connection bandwidth usage while improving the quality of services. Resources saved can be used to serve more users. Having improved the quality of services, they can then attract more people to subscribe to their services and hence greatly increase their revenue. For ICPs, their content can be published and distributed on the Internet efficiently by CDN technology. By pushing the content to the distributed edge servers, their clients can obtain the content with the best response and quality. At the same time, the problem of network and server scalability is solved, making the coverage of audience significantly increase. Moreover, the management component of CDN technology enables ICPs to manage and publish their content by a one-stop user-friendly tool effectively. Enterprises can also use CDN to help them to carry out business activities effectively. More enterprises are now using rich content like video or audio to make announcements and conferencing; offer training courses to executives; promote present and advertise new products, etc. CDN technology can significantly reduce the cost for carrying out the above activities. Information can be delivered within the company offices or outside the Internet to business partners with the minimum resource/cost and highest quality. Hence, it enables the enterprise to enhance the corporate image and increase the profitability. 3

4 There are already a number of caching devices or splitters in the market aiming for distributing content at the last mile and building CDN. However, most of these cache engines or splitters only perform the task of caching on-demand content and splitting live streams, but do not have internal intelligence to deliver content between the servers on the CDN. These cache engines only communicate with the origin servers or pre-defined parent engines to request the content. The streams cannot be efficiently distributed among the devices on the CDN. In order to further enhance the power of CDN, intelligence of delivering content between cache engines must be added to the core. This intelligence allows the edge servers to search for the required content from the nearest sources (application servers) with considerations on server loading, bandwidth availability and streaming quality. This intelligent content routing feature further reduces the loading on origin servers and consumption on core network bandwidth. Such strategy can be achieved by SinoCDN s intelligent content routing engine Intelligent Streaming Gateway (ISG). Moreover, ISG works CDN Manager and MediaDNS, also SinoCDN s products, and third parties cache engines to provide a complete streaming delivery CDN solution. Building the Intelligent CDN with SinoCDN's Products As CDN is an essential element for enhancing the user experience on the Internet, it is important for anyone who wants to provide professional Internet services by deploying a CDN along with their services. SinoCDN is aimed at providing all-round CDN products that fulfills the 3 functional components of CDN: 1. Intelligent User Redirect - MediaDNS 2. Content Distribution and Intelligent Content Routing - Intelligent Streaming Gateway (ISG) 3. Comprehensive Management - CDN Manager 4

5 Complete Intelligent Streaming Solution: ISG-based Content Delivery Network The following diagram shows the complete solution for building a streaming content delivery network by ISGs. The CDN network built by SinoCDN solution mainly consists of five components: media server, CDN management server, core ISGs, MediaDNS and edge ISGs. When a client requests a media content, MediaDNS will intelligently assign the closest or best ISG node to the client. It ensures that the client can be served by an ISG with the best response and availability. If the request stream is a live content and the assigned ISG is already streaming it to other clients or neighboring ISGs, the ISG will intelligently route and deliver the content to the client immediately. Otherwise, the ISG will communicate with the neighboring ISGs for searching the best node (ISG or media server) to get the stream. For on-demand content, the client will be served immediately from the nearest cache engine if the content is already cached on it. Otherwise, the nearest ISG will send requests to neighboring ISGs for searching the content. The content found will be cached on ISGs on the way and then delivered to the edge ISG. The CDN management server (CDNMS) is a server installed with the network and content management tools - CDN Manager. It allows the complete control over the CDN and all ISGs in the network. After the first installation and configuration of the 5

6 management server on the CDN, all ISGs in the CDN can only be managed by this unique CDN Manager. The ISGs will not follow the instructions or request coming from other management servers. This "trust" system ensures that the CDN cannot be accessed or altered by unauthorized entities, thus providing a secure management environment. CDN Manager allows real-time monitoring and network/content management. The information of the on-demand content cached on edge ISGs in advance is exchanged between ISGs and CDN Manager. Moreover, traffic and bandwidth consumption of the whole CDN and ISGs can be viewed on CDN Manager. Centralized logging system is provided in CDN Manager for operators easy analysis and establishment of billing system. Intelligent Streaming Gateway (ISG) SinoCDN's ISG is a broadcasting node that acts as a core content routing server or edge caching appliance of the network for live and on-demand streaming. It is the fundamental building device of ISG-based and is packaged as a software solution for easy deployment. ISGs can communicate with each other by the advanced technology ActiveRoute. This proprietary communication protocol allows ISGs to obtain application layer knowledge about the network and neighbors status for intelligent content routing. ISGs determine the path for searching or delivering media streams based on the real time information of network latency, server/network loading and available bandwidth. The media content is guaranteed to be delivered to the destination via the best route. Along with each ISG, a web-based administration tool is bundled. It is a management software tool for managing, configuring and monitoring individual ISG. It is designed as web-based so the operators can manage the ISG anytime and anywhere. Benefits of ISG - High-quality stream: Achieve high-performance delivery of rich media streams, leading to a dramatic improvement in customer satisfaction - Intelligence: Patented, sophisticated communication algorithms ActiveRoute between ISGs lead to unmatched software intelligence which enables intelligent content routing on CDN - Multi-format support: Support all popular media formats (RealNetworks RealPlayer TM, Microsoft Windows Media Technology TM, Apple QuickTime TM ) - Carrier-class reliability: Support Gigabit Ethernet for transmitting large volume of transmitted data without single point of failure - Bandwidth saving: Cut bandwidth usage by significantly reducing the number of connections and requests to the origin streaming server 6

7 - Monitoring and manageability: Come with a user-friendly web-based management and configuration package - Simple and cost-effective deployment: Offer all streaming performance benefits in one tiny compact package. MediaDNS SinoCDN's MediaDNS is an intelligent request routing system which directs the user to the closest and the best server node for entering the CDN. It can control a bunch of ISGs as an ISG group. Within the ISG group, MediaDNS can determine which ISG to serve the clients according to the true loading situation of ISGs. When any of the ISGs malfunctions, MediaDNS will immediately detect the failure and redirect the request to other healthy ISGs. MediaDNS provides users with both local and global deployment models. With the local deployment model, MediaDNS can load-balance the ISG to ensure best loading combination when services are running. On the other hand, with the global deployment model, the global mode MediaDNS controls and communicates with the local mode MediaDNS that are located all around the WAN. The global mode MediaDNS will determine the best local mode MediaDNS and ask it to serve the clients when requests are coming. This provides the best global proximity detection for world-wide CDN deployment. Benefits of MediaDNS - Best serving node: Select the closest and the best performing node to serve the clients - Intelligence: Selection of service node is based on the true loading situation of the ISGs, not by predefined round-robin rules - Fault tolerance support: Automatically detect and avoid the failure ISG by redirecting the users to healthy ISGs when any of the ISGs malfunctions - Highly scalable: Deploy as local or global mode to form hierarchical deployment model for large-scale world-wide deployment - Best proximity detection: Global deployment determines the best local mode MediaDNS and best serve the client using the ISGs within the same POP CDN Manager SinoCDN's CDN Manager is a suite of network and content management software tool which enables service/content providers to monitor, view, control and manage the CDN network and streaming content. It is a powerful web-based management tool such that the administrator can access it on the Internet by common web browser. It provides a one-stop interface for administrators to completely control all ISGs, 7

8 content and the whole CDN. Using the CDN Manager, broadcast operators can monitor the health status of the network in real-time, reconfigure links, spot traffic problems, monitor utilization, adjust traffic policies, perform content management and so forth. Benefits of CDN Manager - Real-time Monitoring: Real-time monitoring on the CDN status. Comprehensive information including health status of the ISGs, stream traffic within the CDN, user viewing information, etc. allows CDN operators to react immediately according to current CDN status - Real-time Configuration: CDN operators can configure their CDN, change the ISGs configurations, manage the CDN topology and mange the content inside the CDN in real-time. The real-time configuration function allows non-interruptable service while the CDN is being updated - Centralized Management: Centralized interface for CDN operators to perform their tasks at one place conveniently, eliminating the time spent on configuring the machine separately - Comprehensive Reporting: Comprehensive logging system for taking all user statistics on the CDN. Information including stream records flowing in the CDN, and user viewing statistics can be exported to 3 rd party products for convenient analysis 8

9 Summary The Internet is changing from delivering only static content to more multimedia content, like audio and video. However, traditional point-to-point Internet communication is not designed for delivering rich media content. It makes a barrier for delivering high-quality media content on Internet. The problems of network scalability and manageability should be solved to eliminate this barrier. Content Delivery Network (CDN) solution is the answer. It is based on the philosophy of pushing content distribution to the edge of the network. However, most existing CDN solution is lacking of intelligent content routing. SinoCDN s solution solves this problem. The innovative product ISG enhances the Internet with the ability of delivering high quality live and on-demand media with intelligent routing protocol. A lot of the network resources are saved while high quality streams can be provided to end users. CDN Technologies like request routing and management are also provided by CDN Manager and MediaDNS, also SinoCDN s products. SinoCDN s Content Networking Solution guarantees that service providers and enterprises to build an intelligent network for profit-making business. About SinoCDN SinoCDN is the leading broadband infrastructure technology developer in Asia. It offers content networking and management technology, which enables high-quality live and ondemand content delivery over the Internet from long haul to edge networks. Their products are based on their innovative Intelligent Streaming Gateway architecture that can create reliable, intelligent, scalable and easy-to-manage Content Delivery Network infrastructure for millions of users with best viewing experience. The company is headquartered in Hong Kong, with offices in Boston US. Additional information is available at 9