CONTENT DELIVERY NETWORKS Course: Telecom Technologies Prepared By: - Shiv Kumar Pandey MIT School Of Telecom

Content Outline Overview Content Delivery Network Content Delivery Network architecture Content Delivery Management Content Delivery Network Pricing/Billing Media Streaming services via CDN’s Revenue sharing model from CDN Future Of CDN Case Study: AKAMAI

Content Delivery Network Is a collaborative collection of network element spanning the internet . Content are replicated over several mirrored Web Server. Why it is done? To perform transparent and effective delivery of content to the end- user. To over come the inherent limitations of the Internet in terms of QoS. Improving the performance by maximizing the bandwidth, improving the accessibility.

Generation of CDN 1st Generation :- Focused on Static or Dynamic Web Document 2nd Generation :- Focused on Video-on-Demand (VoD), audio and video streaming .

Model of Content Delivery Network It contains 2 parts:- Encoded media Meta data 3 Main entities in CDN systems are:- Content Provider CDN provider End-User 1.Encoded media include static(content that are not change is called static content example:-www.google.com), dynamic and continuous media data( example:- audio, video, document, images and web pages). 2. Metadata is the content description that allows identification, discovery, and management of multimedia data, and facilitates its interpretation. Content can be pre-recorded or retrieved from live sources; it can be persistent or transient data within the system . A content provider or customer is one who delegates the Uniform Resource Locator (URL) name space of the Web objects to be distributed. The origin server of the content provider holds those objects. A CDN provider is a proprietary organization or company that provides infrastructure facilities to content providers in order to deliver content in a timely and reliable manner. End users or clients are the entities who access content from the content provider’s Web site. CDN providers use caching and/or replica servers located in different geographical locations to replicate content. CDN cache servers are also called edge servers or surrogates. The edge servers of a CDN are called Web cluster as a whole. CDNs distribute content to the edge servers in such a way that all of them share the same content and URL. Client requests are redirected to the nearby optimal edge server and it delivers requested content to the end users. Thus, transparency for users is achieved. Additionally, edge servers send accounting information for the delivered content to the accounting system of the CDN for traffic reporting and billing purposes.

Architectural Component of CDN 4 main component:- Original server Distribution System Request Routing System Account System CDN contain 4 main component that are:- 1. The origin server and a set of replica servers that deliver copies of content to the end users. 2. The request-routing component which is responsible for directing client requests to appropriate edge servers and for interacting with the distribution component to keep an up-to-date view of the content stored in the CDN caches. 3. Distribution component which moves content from the origin server to the CDN edge servers and ensures consistency of content in the caches. 4. The accounting component which maintains logs of client accesses and records the usage of the CDN servers. This information is used for traffic reporting.

Request Routing in CDN Environment A request-routing system is responsible for routing client requests to an appropriate surrogate server for the delivery of content. It consists of a collection of network elements to support request-routing for a single CDN. It directs client requests to the replica server ‘closest’ to the client. However, the closest server may not be the best surrogate server for servicing the client request. a request-routing system uses a set of metrics such as network proximity, client perceived latency, distance, and replica server load in an attempt to direct users to the closest surrogate that can best serve the request. The content selection and delivery techniques (i.e. Full-site and partial-site) used by a CDN have a direct impact on the design of its request-routing system. If the full-site approach is used by a CDN, the request-routing system assists to direct the client requests to the surrogate servers as they hold all the outsourced content. On the other hand, if the partial-site approach is used, the request-routing system is designed in such a way that on receiving the client request, the origin server delivers the basic content while surrogate servers deliver the embedded objects.

Content Delivery Network Pricing/Billing Charging to the customer depend upon the content delivered to the end-user by their surrogate servers. It support an account mechanism that collect and track client usage information. The average cost of charging of CDN services is high Important factor which influence in revenue generation are:- Bandwidth cost Variation of traffic distribution Size of content replicated over surrogate servers Number of surrogate server Reliability and Stability of the whole system

Pricing Model Of CDN Pricing Based On Aggregate Usage Charging on Monthly basis that is 50TB/month Percentile – Based Pricing Pricing based on the 95th percentile of traffic CDN periodically samples the bandwidth usage of a subscribing content provider. It then computes the 95th percentile of usage at the end of the month and charges a price per Mbps based on the 95th percentile of usage.

INDIA 3 Network Operators :- Aksh Optifibre Ltd. IOL Netcom (formerly IOL Broadband Ltd. ) Time Broadband Services Group These 3 company have invested in CDN to provide managed video and IPTV services to India’s operators

Akamai Technologies Leader in providing a secure, outsourced e-business infrastructure services and software. Covers 85% of the market. 20,000 servers in nearly 1,000 networks in 71 countries. It handles 20% of total Internet traffic today. Developed a set of breakthrough algorithms for intelligently routing and replicating content over a large network of distributed servers.

CDN Service and Functionalities Storage and Management of content. Distribution of content among edge servers Cache management Delivery of encoded media Backup and disaster recovery solutions Monitoring and Performance

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