شبكة توصيل المحتوى

(إلى اليسار) التوزيع من خادم واحد
(يمين) مخطط CDN للتوزيع

شبكة توصيل المحتوى Content delivery network أوشبكة توزيع المحتوى (CDN) هي شبكة موزعة جغرافياً من خوادم الوكالة ومراكز بياناتها. الهدف هوتوزيع الخدمة فراغياً بالنسبة للمستخدمين النهائيين لتزويدهم بتواجد وأداء عاليين. وتخدم شبكات توصيل المحتوى جزءاً كبيرا من محتوى الإنترنت، حالياً، بما في ذلك أغراض الوب (النصوص والرسم والبرامج)، والأمور القابلة للتنزيل (الملفات الإعلامية وبرامج الحاسوب والوثائق)، والتطبيقات (التجارة الإلكترونية والبوابات)، وإعلام البث الحي على الإنترنت وإعلام البث حسب الطلب على الإنترنت والشبكات الاجتماعية.

CDNs are a layer in the internet ecosystem. Content owners such as media companies and e-commerce vendors pay CDN operators to deliver their content to their end users. In turn, a CDN pays ISPs, carriers, and network operators for hosting its servers in their data centers.

CDN is an umbrella term spanning different types of content delivery services: video streaming, software downloads, web and mobile content acceleration, licensed/managed CDN, transparent caching, and services to measure CDN performance, load balancing, multi-CDN switching and analytics and cloud intelligence. CDN vendors may cross over into other industries like security and WAN optimization.

التكنولوجيا

CDN nodes are usually deployed in multiple locations, often over multiple أعمدة فقرية. Benefits include reducing bandwidth costs, improving page load times, or increasing global availability of content. The number of nodes and servers making up a CDN varies, depending on the architecture, some reaching thousands of nodes with tens of thousands of servers on many remote points of presence (PoPs). Others build a global network and have a small number of geographical PoPs.

Requests for content are typically algorithmically directed to nodes that are optimal in some way. When optimizing for performance, locations that are best for serving content to the user may be chosen. This may be measured by choosing locations that are the fewest hops, the least number of network seconds away from the requesting client, or the highest availability in terms of server performance (both current and historical), so as to optimize delivery across local networks. When optimizing for cost, locations that are least expensive may be chosen instead. In an optimal scenario, these two goals tend to align, as edge servers that are close to the end-user at the edge of the network may have an advantage in performance or cost.

Most CDN providers will provide their services over a varying, defined, set of PoPs, depending on the coverage desired, such as United States, International or Global, Asia-Pacific, etc. These sets of PoPs can be called "edges", "edge nodes" or "edge networks" as they would be the closest edge of CDN assets to the end user.

The CDN's Edge Network grows outward from the origins through further acquisitions (via purchase, peering, or exchange) of co-locations facilities, bandwidth, and servers.

تقنيات تشبيك المحتوى

The Internet was designed according to the end-to-end principle. This principle keeps the core network relatively simple and moves the intelligence as much as possible to the network end-points: the hosts and clients. As a result, the core network is specialized, simplified, and optimized to only forward data packets.

Content Delivery Networks augment the end-to-end transport network by distributing on it a variety of intelligent applications employing techniques designed to optimize content delivery. The resulting tightly integrated overlay uses web caching, server-load balancing, request routing, and content services. These techniques are briefly described below.

مناحي شبكات توصيل المحتوى

بزوغ شبكات توصيل المحتوى التابعة لشركات الاتصالات

The rapid growth of streaming video traffic uses large capital expenditures by broadband providers in order to meet this demand and to retain subscribers by delivering a sufficiently good quality of experience.

To address this, telecommunications service providers (TSPs) have begun to launch their own content delivery networks as a means to lessen the demands on the network backbone and to reduce infrastructure investments.

أبرز مزودي خدمة توصيل المحتوى

المجانية

BootstrapCDN
Cloudflare
JSDelivr
Coral Content Distribution Network (Defunct)
Incapsula

التجارية التقليدية

أكاماي تكنولوجيز
Amazon CloudFront
Aryaka
Azure CDN
CacheFly
CDN.net
CDNetworks
CDN77
CenterServ
ChinaCache
Cloudflare
Cotendo
Distil Networks
EdgeCast Networks
Fastly
HP Cloud Services
Incapsula
Instart Logic
Internap
Inxy.hosting
Inxyhost.com
LeaseWeb
Level ثلاثة Communications
Limelight Networks
MetaCDN
NACEVI
OnApp
OVH
Rackspace Cloud Files
SpaceCDN.com
Speedera Networks
StreamZilla
Wangsu Science & Technology
Webscale
Yottaa

التابعة لشركات الاتصالات

AT&T Inc.
Bharti Airtel
Bell Canada
BT Group
China Telecom
Deutsche Telekom
Hibernia Networks
KT
KPN
Level ثلاثة Communications
Megafon
NTT
Pacnet
PCCW
Qualitynet
SingTel
SK Broadband
Tata Communications
Telecom Argentina
Telecom Italia
Spark New Zealand
Telefonica
Telenor
TeliaSonera
Telin
Telstra
Telus
Turk Telekom
Verizon

التجارية التي تستخدم P2P للتوصيل

BitTorrent, Inc.
Internap
Pando Networks
Rawflow

الشبكات المتعددة

CDN-Tech
Cloakfusion
GlobalDots
MetaCDN

Generally speaking, all Internet service providers can provide a content delivery network.

انظر أيضاً

Application software
Bel Air Circuit
Comparison of streaming media systems
Comparison of video services
Content delivery network interconnection
Content delivery platform
Data center
Digital television
Dynamic site acceleration
Edge computing
Internet radio
Internet television
IPTV
List of music streaming services
List of streaming media systems
Multicast
NetMind
Open Music Model
Over-the-top content
P2PTV
Protection of Broadcasts and Broadcasting Organizations Treaty
Push technology
Software as a service
Streaming media
Webcast
Web syndication
Web television

الهامش

^ Dan Rayburn (2017-02-13). "Latest List Of CDN Vendors Selling To Broadcasters, Carriers and MSOs" (in الإنجليزية). StreamingMediaBlog.com. Retrieved 2017-02-24.
^ "How Content Delivery Networks Work". CDNetworks. Retrieved 22 September 2015.
^ "How content delivery networks (CDNs) work". NCZOnline. Retrieved 22 September 2015.
^ Saltzer, J. H., Reed, D. P., Clark, D. D.: “End-to-End Arguments in System Design,” ACM Transactions on Communications, 2(4), 1984
^ Hofmann, Markus; Leland R. Beaumont (2005). Content Networking: Architecture, Protocols, and Practice. Morgan Kaufmann Publisher. ISBN .
^ "Online Video Sees Tremendous Growth, Spurs some Major Updates". SiliconANGLE.
^ "Overall Telecom CAPEX to Rise in 2011 Due to Video, 3G, LTE Investments". cellular-news.
^ "How CDN and International Servers Networking Facilitate Globalization". The Huffington Post. Delarno Delvix. Retrieved 9 September 2016.
^ https://cdn.net

للاستزادة

Buyya, R.; Pathan, M.; Vakali, A. (2008). . Springer. doi:10.1007/978-3-540-77887-5_1. ISBN .
Hau, T.; Burghardt, D.; Brenner, W. (2011). "Multihoming, Content Delivery Networks, and the Market for Internet Connectivity". Telecommunications Policy. 35 (6): 532–542. doi:10.1016/j.telpol.2011.04.002.
(2007) "Addressing Click Fraud in Content Delivery Systems" (PDF). Infocom, IEEE. doi:10.1109/INFCOM.2007.36.
Nygren., E.; Sitaraman R. K.; Sun, J. (2010). "The Akamai Network: A Platform for High-Performance Internet Applications" (PDF). ACM SIGOPS Operating Systems Review. 44 (3): 2–19. doi:10.1145/1842733.1842736. Retrieved November 19, 2012.
Vakali, A.; Pallis, G. (2003). "Content Delivery Networks: Status and Trends". IEEE Internet Computing. 7 (6): 68–74. doi:10.1109/MIC.2003.1250586.