What is a Content Distribution Network or CDN?
A content distribution network (CDN) is a network of proxy servers located in different geographical areas with their data centers (data centers).
These networks intend to distribute services remotely to users to provide high access and performance. CDNs Today, a large amount of Internet content includes Web objects (text, graphics, and scripts), downloadable things (audio and video files, software. And documents), applications (e-commerce, portals), live streaming, Stream-based on ultimatum and form social networks.
The term CDN (Content Delivery Network) operates as an umbrella and includes various content distribution services such as video streaming. Software download, web and mobile content acceleration, licensed / third-party CDNs, transparent caching, services for Routine evaluation of CDNs, load balancing, multi-CDN switching, and cloud intelligence computation. CDN vendors can be active in other industries such as security and WAN optimization.
CDNs are a layer in the Internet ecosystem. Content owners, such as media companies and e-commerce vendors, pay CDN operators to deliver content to their target users. CDNs also pay them to host their servers in the data centers of Internet Service Providers (ISPs), mobile operators, and networks.
What is CDN technology?
CDN nodes are often found in multiple locations on multiple vertebrae (the Internet). Its benefits include lowering bandwidth costs, improving page load times, or increasing content availability globally. The number of nodes and servers that make up CDNs varies depending on their architecture. In some of them, this number gets thousands of nodes and tens of thousands of servers on a large number of remote PoP points. Other CDNs form a global network with fewer geographic PoPs.
Content requests are often algorithmically led to (ninety) nodes that are optimally optimized. When the objective is to maximize implementation, locations that are more suitable for delivering content to the user may be selected. This is done by choosing the areas with the least number of hops. Or the fewest network seconds away from the requester. Or have the most affordable server performance (both current performance and performance history).
The Techniques content networking
The Internet is founded on the principle of end-to-end. This principle holds the network core relatively simple and transfers intelligence as far as possible to the network endpoints, i.e., hosts and clients. As a result, the network core will be simplified, optimized, and committed to data packet transmission.
Content Distribution Network Supports the end-to-end transmission network by spreading it across a combination of intelligent applications that use methods to optimize content distribution. The integrated coverage of this work uses techniques such as web caching, server load balancing, on-demand routing, and content services. These methods are briefly introduced:
Web caches store popular content on the most in-demand servers for the requested content. These shared network tools reduce the required bandwidth and server load. And improve response time for content stored in the cache. caching) or based on pre-loaded content already filled by push caching servers.
Server load balancing in one or more ways. Including service-based methods (global load balancing) or hardware-based methods of layer 4-7 switches (also called web switches). Content switches or Multi-layer switches share traffic between several servers or caches. In this case, a virtual IP is assigned to the switch. The traffic that joins the switch is then routed to one of the real servers connected to it. The advantages of this work are load balancing, increasing total power, enhancing scalability, and providing more excellent dependability redistributing the load of a broken server, and providing server health monitoring services.
Content service protocols
Several protocols are created to deliver access to various content services spread across a content network.
The Internet Content Adaptation Protocol (ICAP) was developed in the late 1990s to deliver an open standard for connecting application servers. The Open Pluggable Edge Services Protocol (OPES) provides a newer and more robust solution. Defines OPES services that can stay on the OPES processor or run remotely on a callout server. Edge Side Includes, or ESI, is a small markup language used to link web content and dynamically used at the edge level.
It is very typical for websites to have generated content. This can be the result of changeable content such as catalogs and forums or personalization. This can cause problems with caching systems. To solve this problem, a group of companies invented ESI.
- Peer to Peer CDNs
- Private CDNs
Peer to Peer CDNs
In peer-to-peer (P2P) content distribution networks, clients provide resources and use them at the exact time. This means that, unlike server-client systems, content-driven networks can function better because more users will start accessing that content (especially with protocols like BitTorrent that force users to share)). This feature is one of the significant advantages of using P2P networks because it will lower the cost of preparation and implementation for the original content distributor.
Private CDNs
Content landlords can make their CDNs if they are not satisfied with the choices or costs of commercial CDN services. These kinds of CDNs are called private. A private CDN possesses PoPs that deliver only their owner’s content. These PoPs can be caching servers, reverse proxies, or application delivery controllers. They can be as simple as two simple caching servers or large enough to provide petabytes of content.
The advent of telecommunication CDNs
The rapid increase of traffic due to online video streaming has high capital costs for high-speed internet providers. These fees are due to the need to reply to this direction volume and retain subscribers by providing good internet service.
So To solve this problem, telecommunications service providers (TSPs) have begun to build their content distribution networks to reduce the demand on the backbone of the Internet and reduce the cost of the required infrastructure. Give.
Benefits of Telecommunication CDNs
Telecommunication CDNs have an advantage over traditional CDNs because they own a network that broadcasts video content.
They own the last mile of the network and can deliver content closer to the end-user because it can be implanted deep in their network cache. In addition, This deep caching underestimates the distance that video data travels over the public Internet platform, delivering it faster and more reliably.
Telecommunication CDNs inherently have a lower cost-benefit because conventional CDNs have to lease bandwidth from them. And incorporate operator marginal costs into their cost structure.
In addition, telecom operators have more control over how they use their help by using their content distribution infrastructure. Content management functions performed by CDNs are often performed without any information or with limited information about the network (topology, usage, etc.) of the telecom operators with whom they interact and do business. Hence This poses challenges for telecom operators who have a limited range of action in the face of the result of this operation on their aid utilization.
United CDNs
In June 2011, StreamingMedia.com reported a group of telecommunications service providers (TSPs). They developed an Operator Exchange (OCX) scheme to connect their networks. And compete with large CDNs such as Akamai or Limelight Networks, covering total POPs worldwide. In this way, telecommunications companies build a suitable CDN, a much more attractive recommendation for a content provider. That plans to provide its content to the union’s target audience.
It is conceivable that more CDN unions will be comprised in the near end. So These unions grow with the membership of new telecommunications companies. That adds network infrastructure and Internet subscribers to the league.
Source:https://mediasoft.ir/%d8%b4%d8%a8%da%a9%d9%87-%d8%aa%d9%88%d8%b2%db%8c%d8%b9-%d9%85%d8%ad%d8%aa%d9%88%d8%a7-%db%8c%d8%a7-cdn-%da%86%db%8c%d8%b3%d8%aa%d8%9f/