Content Delivery Networks

UK CDN Services

As Web content has diversified into video, games, streaming audio, apps and other forms of rich content, users’ demands have also changed. Today’s expectations are for rapid response, superfast downloads and jitter-free video content accessible anytime and anywhere on both fixed and mobile devices.

To cope with this demand many organizations have turned to specialist content delivery (or distribution) networks (CDNs) to support their content and media strategies. A CDN is a large, strategically distributed, network of proxy content servers, known as Points of Presence (PoPs), or edge servers. The key is to cache the most popular content on these PoPs and then locate them as near to users as possible, thereby boosting download speeds and increasing reliability.

Whenever content is requested by a user’s browser the data has to travel across the Internet from the original website through a series of steps, network to network, by a process of hops. CDN technology aims to reduce the number of such hops, and therefore the latency or delay, by keeping content cached on these localised servers.

The largest CDNs aim to encompass the entire world and use PoPs located in large cities and towns in many different countries to ensure the bulk of the delivery work is decentralised to the far edge of the network.

CDN Caching

The key to successful use of CDNs is a well-designed caching process. Fetching rich content over the Internet, especially if it involves a number of hops, can be slow and require many round-trips between browser and originating web server. The ability to cache and reuse previously fetched content is a critical aspect of Web performance. The goal is to design a topology, and a caching strategy, that increases the cache hit ratio, that is the percentage of browser requests the CDN can answer locally without having to make long-winded requests back to the organization’s original web servers. A good CDN will feature intelligent and highly configurable options, known as edge rules, allowing, for example, the setting of Time To Live (TTL) lifespan for content.

The evolving CDN

CDNs are not a new technology, having been around in some form since 1998, but as digital content has become more sophisticated they have evolved to meet new challenges. Simply caching content is no longer sufficient, and increasingly CDNs are becoming what analysts Forrester® Research term ‘digital performance services’.[1] These take account of both the distribution requirements of different types of content and measures of the complexity of individual pages (e.g. the number of scripts involved).[2]

Rendering the typical modern web page now involves requests for a number of different content objects and types (images, CSS, Flash, JavaScript etc.) pulled in ‘on-the-fly’ from a range of websites, databases and third party services (e.g. social media, video sites, analytics, advertising). They also incorporate general Web performance and front-end optimization techniques to help improve render times.

These techniques include routing optimization, anticipatory prefetching, round-trip reduction through intelligent request bundling, and various compression algorithms. Intelligent sequencing is also often used to display content the user is likely to immediately start reading as a priority (often known as ‘above the fold’ material in deference to the old newspaper industry).

Web-based video also presents its own pressures and involves techniques such as adaptive video rates, optimized transcoding, compression and Quality of Service (QoS) adjustments. With the progressive adoption of high definition display devices, and the emerging 4K/UHD standard, Uk CDN services are increasingly likely to incorporate these advanced IP video delivery features.

Modern CDNs also take account of contemporary concerns over security and privacy issues, providing systems that can offer encryption, digital rights management and protection against Distributed Denial-of-Service (DDoS) attacks, scripting injections, DNS hijacking, and other forms of malware.

1 Mark Grannan, Market Overview: CDN Platforms and Digital Performance Services, (Cambridge, MA: Forrester Research, May 2015)

2 Butkiewicz, Michael., Madhyastha, Harsha., and Sekar, Vyas, Understanding website complexity: measurements, metrics, and implications, In Proceedings of the 2011 ACM SIGCOMM conference on Internet measurement conference (IMC ’11), (New York: ACM, 2011), http://doi.acm.org/10.1145/2068816.2068846

Rendering the typical modern web page now involves requests for a number of different content objects and types (images, CSS, Flash, JavaScript etc.) pulled in ‘on-the-fly’ from a range of websites, databases and third party services (e.g. social media, video sites, analytics, advertising). They also incorporate general Web performance and front-end optimization techniques to help improve render times.

These techniques include routing optimization, anticipatory prefetching, round-trip reduction through intelligent request bundling, and various compression algorithms. Intelligent sequencing is also often used to display content the user is likely to immediately start reading as a priority (often known as ‘above the fold’ material in deference to the old newspaper industry).

Web-based video also presents its own pressures and involves techniques such as adaptive video rates, optimized transcoding, compression and Quality of Service (QoS) adjustments. With the progressive adoption of high definition display devices, and the emerging 4K/UHD standard, CDNs are increasingly likely to incorporate these advanced IP video delivery features.

Modern CDNs also take account of contemporary concerns over security and privacy issues, providing systems that can offer encryption, digital rights management and protection against Distributed Denial-of-Service (DDoS) attacks, scripting injections, DNS hijacking, and other forms of malware.

CDNs and the Cloud

It is important to be clear that employing a CDN is not the same as making use of cloud technologies. A CDN exploits a geographically diverse set of servers, located at strategic points, with a focus on delivering content and enhancing Web performance. Its primary goal is content delivery and replication of content at the edges of the network that are nearest to the user. Cloud computing is concerned with hosting applications and data in a scalable manner and is usually delivered through a huge, single, centralized data centre or a small number spread across the continents. It does not feature end-user geographical proximity as a core function. This is not to say that there are not overlaps, and modern CDNs increasingly make use of cloud-based service providers such as Amazon® AWS as an inexpensive and agile way to enhance their networks.

How it Works

activereach UK CDN services – Content Distribution Network

Many organizations are starting to realise that maintaining their own in-house web server and media content delivery capacity is becoming technically implausible and costly, and are turning to CDNs as the long-term solution. An effective content delivery strategy is essential for customer engagement and retention, e-commerce transaction conversion and successful enterprise application delivery. Implementing a CDN strategy, however, is difficult to get right and activereach offers a highly developed roadmap for getting the best out of the transition in even the most complex and demanding situations.

activereach’s highly pervasive and scalable UK CDN solution is centred on a global PoP system of nearly 200,000 servers spread across six continents. We also offer a dynamic content acceleration system that can complement and add value to an existing CDN provision.

We can help design, build, run and maintain any organization’s content-related delivery requirements from video streaming to 24/7 business application provision. We can improve enterprise application delivery through global distribution, load balancing, performance optimization, traffic offload and secure payload delivery.

It is particularly important for a successful CDN implementation that there is deep knowledge of caching control and its role in the intermediary PoPs across the delivery network. Balancing the needs of users and configuring caching is especially difficult and system administrators often struggle with the configuration of caching control rules. Our systems incorporate advanced configuration technology to ensure that this does not become a roadblock to successful media delivery.

With activereach an organization can increase media delivery scale, availability and capacity; lower costs; exceed user expectations; raise security levels and cope with sudden flash loads. With our solutions, average Web application performance can be enhanced by 25%-30%.

Features

The activereach UK CDN services solution features:

  • Global PoP network with ISP co-location for maximum user proximity.
  • Adaptive content delivery for multiple devices and mobile network access.
  • Video streaming services with adaptive delivery.
  • Dynamic Site Acceleration (DSA) with prefetch, dynamic cache control, compression.
  • Calibrated caching control and configuration.
  • Optimised prefetch and non-cacheable content routing provision.
  • FastTCP congestion-avoidance algorithms.
  • Advanced Web performance optimization and FEO.
  • Token authentication to protect content.
  • In-built security features and protection against DDos attacks.
  • Standards compliant, including the Payment Card Industry Data Security
  • Standard (PCI DSS) and ISO 27001.
  • IPv6, SPDY, HTTPS and HTTP 2.0 support.
  • Real-time Web and user monitoring with caching dashboard.
  • Searchable logs and powerful analytics tools.
  • Rapid design and deployment.

To find out more about CDN solutions from activereach, please call a Networking & Security Specialist on 0845 625 9025.