2. Whatis CDN?
A content delivery network (CDN) is a system of computers networked together across the
Internet. The computers cooperate transparently to deliver content (especially large media
content) to end users. CDN nodes (cluster of servers in a specific location) are deployed in
multiple locations, often over multiple backbones.
These nodes cooperate with each other to serve requests for content by end users. They also
transparently move content behind the scenes to optimize the delivery process. CDN serves
requests by intelligently choosing the nearest server. It looks for the fastest connectivity
between your computer to a nearest node that has the content you are looking for.
The number of nodes in different countries and the number of redundant backbone
connectivity a CDN has measures its strength. Some of the most popular CDNs are Akamai,
Limelight, EdgeCast. Akamai is used by large companies like Microsoft, Yahoo, AOL.
Why we need CDN?
The number one reason for using a CDN is to improve your user's experience in terms of
speed, and as we know - speed matters!
Ensuring a consistent experience for all your users is important.
A website may be hosted in a particular region, but have the majority of its users coming
from an entirely different region - for example, if your site is hosted in North America,
3. GTmetrix might report fast speeds based on our default test location, but if a good chunk of
your users come from Europe, their speed will not be as fast as you experience it to be.
A global CDN would allow users from a European point of origin to download static content
from a closer source. Instead of spanning the Atlantic ocean to retrieve data, they can connect
to a server in say, London, UK, to get the same data. This reduces latency and provides a
faster loading of your website.
CDNs not only ensure a faster experience to your users, but they also help to prevent site
crashes in the event of traffic surges - CDNs help to distribute bandwidth across multiple
servers, instead of allowing one server to handle all traffic.
Architecture of CDN
Network administrators today require a content delivery network architecture (CDN
architecture) that can address the increasingly complex challenges of an evolving Internet.
In the past, CDN architecture has bee essential technology for IT administrator seeking to
deliver web content with greater speed, availability and performance. By caching content
across geographically distributed servers in multiple locations, CDN architecture has helped
to optimize delivery by filling requests from the closest server to any given user.
CDN architecture today must respond both to pressure from users who want faster access to
content – especially mobile video – and to advances in technology that are making web
content more complex than ever – from streaming media that causes pages to load more
slowly to mobile devices that request incompatible content far from origin servers.
4. To address these challenges and prepare for the next round of advances and web content, IT
administrators need a next generation, future-proof CDN architecture. That's where Akamai
enters the picture.
Akamai's next generation CDN architecture:
Akamai is the leading provider of cloud services that help businesses deliver secure, high-
performing user experiences on any device, anywhere. As the provider of the world's most
highly distributed CDN, Akamai serves as much as 30% of all Internet traffic and delivers
more than two trillion interactions each day. Akamai's CDN Internet solutions enable
enterprises and network administrators to meet the demands of users and subscribers for fast,
reliable and secure access to complex web content.
Akamai's CDN architecture is built on the Akamai Intelligent Platform, a distributed network
of servers and intelligent software that successfully manages the underlying complexities of
online business. From device and format proliferation, to performance and reliability issues,
to application and network security, the Akamai Intelligent Platform solves the challenges in
delivering secure and high-performing user experiences on any device.
Solutions built on Akamai's CDN architecture:
Akamai helps to support and optimize CDN architecture with a broad range of CDN
solutions.
Akamai Media Delivery Solutions help to meet the demand for faster access to content on an
ever-increasing variety of connected devices, providing a CDN architecture and CDN
streaming server that offer unmatched capacity, scale and geographic reach.
Akamai Cloud Security Solutions help to defend CDN architecture, websites and applications
from increasingly sophisticated threats, including DDoS CDN attacks.
5. Figure: Akamai Edage Server
Akamai Network Operator Solutions help to optimize traffic, build new revenue streams and
reduce costs by minimizing the complexity and improving the efficiency of CDN
architecture.
Advantages and Disadvantages of Using a
Content Delivery Network
A growing trend in the Internet community is the usage of a Content Delivery Network
(CDN) to provide data across nodes in the most effective manner possible. For those
considering implementing such a system, there are many advantages to doing so. However,
there are also several disadvantages that must be also be considered prior to implementation.
Advantages
The advantages include:
Decrease server load
Faster content delivery
100 percent availability
Increase in the number of concurrent users
More control of asset delivery
Decrease ServerLoad
6. As a result, the strategic placement can decrease the server load on interconnects, backbones
and public and private peers, which frees up overall capacity and decreases delivery costs.
Essentially, the content is spread out across several servers, as opposed to offloading them
onto one large server.
Faster Content Delivery
Since CDNs place servers as close to a group of users as possible, latency and packet loss are
minimized due to a shorter distance traveled. Theoretically, the closer the content is to the
user, the faster the delivery. Therefore, users will experience less jitter when streaming, fewer
network spikes, and an overall improved streaming quality. Due to the reliability, operators
can deliver high quality content with a high level of service, low network server loads, and
thus, lower costs.
Additionally, many CDN providers offer TCP acceleration technology which boosts
performance, thus improving user experience. Since CDNs decrease latency, the acceleration
working in conjunction with an already high-performing network results in explosive content.
100 Percent Availability
Due to the distribution of assets across many regions, CDNs have automatic server
availability sensing mechanisms with instant user redirection. As a result, CDN websites
experience 100 percent availability, even during massive power outages, hardware issues or
network problems.
Increase in the number of Concurrent Users
Strategically placing the servers in a CDN can result in high network backbone capacity,
which equates to a significant increase in the number of users accessing the network at a
given time. For example, where there is a 100 GB/s network backbone with 2 tb/s capacity,
only 100 GB/s can be delivered. However, with a CDN, 10 servers will be available at 10
strategic locations and can then provide a total capacity of 10 x 100 GB/s.
Control of Asset Delivery
Another beneficial feature of CDN technology is that more control of asset delivery and
network load is awarded. Operators have the ability to deliver real-time load statistics,
optimize capacity per customer, display active regions, indicate which assets are popular, and
report viewing details to their customers. These details are extremely important, since usage
logs are deactivated once the server source has been added to the CDN.
