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Streaming Content Delivery Networks - What You Need To Know

January 07, 2016 by George Avgerakis

The most important part of producing a streaming video is what professionals call, “the last mile.” If conception, planning, production and editing are the first 200 miles of your road to success, the “last mile” is how you stream your program to your viewers - live. The more you know about the last mile, the better you can serve your customers and the more popular and profitable your programs will be.

Most streaming video equipment has a method by which you can select the content delivery network or CDN, which will carry your program to audiences worldwide. Typically, you download a “profile” from a CDN and then configure that profile on your system. The profile allows for a running account of your bill and other necessary information that you provide, such as location, resolution and audio “headroom.”

A CDN is a large array of distributed Internet proxy servers located around the world and maintained for the sole purpose of serving content with high quality and instant availability. CDNs are used for all cloud functions including storage, online computing, website delivery and of course, streaming video. The more hardware a CDN uses to store and/or carry your program, the more they will charge for the service.

Although YouTube provides a free, limited capability to stream to viewers, typically, you will rent the services of a CDN to obtain five key qualities: Scalability, Speed, Security, Solvency, and Service - the five “S’s.”


Scalability is the ability to match the density of your program (usually related to the resolution you’ve chosen) to the bandwidth and speed of the network which will carry your program to the audience - and to the size of the audience in terms numbers and time of attendance.

CDNs are application service providers (ASPs) which offer their services on an as needed basis, depending on the time and bandwidth you require. Consider a CDN like a flexible water main with a variable diameter and any number of drinking fountains. Instead of water, you are sending data. Scalability is the ability of the CDN to push just the right amount of data to all the spigots so everybody drinks just the right flow.



Getting a high-resolution video program to play to thousands of viewers at the same time requires fast “frame load times” and large bandwidth. In order to achieve this, CDNs establish nodes (the actual server hardware) in multiple global locations over a variety of backbones. Backbones are the fiber optic and copper lines that interconnect the large, strategically connected computer networks and core routers of the Internet.

Obviously, the more nodes a CDN has near key backbones, the better the service the speed (and service) offered. The number of nodes and servers controlled by a CDN can vary depending geographically on “points of presence” (PoPs) and numerically by the amount of nodes (ranging from hundreds to tens of thousands). PoPs are made up of physical server locations or points where long distance communications lines of one carrier, say AT&T, connect with those of another carrier, say Sprint. If, for instance, you want a high-speed CDN for distribution of your talk show only in the USA, you would look for a CDN with a high density of nodes in the USA. A global PoP map would not be a high priority.

When you engage a CDN, your demand is going to be directed to nodes by way of some computer allocation program that attempts to optimize your performance. You can evaluate your CDN’s capability in this regard by requesting a list of the locations that will be used to serve your audience employing the fewest “hops.” Each time your data packets move through a router, gateway or bridge (the hardware components of data transmission) small increments of time are wasted. You can request a “hop count” or use software that counts the hops to verify what your CDN claims. You may also be able to request specific locations with the fewest hops, the fastest transmission times between these locations and your anticipated audience locations, or the current and past performance in terms of network availability in order to maximize the quality of your transmission on any given CDN. (See “Free Testing” below.)


The security of your program (and that of the entire CDN network on which your program runs) is important because of the constant onslaught of hackers who may wish to interrupt your program, steel your service capability or obtain valuable information about your clients and/or viewers. The most damaging security loss is through a distributed denial of service (DDoS) attacks, where the capacity of your CDN is reduced or halted by illegal activity that saps the capacity of the system.

CDNs need to be constantly monitoring the users of their systems to detect theft of services, immediately segregate those services from the legitimate users, and eradicate the viruses. Such work, though automated, requires 24/7/365 human availability, usually at multiple sites known as Network Operation Centers or NOCs.

While security may end up being the scapegoat of a bad show, security also implies general reliability, that is, the level of trust you can put in any given CDN that, regardless of security considerations, your program will be delivered on time and with the quality you expect. This can be evaluated through the usual online forums and rating services.



Buying CDN services cost money, usually charged on a per-use or flat fee basis. This money is allocated by the CDN for infrastructure costs, personnel, research and development, and profit.

Just as speed and quality were determined by the amount of nodes, PoPs and their locations, so does your cost. Your CDN may be able to offer you locations that vary in price so as to provide the best quality at the best cost. For instance, depending on the geographic scope of your audience, your CDN may offer a set group of PoPs tailored to your needs. These are called “edge networks” and your goal should be to place the edges of your CDN’s PoP sets as close to your end users as possible.

Like good technological management, a CDN must also have good fiscal management to maintain permanence and quality. You may find that long-term subscription fees, sometimes paid in advance, are at risk if poor fiscal management of your CDN is evidenced. A high-cost, big name CDN may prove to be a wiser vendor over a low-cost operator who ties up your money in bankruptcy. Always examine the market strength of your CDN before entering into any long-term agreements.


Simply put, how easy is it use your CDN and to reach a human being when you need one? In writing this article, I had the opportunity to reach out to several CDN’s public/press relations departments. Some did not list a telephone contact for any portion of their business. Others offered 24/7/365 technical support and returned my calls in 24 hours.

Regardless of how good you are at your work, there will be a “mission critical” time when you need to call a CDN human for help. The time to test this level of service response is long before you add their name to your streamer’s pull-down list of vendors.

Various Types of CDNs

Some CDNs are run by the major Internet providers like Microsoft (Microsoft Azure) and Amazon (Amazon CloudFront). These giants deploy surplus resources on their owned proprietary networks to generate profit from idle hardware. The growth of cloud computing, however, has begun to change the business model as CDN operation moves from an adjunct offering to a primary product.

Although CDNs have traditionally been used by all sorts of data wranglers, the recent exponential increase in video streaming has caused the major telecommunications companies to become CDNs in order to exploit their huge capital investments in video media and to retain subscribers. Consequently, telcos like Verizon, AT&T and Sprint offer varying levels of services to streaming broadcasters. Obviously, these firms own their own continental networks with “into the home” accessibility, so certain cost advantages may be realized.

Large CDNs

Competing with the telcos by installing their own PoPs and nodes are large, traditional CDNs like Akamai, which streams video for the Canadian Broadcasting Corporation, AvidMobile and MTV; Level 3, which serves government, healthcare and financial firms as well as the network video distribution of the Fox Network; and Limelight Networks, which caters to the video gaming needs of Nintendo and the business-to-business (B2B) videos needs of large corporate clients.

Video Optimized CDNs

Since video streaming is only a subset of the many kinds of data that are being distributed by CDNs, a sub-market of CDNs has evolved to handle the specific needs of video producers. Most video optimized CDNs are too small to own a global network, and therefore, lease services from third parties like Amazon and Level 3. There is nothing wrong with this arrangement and the experience for you will be transparent.

By focusing on video-specific needs, these CDNs offer some features that are unique to video streaming, such as video social media integration, audience analytics, multi-format transcoding for mobile and tablets, over-the-top (OTT) distribution, monetization (collecting fees to view your videos), and attention to 2K and 4K high definition formats.

One of the best-known video optimized CDN is Ustream, which offers separate product services for what they consider to be the three dominant categories of video streaming: Pro Broadcasting, Corporate Internal Communications (Ustream Align) and lead-generation marketing (Ustream Demand).

Another video optimized CDN, Streamzilla, is gaining share in Europe and may be a good local choice if your audience is on the other side of the Atlantic. In addition to streaming, Streamzilla also offers resellers the kinds of tools they need to generate revenue and create a network presence.

Free Testing

Most CDNs offer a free trial service. Rather than exploit this to earn a short, obscene profit, why not find a .org and offer them a free streaming experience? Break their show into three parts and allocate these parts to three competing CDNs. After the show, ask your viewers to rate the video quality of the three parts. By choosing a .org with similar geographic and resolution needs to your high paying customer, you can execute a test that matches the customer’s anticipated needs and in the process, perhaps win the .org as a client as well!

I hope this article has increased your desire to learn more about CDN. If as the sages say, the longest journey begins with the first step, really getting there depends on the last mile.

Learn more about Live Production and Streaming

More articles by George Avergerakis:

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Akamai, Amazon CloudFront, AT&T, CDN, Content Delivery Networks, Level 3, Limelight Networks', Microsoft Azure, points of presence, Sprint, Streamzilla, UStream, Verizon, YouTube,

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