Archive for July, 2009

Definition

Question: What is the definition of a CDN?

Content owners of course compare CDN’s. But what is a CDN? Some say that CDN’s have become a commodity. I disagree. There are so many different approaches. Comparing CDN’s is comparing apples and pears. I have seen some lists on the net that try to categorize CDN’s into different categories. But IMHO that does not help content owners compare CDN’s.

Historically a CDN is a highly decentralized file distribution & geographical user load balancing platform.  The best example is Akamai who has deployed thousands of servers globally, close to many ISP networks.
Some claim that the Akamai model defines what a CDN is. But today there are so many different approaches, with different technologies, different regions and different market approaches.

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2009
07/31
POSTED BY
Stef
CATEGORY
Uncategorized
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Europe calling

This is a call to some USA CDN industry writers who primarily write about global (in their view that is U.S. based) loss leaders while they could also write about winners.

Jet Stream and StreamZilla are perhaps not the best known brands in the USA CDN industry. That is because we mainly focus on Europe. In Europe we are a market leader with our innovative CDN technology (actually there is no competition, we invented this market here.) Our StreamZilla CDN is the only pan-European Streaming Media Provider. We have an innovative market approach (transparency, e-commerce) to overcome the Europe’s market specific culture.

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2009
07/31
POSTED BY
Stef
CATEGORY
Business
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VideoExchange

VideoExchange (VDO-X) is our killer app. It is a suite of cutting edge CDN technologies. It is the modern version of good old logistics.

VDO-X is an industry disruptive technology because now any network owner can design, deploy and operate a competitive Content Delivery Network.

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2009
07/31
POSTED BY
Stef
CATEGORY
Distribution
Logistics
Technology
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Rediraptor

So you have a large number of servers. How do you load balance viewers over those servers?

You could build a giant farm and use hardware load balancers. Or DNS round robin. This is called a farm, not a CDN.
This implies that all servers need to be able to deliver every asset. Lots of storage costs. No bursting optimization. And there is no geo optimization.

You could redirect viewers by using DNS. Most CDN’s use this.
But DNS can be cached by ISP’s. If you dynamically redirect a user, reroute traffic from geo networks to certain servers, and an ISP overrules your TTL, the users can have a black hole for 24 to 48 hours every time you switch. Ouch.

You could redirect viewers by using BGP. Some CDN’s use this.
But BGP routing could very well imply that you can only distribute from your own network, it requires a lot of knowledge, and it could mean that you have to change the entire network setup. Hmm.

When we had to build our own temporary CDN in the mid 90′s,  we used a simple technology:

Application redirection.
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2009
07/31
POSTED BY
Stef
CATEGORY
Technology
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Replicator

So you have a large number of servers and you want assets and live streams to be available on those servers…

You could sync all assets to all servers. Easy.
That takes a lot of time. And expensive storage. It is not dynamic. Why sync unpopular assets to all servers?

You could setup permanent relays for all the live streams. Easy.
That requires a lot of inter-server traffic. It is not dynamic. Why relay unpopular streams to all servers?

You could use caching servers.
We call this PULL. You redirect a user to a cache. If the cache doesn’t have the asset, it will pull it from an origin server, cache it an serve it. The cache flushes the asset after a certain time.
But this means you cannot fully control which assets are allowed to be on which servers for which customers. You cannot manage thresholds per customer. You cannot assign resources per customer. Caching servers don’t cache streams…

So we wrote our own engine called Replicator. Read more

2009
07/31
POSTED BY
Stef
CATEGORY
Technology
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StreamStat

2003. StreamStat is a fully rewritten, highly optimized, commercialized version of the first rudimentary scripts I had for processing our media server log files.

Media server log files are the most detailed, rich and exact resources for analysis of viewing behaviour of streaming content.

If you use multiple servers and multiple services, the challenge is to get the log files from all the servers on a central server, then merge the log files into global log files.

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2009
07/31
POSTED BY
Stef
CATEGORY
Technology
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XL Media Server

2002. Our first commercial product was XL Media Server. This was a commercialized version of the old parallelization trick I used to run multiple streaming services on a single web server.

XL Media Server now supported Darwin Streaming Server, Apache, RealVideo Server and Windows Media Server. It ran on Windows 2003 server.

I added user management, quota management features and standardized URL’s, content paths and log paths, so the server could be integrated in larger server environments.

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2009
07/31
POSTED BY
Stef
CATEGORY
Technology
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Peer2Peer s*cks, here’s why

Peer2Peer (P2P) is sometimes proposed as an alternative for distributed content delivery. Some CDN’s are built upon P2P technology. P2P vendors, researchers and CDN’s claim that P2P lowers costs. It does. For the content owner. But it raises costs for the network owners. Significantly.

Basically the concept of P2P is that every client can redistribute content to other clients. As a content provider you don’t need to buy servers or traffic. Your audience distributes your content ‘for free’. Ingest the content into the network and let it flow. It is also hard to trace where content is hosted and ingested from. That is why P2P is so popular for (illegal) file sharing services.

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2009
07/31
POSTED BY
Stef
CATEGORY
Distribution
Fiber to the Home
ISP's
Logistics
P2P
The Last Mile
Value chain
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