CDN overlays (and more on MediaMelon)
I was recently briefed by MediaMelon, a just-launched CDN offering a “video overlay network”. The implications of their technology are worth considering, even though I think the company itself is going to have a difficult road to travel. (MediaMelon has two customers thus far, and is angel-funded; it is entering an extremely tough, competitive market. I wish them luck, since their model essentially forces them to compete in the ever-more-cutthroat CDN price war, as their entire value proposition is tied up in lowering delivery costs.)
In brief, when a content provider publishes its video to MediaMelon, MediaMelon divides the video into small chunks, each of which is a separate file that can be delivered via HTTP, and relies upon the video player to re-assemble those chunks. This chunk-based delivery is conceptually identical to Move Networks streamlets. MediaMelon then publishes the content out to its CDN partners (currently Velocix plus an unannounced second partner). MediaMelon’s special sauce is that these chunks are then delivered via multiple sources. This is normally MediaMelon’s P2P network, with a fallback to MediaMelon’s CDN partners. Since the video is in chunks, the source can switch from chunk to chunk. The video player also reports its performance to MediaMelon’s servers, allowing MediaMelon to draw conclusions about how to serve content. As a delivery-focused company, MediaMelon has decided to leave the value-adds to its media platform partners, currently thePlatform.
Whatever the challenges of their business model, though, the overlay model is interesting, and from a broader market perspective, MediaMelon’s technology highlights several things about video player capabilities that should be kept in mind:
- You can carve up your video and let the player re-assemble it.
- You can deliver using multiple sources, including P2P.
- The player knows what kind of performance it’s getting, and can report it.
These three key things make it extremely clear that it is technically feasible to create a “neutral” CDN overlay network, without requiring the cooperation of the CDNs themselves. MediaMelon is halfway there. It just hasn’t put together all the pieces (the technical hurdles are actually nontrivial), and it is designed to work with partner CDNs rather than force them into competition.
Basically, what a (non-AnyCast) CDN like Akamai or Limelight does, is that they’ve got a central engine gathering network performance data, which it uses to choose an individual CDN server, based on what it believes best for you (where “you” is defined by where your nameserver is). That individual CDN server then delivers the content to you.
What an overlay would have is a central engine that gathers performance data directly from the video player, and has a list of sources for a given piece of content (where that list includes multiple CDNs and maybe a P2P network). Based on historical and currently-reported performance data, it would direct the player to the source that delivers acceptable performance for the least cost. Dividing the content into chunks makes this easier, but isn’t strictly necessary. What you’d effectively have is a CDN-of-CDNs, with the overlay needing to own no infrastructure other than the routing processor.
That is the next-generation CDN. If it were vendor-neutral, allowing the customer to choose whomever it wanted to work with, it would usher in an era of truly brutal price competition.