Case Study: Apple CDN – Part 1


Many thanks to Dan Rayburn for the awesome write up on Apple’s CDN. Now it’s our turn to dissect the Apple CDN, compare it to other CDNs, decide what kind of CDN it is, and make a mini-case study out of it. Let’s start with some CDN history. It took Microsoft years to build out its own CDN, even though they are a leader in Cloud as-as-service, yet Azure is nowhere near Akamai or EdgeCast. In fact, Microsoft still uses 3rd party CDNs for content delivery.

Next, AT&T gave CDN a try, investing more money than Apple, yet they ended up handing it off to Akamai, even though they are the largest Telco in the country, and home to the famous Bell Laboratories. Let’s not forget about some of the pure-play CDNs; they eat, sleep and live CDN, with staff’s larger than Apple’s CDN team, yet these pure-play CDNs are struggling to keep up with the innovation driven CDN leaders. Apple is not a leading Telco, Cloud-as-a-service provider, or a pure-play CDN with hundreds of CDN engineers, so it’s way too early give Apple a CDN crown. For all we know, Apple might give it a try, throw in the towel, hand it off to Akamai, and call it a day.

Apple is one of the largest content companies in the world, serving content, applications, and software to untold hundreds of millions of consumers located in hundred + countries in the world. What is their monthly data transfer? 20PB’s (petabytes), 40 PB’s, 100PBs. Whatever it is, it’s massive, so $100M investment in a CDN is not even a bare minimum to get started. Let’s do some math. If Apple commits to 1Tbps/monthly (in aggregate) of High Speed Internet Service (HSIP is Level 3 term for IP Transit) with multiple carriers, like Telus, DT, NTT and AT&T at a cost of $2/Mbps, the monthly cost is $2M.

  • 1Tbps x $2/Mbps = $2M/month or $24M/year or
  • 2Tbps x $2/Mpbs = $4M/month or $48M/year
  • Some carriers might offer rates at $1/Mbps, but not the USA Tier 1 and Tier 2 Carriers which are defined here

Thus, If Apple commits to 2Tbps/month of HSIP, that’s $48M/year of just transit cost. What about the cost for thousands of expensive servers, routers, switches, co-location facilities, and let’s not forget software engineers. Let’s do some more math. A fully featured server packed with SSD drives, 100GB+ of RAM, latest CPU chip/bus technology and so on, is going to cost $5k to $10k per server. Let’s say its $7k/server, below is a rough cost in aggregate:

  • 1,000 servers x $7k = $7M
  • 5,000 servers x $7k = $35M

Conclusion: If Apple buys 2Tbps of IP Transit and 5k servers, that equates to $85M. Is Apple going to need 5k servers? They’ll probably need much more. Thus, a $100M CDN investment is just a starting point, nothing more. We haven’t even discussed all the features, constant technology stack tuning required, and everything else that is needed to operate a next generation full service CDN. continued in the next post.

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