Bandwidth Costs and Time
The information presented is somewhat dated, but fascinating none the less. -Editor
Does transferring a terabyte of data via sneakernet make sense? First, consider the bandwidth capabilities and monthly cost of a few common Internet connections.
Cost Download rate Upload rate
(month) per second per second
56.6 Modem $15 5 KB 4 KB
DSL $30 192 KB 24 KB
DSL,Premium $50 384 KB 48 KB
Cable $50 300 KB 30 KB
Cable,Premium $80 600 KB 60 KB
T1 $300 192 KB 192 KB
T3 $1,400 5.4 MB 5.4 MB
OC-3 $7,500 19 MB 19 MB
Of course, costs may vary; I chose costs that jibed with my personal experience and lined up with a few cursory searches for pricing around the web. Please let me know you think these costs are way out of line. Assuming for the sake of argument that these are representative costs and throughput rates, how much would it cost to transfer, let's say, a 20 gigabyte HD-DVD file?
Download 20 GB Upload 20 GB
56.6 Modem 49 days $24.27 61 days $30.34
DSL 1? days $1.26 10 days $10.11
DSL,Premium 15 hours $1.05 5 days $8.43
Cable 19 hours $1.35 8 days $13.48
Cable,Premium 10 hours $1.08 4 days $10.79
T1 1? days $12.64 1? days $12.64
T3 1 hour $1.98 1 hour $1.98
OC-3 17 mins $3.05 17 mins $3.05
And how much could we upload or download in total, assuming we had these connections going full-bore, around the clock?
in 24 hours in 1 month
Download Upload Download Upload
56.6 Modem 422 MB 338 MB 12 GB 10 GB
DSL 16 GB 2 GB 475 GB 59 GB
DSL,Premium 32 GB 4 GB 949 GB 119 GB
Cable 25 GB 2 GB 741 GB 74 GB
Cable,Premium 49 GB 5 GB 1.5 TB 148 GB
T1 16 GB 16 GB 475 GB 475 GB
T3 472 GB 472 GB 14 TB 14 TB
OC-3 1.6 TB 1.6 TB 49 TB 49 TB
Let's say we wanted to send a terabyte of data via sneakernet:
* Two 500 GB hard drives weigh about five pounds; we can wrap the drives in bubble wrap and fit them in a standard FedEx box.
* It costs about $60 to send five pounds in a standard FedEx box coast-to-coast in 24 hours.
* The total transit time is 32 hours: 24 hours, plus 8 hours to copy the data on and off the drives.
We just transferred data at the rate of 9.1 megabytes per second. The only internet connection that's capable of our sneakernet throughput level is the OC-3. None of the others are even close, particularly if you consider the highly asymmetric nature of consumer connections, where upload rate is a fraction of the download rate.
And what about the cost? Not including the $300 expense of the two hard drives (which I think is fair, because they're reusable), the total cost per gigabyte breaks down like so:
Cost per GB Cost per GB
56.6 Modem $1.21 $1.52
DSL $0.06 $0.51
DSL,Premium $0.05 $0.42
Cable $0.07 $0.67
Cable,Premium $0.05 $0.54
T1 $0.63 $0.63
T3 $0.10 $0.10
OC-3 $0.15 $0.15
Sneakernet $0.06 $0.06
It wasn't obvious to me, but the sneakernet math clearly works. This is exactly the kind of insight Jim Gray was famous for.
Jim also says the cost of internet bandwidth was roughly a dollar a gigabyte for Microsoft in 2003. Is that still how much internet bandwidth costs today? According to the figures I found, the only connection that expensive today is a modem. And who uses modems any more? It seems implausible that consumer internet bandwidth would be sold cheaper than large blocks of commercial internet bandwidth. Let's take a look.
* Amazon's S3 service charges 20 cents per gigabye to transfer data.
* Robert X Cringely regularly gets charged 20 cents per gigabyte for NerdTV, and guesses that large bandwidth consumers like YouTube can negotiate rates as low as 10 cents per gigabyte.
* Mitch Ratcliffe did a survey of internet providers and found that most charge 85 cents per gigabyte, and he proposes YouTube could negotiate a rate of 45 cents per gigabyte.
I'm not sure who to believe. It's a good sign that most estimates are under the $1.00 per gigabyte rate that Jim quoted in 2003. I'd like to think that the cost of internet bandwidth is getting less expensive over time. High bandwidth costs lead to a de-facto "popularity tax", and that's like a giant wet blanket over content creators. Cheaper bandwidth is a net public good: it leads directly to more content, and higher quality content, for everyone.