Rusty Russell's Coding Blog | Stealing From Smart People

Jun/15

1

Block size: rate of internet speed growth since 2008?

I’ve been trying not to follow the Great Blocksize Debate raging on reddit.  However, the lack of any concrete numbers has kind of irked me, so let me add one for now.

If we assume bandwidth is the main problem with running nodes, let’s look at average connection growth rates since 2008.  Google lead me to NetMetrics (who seem to charge), and Akamai’s State Of The Internet (who don’t).  So I used the latter, of course:

Akamai’s Average Connection Speed Chart Q4/07 to Q4/14

I tried to pick a range of countries, and here are the results:

Country % Growth Over 7 years Per Annum
Australia 348 19.5%
Brazil 349 19.5%
China 481 25.2%
Philippines 258 14.5%
UK 333 18.8%
US 304 17.2%

 

Countries which had best bandwidth grew about 17% a year, so I think that’s the best model for future growth patterns (China is now where the US was 7 years ago, for example).

If bandwidth is the main centralization concern, you’ll want block growth below 15%. That implies we could jump the cap to 3MB next year, and 15% thereafter. Or if you’re less conservative, 3.5MB next year, and 17% there after.

RSS Feed

9 Comments for Block size: rate of internet speed growth since 2008?

Yanislav Malahov | June 1, 2015 at 3:23 pm

Well done! I made the same suggestion some weeks ago on Reddit. Nice that you actually provide numbers!

Edmund Edgar | June 1, 2015 at 8:22 pm

It’s nice to see people knocking actual numbers around rather than talking in generalities but I doubt the average connection speed is the right measure here. You’ll end up getting the numbers pulled down by more people connecting on their phones or whatever.

If you tried do the same thing with CPUs and track processing power by looking at the devices people are using at any given time, you’d get something well short of Moore’s Law – during peak smartphone adoption the technology may even appear to have gone backwards.

Nielsen gets a figure of 50% growth per year based on a high-end user’s internet connection, which seems like the relevant consideration.
http://www.nngroup.com/articles/law-of-bandwidth/

Author comment by rusty | June 1, 2015 at 8:53 pm

Excellent points!

I’d guess that the truth is somewhere in between (my personal bandwidth growth is approx 40% over the last 30 years, but it’s closer to 20-25% in the last 8). Yet if we want to increase full nodes, we can’t rely on the highest-end users, so some return to norm would be expected.

On the other hand, the actual usage wasn’t anywhere near 1M in 2008, so saying “1MB was fine is 2008” is clearly another lie :)

Edmund Edgar | June 1, 2015 at 9:22 pm

> Yet if we want to increase full nodes, we can’t rely on the highest-end users

That depends what the goal is in increasing full nodes – only a tiny proportion of people who could be running network-accessible nodes do, so you could potentially get a big increase even if the block size was blowing you in the opposite direction – for example, we were discussing incentives here: http://www.reddit.com/r/Bitcoin/comments/37xtok/using_micropayment_channels_to_incentivise_full/

Mike | June 1, 2015 at 11:19 pm

>> over the last 30 years

30 years? You’ve been online since 1985?

Author comment by rusty | June 3, 2015 at 9:52 am

I’m trying to remember my (parents’) first modem. It might have been a few years later, but it was 300 baud (I remember the 1200/75 audio coupler).

Gavin Andresen | June 3, 2015 at 9:41 am

Another good data source:
http://www.cisco.com/c/en/us/solutions/collateral/service-provider/visual-networking-index-vni/VNI_Hyperconnectivity_WP.html

Home bandwidth seems to be doubling every 5 years seems.

But 1MB is way too small to start; the Akamai report says average global broadband speed us 4.5Mbps, which is over 300MB every ten minutes– plenty of room/speed for much bigger blocks.

Cisco report I link to above says:
“On the fixed networks, data caps continue to increase to match subscribers’ growing appetite for video. In the United States, Tier 1 carriers are considering 500 GB as a possible monthly limit by the 2019 time frame, from a variety of offerings today. A large provider in Japan has a 30-GB per day upload cap.”

Author comment by rusty | June 3, 2015 at 9:51 am

Thanks! I saw a statement about network technology “doubling every 4 years” which I now can’t source :(

Re: 1MB. It’s easy to argue that 1MB is too large: bitcoin wouldn’t have survived hitting that in 2008. For better or worse though, that’s where we did start.

Mark Friedenbach | June 3, 2015 at 10:14 am

Rusty, one issue with the Akamai data is that is consumer-to-CDN, which is a much different metric than bandwidth between peers. New blocks are not going to be cached at the local routing integration point.

«

»

Find it!

Theme Design by devolux.org

Tag Cloud