There have been a few proposals to increase the maximum blocksize in Bitcoin over the past year, but the two plans that are garnering the most attention right now are Jeff Garzik’s BIP 100 and Gavin Andresen’s BIP 101. While Andresen has already implemented his plan in BitcoinXT, Garzik is still working on a formal write-up and the code for BIP 100.

Andresen shared his thoughts on BIP 100 via an interview on Epicenter Bitcoin. Although he did not seem completely dismissive of the proposal, it’s clear that he would prefer to go with his own idea for increasing the blocksize, which would offer more predictability in regard to where the blocksize limit will be in the future.

How BIP 100 Works

When asked directly about BIP 100 by Epicenter Bitcoin co-host Sébastien Couture, Andresen was quick to describe the basic way in which the concept is intended to work:

“Jeff [Garzik]’s proposal is that basically the miners get to decide what the next maximum blocksize should be. There’s kind of a regular vote every — on the order of months.”

Andresen then discussed both BIP 100 and BIP 101 in terms of which proposal would lead to a larger increase in the blocksize limit. The Bitcoin Foundation chief scientist noted that Garzik’s proposal does not come with an immediate increase after it has been implemented, but this does not necessarily mean that it would limit the size of blocks over the short term:

[Garzik] starts with the status quo, so he has no jump-up until the first miner vote. It’s more cautious there. I mean, theoretically, miners could double-up — he has a maximum of 32 megabyte blocks — more quickly. So, if miners wanted to and they all voted for the maximum increase every time, we could be at 32 megabytes more quickly than BIP 101, which would probably be OK if the miners are comfortable with that and they think the network can support it, then OK, so be it.”

Is BIP 100 More Conservative?

Due to the unpredictable nature of Garzik’s BIP 100 proposal, it is difficult to tell if the plan would be more or less conservative than Andresen’s BIP 101. Andresen stated:

Depending on how you look at it, it’s either less conservative or more conservative. It’s probably more conservative.”

If BIP 100 were implemented, it would take a vote from the miners to increase the blocksize limit. In other words, BIP 100 does not increase the blocksize limit by default. It’s also possible that miners could limit the blocksize to a size much smaller than Andresen’s proposed immediate increase to 8 megabytes, which is why some individuals see this proposal as a more conservative approach. On the other hand, miners could vote to increase the maximum blocksize to 32MB in a relatively short period. It is difficult to know which approach would be more conservative without seeing how miners would react to a real-world BIP 100 implementation.

BIP 101 is More Predictable

The key attribute that Andresen likes about his own plan when compared to BIP 100 is that his comes with a predictable increase in the blocksize limit. He explained the importance of this predictability during his Epicenter Bitcoin interview:

I don’t like it as much as BIP 101. I don’t really care what the rule is, but I really like predictable rules. I really like rules that are — I know exactly what the maximum blocksize is going to be on, you know, February 15th, 2022. With BIP 101, we know that. It’s set down there in the spec. We know exactly what it’s going to be, in much the same way that we know what the supply of bitcoin is going to be on that date too — pretty much. [Bitcoin founder] Satoshi [Nakamoto]’s very predictable money supply algorithm for introducing new bitcoins is kind of what inspires me to propose that we just have this limit be very predictable so people can plan… You can do some modeling of what I think the demand for transactions is going to be. You might be able to figure out what the fees are likely to be. All those kinds of things are easier to do if you, kind of, fix this rule as opposed to letting it be miner consensus over time.”

The majority of the network hashrate is currently supporting Garzik’s BIP 100 solution via a Coinbase blocksize vote on the network. Having said that, miners are not the only Bitcoin users with a say in the matter. Many bitcoin exchanges, wallet providers, and payment processors, such as Circle and Blockchain.info, see value in Andresen’s BIP 101 — but not necessarily the BitcoinXT fork. Coming to consensus on this matter has proven to be next to impossible up to this point, but it’s possible that we could be approaching a breaking point with all of the recent activity in the debate.

Photo Web Summit / Flickr(CC)