Right now we're seeing cases where block propagation is sometimes taking minutes. This doesn't cause much of a problem for general Bitcoin users but for miners its problematic because it potentially increases the risk for orphaning.
There are probably many contributing factors which can be improved here but one of the most obvious is that nodes fully validate blocks before relaying them. The validation is IO intensive and can currently take a minute alone on sufficiently slow nodes with sufficiently large blocks and larger blocks require more data to be transmitted. Because this slowness is proportional to the size of the block this risks creating mismatched incentives where miners are better off not mining (many) transactions in order to maximize their income. The validation speed can and should be improved but there is at least one short term improvement that can be made at the protocol level: Make it possible to relay blocks to other nodes before fully validating them. This can be reasonable secure because basic validation (such as the difficulty, previous block identity, and timestamps) can be done first so an attacker would need to burn enormous amounts of computing power just to make very modest trouble with it... and it's a change which would be beneficial even after any other performance improvements were made. Luke has been working on a patch for this: https://github.com/luke-jr/bitcoin/commit/0ce6f590dc2b9cbb46ceecd7320220f55d814bca One aspect of it that I wanted to see more comments on was the use of a new message for the preview-blocks instead of just announcing them like normal. The reason for this is two-fold: To prevent existing full nodes from blacklisting nodes sending a bad preview block due to the existing misbehavior checks, otherwise an attacker could burn one block to partition the network, and also so that SPV nodes which aren't able to fully validate the block themselves can opt-out or at least know that the data is not yet validated by the peer. I don't see any better way to address this but I thought other people might have comments. ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
