Adam,the download time must be MUST lower than the block interval.
Otherwise, the reorgs will be too high.
Do you get that?
reorgs?
with new block propagation being trivial thanks to "Corallo Relay Network" we only need nodes to be able to keep up with the TPS
so if every user on the network can
comfortably download 100MB in 10mins, there shouldn't be any problem using 100MB as the block limit
actually there WOULD be a problem if block were bigger than this limit, which is what the limit should be about in the first place.
Blockchain reorgs.
The reason why proof-of-work and the longest chain rule are effective in maintaining distributed consensus,
is that the time between blocks is much bigger than the time it takes to broadcast a block to the network.
If two miners find a block at about the same time and start broadcasting them to about half the network
each, you have a fork. One half is on one chain, and one half is on another. It gets resolved by the
longest chain rule when the next block is found. Since the winning blocks takes only a few seconds
to reach the network, the fork is quickly resolved. However, if the blocks take a long time to broadcast,
then more competing blocks are going to be solved and broadcast. I hope you get my point, but it
is clear to me that a huge difference in broadcast time vs block time is necessary for the longest chain
rule to maintain order, minimize reorgs and prevent network splits. The longer the time, the more reorgs and the more
problems you will get. Would a full minute be ok for broadcast times? Probably, although reorgs will
increase. Several minutes? Now its starting to be a real issue. 10 minutes? No way.