[ryani]

That page claims it can compress a single transaction down to 12-16 bits. Unless the vast majority of btc transactions are between the same few wallet addresses, this seems impossible? Even if you assume that the transaction is an instance of a common known script, you still need from-address, to-address, and amount, all of which are >16 bit quantities and in general are cryptographically random.

The only explanation I can think of is that they are relying on a sidechannel to communicate the actual transactions, which makes sense in the miner case (the utxo pool) but not in the general node case.

Beyond that, I run a BTC node occasionally and the bottleneck is validating blocks, not downloading them. Transactions are complicated enough right now that I'm only able to catch up at about 350x real-time (that is, it takes around a full cpu-day to validate a year of blocks/transactions).