There's three fundamental network protocols at play with bitcoin: Node discovery, transaction broadcasting, and consensus. Node discovery and transaction broadc

There's three fundamental network protocols at play with bitcoin: Node discovery, transaction broadcasting, and consensus. Node discovery and transaction broadcasting are "easy" gossip protocol problems. It's the consensus that's novel, and that's where blocks, proof-of-work, etc come into play. The gossip protocol for transaction broadcasting ensures that the whole network will see (almost) all transactions before they're published in a block.