Section VII
Optimum
Bandwidth-Optimal Networking
Optimum breaks every block into coded pieces and spreads them across the network. Any sufficient handful rebuilds the whole, so blocks survive heavy loss and still arrive. Far less travels than in flooding, and the network runs near its capacity even under loss.
rlnc fundamentals
RLNC Fundamentals
Ordinary networks send you numbered pieces of a file and you collect them until you have them all. Miss one and you ask for that specific piece again, and you wait for it while everything else sits finished.
Coded networking deletes the idea of a specific piece. A block is turned into coded fragments, and no fragment is the original, none is a backup, and none matters more than another. Collect any sufficient handful and the block rebuilds.
It stops mattering which pieces arrive. Only how many.
rlnc properties
Three Key Properties
Three properties, and the first is the one that makes coded gossip work for a blockchain rather than for a file transfer.
A relay can generate fresh coded pieces out of the pieces it already holds, without unpacking anything first. So a node three hops out is not sitting idle while a node two hops out finishes assembling something. Everyone forwards useful data the moment they have any at all.
- Relay without decoding: a node can forward fresh coded pieces it never had to unpack, so multi-hop delivery stays cheap
- Loss tolerance: any sufficient set of pieces recovers the block, under any pattern of drops
- Near-zero overhead: only a small coding tax rides on top of the payload
mump2p
The mump2p Protocol
mump2p is the protocol that runs coded gossip as a live mesh.
Pieces flow outward. Peers suppress duplicates instead of dutifully rebroadcasting them. Whatever a node is missing, it pulls. The block decodes the instant enough fragments have arrived, from whoever happened to have them.
There is no designated path a block travels along, which means there is no path an attacker can sit on and wait.
optimality
Capacity-Approaching Throughput
Traditional gossip sends the same data down every edge and hopes. On a well-connected network most of what crosses the wire is a duplicate of something that already arrived, and the better connected the network gets, the more it wastes.
Optimum approaches the network's information-theoretic capacity. That phrase means something specific: there is no protocol that moves this data with less bandwidth. Not a faster one we have not written yet — none.
And it holds under packet loss, which is exactly when flooding designs degrade worst and exactly when a blockchain most needs its blocks to arrive.
network security
Network Security
Every coded piece is signed by the producer that made it.
Coded networking has one obvious attack: inject a single corrupted fragment and you poison every reconstruction it takes part in. Checking the signature on arrival closes it. A forged shard is discarded at the first hop and the sender is pruned from the mesh.
The cost of that check is one verification per fragment. The cost of skipping it is the whole block.