Constellation is a protocol for Multiple Concurrent Proposers (MCP) on Solana. It achieves the fastest protocol-enforced, censorship-resistant economic tick of any decentralized blockchain in production. Censorship resistance comes from erasure coding, the same technology that powers Solana's Turbine block delivery system. Constellation is a proposal planned for implementation by Anza in the Agave client.
Cycles & Blocks
Users send transactions to one or multiple proposers. During each cycle (50ms), each proposer includes a set of transactions and sends erasure-coded pslices as pshreds to the attesters.
Each attester timestamps and forwards all pshreds to the leader, accompanied with an attestation. Per cycle, the leader compiles all transactions with enough attestations that fit the sequential compute limit of a batch.
The batches of all cycles of one slot constitute the payload of the leader's block. Validators check correctness and vote via Votor.
Aggregate Attestation Matrix
Constellation relies on erasure coding, the same underlying technology that powers Turbine, to guarantee censorship resistance. If enough attesters have seen shreds for a proposal, it MUST be included in the next execution cycle. To see how this works, toggle attestations to see which proposer blocks are included.
Each column is an attester. Each row is a proposer. Toggling a cell represents an attester attesting to that proposer’s commitment. Click an attester header to enable/disable that attester’s attestation column without forcing every proposer to be attested. The block is skipped if attester attestations fail the 60% threshold. If a proposer misses the 40% threshold, only that proposer’s block is excluded.
Protocol constants
SUMMARY
The constellation protocol calls for 16 proposers, 256 Attesters and a single leader in each slot. Attesters act as a timeliness comitee on a 50ms wall clock cadence. Each validator has a local sychronized clock that they use for attestation timings and only for attestation timings. The rest of the protocol does not rely on this synchronized wallclock at all.