IOTA 3.0 – Additional improvements
The coordinator is shut down and the IOTA network is fully decentralized. This topic collects the subsequent improvements to the protocol.
IOTA nodes have an upper limit on transactions per second (TPS) they can process. Through a form of database partitioning (breaking a very large database into smaller ones) into more manageable segments (shards) each shard would contain a unique set of account balances and nodes would then be assigned to individual shards to validate transactions.
The goal is to increase transaction throughput by splitting the Tangle into more manageable segments. The trilemma will continue to exist within individual shards, but as soon as the network throughput exceeds the processing capacities of the nodes in a single shard, another shard will be formed dynamically (fluid sharding). Due to the novel very flexible sharding, theoretically infinite high transaction speeds are possible with IOTA.
The multiverse consensus is an alternative to the Fast Probabilistic Consensus, which will be introduced with Coordicide. The multiverse consensus is an idea of Hans Moog, one of the developers of the IOTA Foundation and has not yet been researched in detail.
Hans Moog describes his consensus in a single sentence:
“If we find an efficient way of ‘encoding’ our votes publicly in the tangle (in form of transactions) and allow nodes to reach consensus using a form of ‘virtual voting’, then this would make a lot of things much easier.”
Blockchain tracks a single ledger state of a single chain. Blocks are valid only if they do not contain double-spends and block producers act as gatekeepers controlling which messages are added to the ledger state. Nodes track the “consensus outcome.”
In a DAG-based DLT, such as IOTA, there are no block producers and anyone can add anything to the underlying data structure at any time without asking anyone else for permission – even double-spends. Each double issue introduces a different version of the ledger state, which may or may not be compatible with other versions introduced by other transactions. IOTA has developed a data structure – the parallel reality-based ledger state – that allows it to efficiently track all these different versions (realities) simultaneously. It tracks the ledger state “before consensus.”
Since duplicate issues can occur in the underlying data structure, similar to other DAG-based DLTs, IOTA uses a voting mechanism (FPC) where nodes exchange opinions to come to an agreement on which messages should be “accepted” by the Tangle.
Due to its unique ledger state, unlike other DAG-based DLTs, IOTA does not need to vote on non-conflicting messages, but only on the conflicting ones, which significantly reduces message overhead.
Multiverse consensus now goes a step further and uses the underlying data structure itself as a voting mechanism. Each message issued by a node already contains the opinion of that node, since it issues certain funds belonging to a certain reality, and it also approves 2 or more other messages in the DAG that also belong to a certain reality. So the opinion of the issuing Nodes is already known without having to ask them. In theory this allows the IF to get rid of the additional voting mechanism (FPC) that would set the message overhead for voting to 0. Of course this needs further research and testing.
This is tantamount to the “original vision” of IOTA, where the only thing nodes need to do is issue messages and consensus is reached automatically.
To hedge the tangle, nodes with a lot of weight (mana) in the consensus process can send a single transaction every now and then, which is replicated via gossip, rather than having to respond to requests from a potentially unlimited number of other nodes. This is not only much more efficient, but also much safer, since each node has the same view of things and the nodes can never come to a different conclusion.
This is essentially the idea behind Multiverse and why it is called what it is.
According to Hans Moog the main advantages of the Multiverse Consensus are:
- Less “moving parts” and much easier to implement
- Orders of magnitude more secure
- Smaller message overhead
- No need for re-attachments and promotions
- Completely partition tolerant and resilient against large scale network splits
- Works in the IoT and mesh net environment
- Independent of the amount of “bad nodes” in the network
- Does not require a specific network topology
You can view Hans coding a version of his Multiverse Consensus. Especially the first 35 minutes are very interesting when he talks about problems of the Tangle in the past and how these will change.
Last Updated on 14. June 2021