Scaling IOTA Part 1 - A Primer on Sharding

Motivation

Reasons and workarounds for this limitation

  1. Delegate all the computation to a smaller set of very powerful nodes (i.e. Hashgraph, EOS and so on …).
  2. Split the tasks and make each node only perform a subset of the total amount of work.

Additional problems with sharding

  • Running multiple chains in parallel requires consensus on the number of shards, and changing this number is not possible “on-the-fly”. To be future-proof it is necessary to split the network into more shards than the current throughput requires, which results in reduced security from day one. It is impossible for the network to organically react to growing adoption or to different network conditions.
  • Since the throughput in every shard is defined by system parameters like block size and block times, every node needs to fulfill certain hardware requirements, which prevents low-powered IoT devices from taking part in the network.
  • Since we cannot arbitrarily increase the number of shards (at some point the beacon chain gets overloaded), this solution also does not offer real infinite scalability with the number of nodes.

IOTAs Vision

Requirements for IOTA’s Vision

  • The solution has to incorporate some form of sharding, since micro-optimizations are merely delaying the problems rather than solving it.
  • The solution should prevent double-spending without relying on some complicated form of inter-shard communication (see the video mentioned above).
  • The network should only shard if it is really necessary, maintaining as much security of the system as possible in times of low activity but at the same time being able to grow with rising adoption.
  • The sharding layout has to be dynamic enough to instantly react to changes in the network without nodes having to “talk” to each other to negotiate a new sharding layout or use fees to determine which transactions to favor (agent-centric approach).
  • The sharding should use a “meaningful mapping” of the real world (i.e. geographic mapping) so that nodes that are close to each other are always able to directly communicate without having to use some complicated form of inter-shard communication.
  • Nodes should be able to individually decide how much and which data they want to process so that we can have a heterogeneous network with low-powered IoT devices alongside more powerful nodes.
  • Nodes should be able to freely move around between shards (mobile nodes like cars) without having to suddenly download and validate huge amounts of data.

Conclusion

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Hans Moog

Hans Moog

I am a hacker, feminist, futurist and tech enthusiast working for IOTA and trying to make the world a better place (whatever that means) :P