Protocol Architecture

Economic Protocol 📄

Consensus Protocol 🔏

In a distributed system a so called consensus protocol is required to establish agreement on the shared state/context of the system. Pending operations are bundled into a block. The rules of the Tezos protocol define who can produce blocks. This prevents individuals or groups to consecutively write blocks and to control what is included in the blockchain or replace parts. A central feature is that the rules prevent earlier blocks to be modified, because it would invalidate all subsequent blocks. The consensus mechanism protects the neutrality of the network.

The entity who creates the block is called in Tezos a baker👨‍🍳. The selection of the baker happens in a competitive/probabilistic manner and is rewarded with the fees contained in the block.

Updating the protocol through self-amendments 🔄

A unique feature that sets Tezos apart from other blockchain protocols is self-amendment through on-chain governance. It means that the underlying protocol can be replaced without interruption and hard fork. The process of governance, deciding which proposed protocol shall be used, happens through voting on-chain by XTZ stakeholders.

The voting process is divided into multiple steps that result in testing periods that allows the community to provide feedback and most importantly receive the approval of the majority. What is actually being voted on is a piece of code written in the programming language OCaml that codifies the protocol.1 After the voting ends the protocol is upgraded in a decentralized manner and the nodes operate as defined in the new piece of code.

Network protocol 📢

The gossip protocol is followed by the node. It is responsible for all communication among nodes, such as discovering, listening and broadcasting between peers.

Shell

The network shell glues together the blockchain and network protocol. It makes sure that both can communicate with each other seamlessly.

  1. This will change in the future, when the second implementation of Tezos, written in the programming language RUST, advances in development.↩
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