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I'd like to read about the difference between these terms: Node, Peer and User.

From what I understand, a node is basically a machine which inside is running the HL Fabric binaries and is communicating with other machines belonging to the same network. A peer is the type of the node, in particular:

  • Orderer: the one which put the transactions in a certain order for the insert in the ledger.
  • Endorser: this type is the one that runs the chaincode and produces the RW sets.
  • Commitment: a peer that propagates valid transaction among the network.

Finally, a user is a subject that has a digital certificate and exists in some organization. More users can work on the same node / peer.

Please tell me if there is something wrong in what I wrote and, eventually, why is that wrong.

giacom0c
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1 Answers1

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Your definition of a user is correct. I think the below graphic from the Hyperledger Fabric paper should be helpful toward understanding the word 'peer'.

  • Node: Generic term for any type of application that is part of the Fabric network. A node in a Fabric network can be one of three things: Client, Peer or Ordering Service Node (Orderer)

  • Peer: Every peer maintains a copy of the ledger. The peers execute a consensus protocol to validate transactions, group them into blocks, and build a hash chain over the blocks. A peer may be an endorser for a specific chaincode, but doesn't have to be.

    • Endorser: Part of every peer. Runs the chaincode and produces the RW sets.
    • Committer: Part of every peer. Performs validation of transactions after ordering
    • Ledger: Part of every peer. Stores blockchain state and history.
  • Orderer: Separate instances responsible for reaching consensus on the order of transactions, i.e. Raft based
  • Client: Submits transaction proposals to peers, specifically those peers that are endorsers for the relevant chaincode
  • User: Has a valid user certificate issued by an MSP. Creates transactions using a client to interact with chaincode.

To gain a thorough understanding of each of these I recommend reading the full paper yourself.

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Sigmatics
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