Enterprise Blockchain Platforms and Architecture
What this domain tests
Questions target platform architecture: Hyperledger Fabric, R3 Corda, and EVM-based enterprise chains such as Quorum and Besu. Know components, transaction flow, and where state and identity live.
Core rules
- Fabric separates execution from ordering: clients send proposals to endorsing peers; endorsements return read/write sets; the client submits to orderers; committers validate and update the world state.
- Fabric components: peers, orderers, channels, MSP, CA, chaincode, world state (LevelDB or CouchDB), ledger, and private data collections.
- Channels create separate ledgers and membership boundaries, not merely UI filters.
- Corda models bilateral agreements with states, flows, and notaries; it does not broadcast every transaction to every node.
- EVM enterprise chains reuse Solidity, accounts, gas, and JSON-RPC but often replace public consensus with IBFT or Raft and add permissioning.
Worked example
A 2-of-3 endorsement policy is set on a chaincode. A client proposes a transfer; peers A and B endorse, C does not. The client submits two endorsements. The orderer sequences the transaction; committers check the policy and read-set versions. If the asset key changed since endorsement, the transaction is marked invalid and the world state is not updated. The lesson: Fabric commits invalid transactions to the ledger for audit but does not apply their writes.
Traps
Fabric does not mine or charge gas. A channel is not a folder. Endorsement is not consensus - ordering and validation are separate. Corda is not a conventional global blockchain. Do not assume chaincode runs on orderers.