Client/Node

Specification & Implementations

Yellow paper : http://gavwood.com/paper.pdf

Implementations in various languages. C++: eth, Python: pyethapp, golang: geth (most popular)

Peer-to-peer protocol: DEVp2p, TCP based messaging protocol, default port 30303

Dapp to Client/Node protocol (Peer) :

• IPC-RPC (default, considered much more secure than JSON-RPC, for local Dapp)
• JSON-RPC (http://localhost:8545)
• WS-RPC

JS API Console

• Attach a console to client/node and use Web3 API to invoke various functions

Client function

• Connect to peers to receive data
  1. Receive data
  2. Validate
  3. If validated, save to local database (file system)
  4. Sends blocks if requested from another peer
• Participate in mining process
  • Dapp/wallet simply send a command to let client/node start mining
• Serve Dapp
  • Dapp send transactions to client/(or)node
    • send/receive ether
    • deploy contract
    • execute contract
  • Node propagate to network
• Serve explorer with history
• Execute smart contract functions

Client storage size

https://dev.to/5chdn/the-ethereum-blockchain-size-will-not-exceed-1tb-anytime-soon-58a

https://ethereum.stackexchange.com/questions/143/what-are-the-ethereum-disk-space-needs

See the effect of different modes and storage size