ETH Full/Dedicated ETH Node Documentation:
Websocket Support for Ethereum Nodes
Geth Websocket Connectivity
Connecting to a Dedicated Ethereum Node (JSON-RPC)
Connecting to a Shared Ethereum Node (JSON-RPC)
Allowed Ethereum RPC Commands
Why Do I Need an Ethereum Dedicated Node For the Ethereum Public Network?
How to Deploy a ETH RPC Node
Universal ETH API