Network flow

What are the data exchanged between the nodes?

Nodes relay the operations (transfers, SC origination, ...) and blocks they receive (or sometimes create) from other nodes. Since the nodes can't be trusted, they also check every information they receive. They communicate only with a subset of all the nodes in the network that can vary over time.

What are the nodes default ports?

The main port which the node is listening on by default is 9732.