For simplicity and to avoid the usage of mTLS, which is not well supported by all network infrastructure, each BFT ordering node (client endpoint) opens its own P2P connection to every other server endpoint, performs server authentication and then pushes messages to it.

Note that the Java gRPC implementation seems to implement unidirectional streams as bidirectional ones, which seems to require anyway at least one server-sent message before completion (according to https://github.com/grpc/grpc-java/issues/6568). Using a unidirectional stream and sending an empty response from the server results in Netty reference-counted buffer leaks.