GIRAPH-12 considered replacing the current Hadoop based rpc method with Netty, but didn't went in another direction. I think there is still value in this approach, and will also look at Finagle.
Port Giraph to YARN
remove hadoop RPC and keep just netty
Add secure authentication to Netty IPC
CommunicationsInterface shouldn't implement VersionedProtocol
BasicRPCCommunications shouldn't implement both CommunicationsInterface and ServiceInterface