C# SNMP Library (#SNMP) - Open source SNMP implementation for C#
HTTP and WebSocket built on Boost.Asio in C++11
nanomsg library
Cross-platform, C implementation of the IETF QUIC protocol
Gev is a lightweight, fast non-blocking TCP network library
An Open Source POWERLINK Stack
A cross-platform network component developed by WeChat
Java asynchronous socket library
Lightweight fully extendable client/server application framework
Networking/Socket C++ Library.
HTTP request utility designed with developers in mind.
Actor based programming using WCF and async-await.