Vsock is a type of socket interface that is defined by a context ID (CID) and port number. The context ID is parallel to an IP address in a TCP/IP connection. Vsock utilizes standard, well-defined POSIX Sockets APIs (e.g. connect, listen, accept) to communicate with an enclave. Applications can use these APIs to communicate natively over vsock or they can send HTTP requests over vsock through a proxy. The Nitro Enclaves SDK includes examples on how you can program your application to send HTTP requests to your enclave.