RFC 2817: "Upgrading to TLS Within HTTP/1.1", explains how to use the Upgrade mechanism in HTTP/1.1 to initiate Transport Layer Security (TLS) over an existing TCP connection.
RFC 2817: “Upgrading to TLS Within HTTP/1.1" (’Peningkatan TLS dalam HTTP/1.1'), menjelaskan bagaimana penggunaan mekanisme upgrade dalam HTTP/1.1 untuk menginisialisasi Transport Layer Security melalui koneksi TCP yang ada.