The protocol is composed of two layers. The SSL Record Protocol is used for encapsulation of various higher level protocols. One such encapsulated protocol, the SSL Handshake Protocol, allows the server and client to authenticate each other and to negotiate an encryption algorithm and cryptographic keys before the application protocol transmits or receives its first byte of data. One advantage of SSL is that it is application protocol independent. A higher level protocol can layer on top of the SSL Protocol transparently.
Encryption is used after an initial handshake to define a secret key.
The connection is reliable. The browser and server exchange data via secret key encryption during that session. The session is then managed by a security protocol. Articles dsniff and SSH, Reports of My Demise are Greatly Exaggerated by Richard E. Silverman. A response to Kurt Seifried's article.