Although certain techniques for protocol analysis benefit from manipulating live 'on-the-wire' interactions between communicating components, static or dynamic analysis techniques applied to executables as well as to device drivers, such as network interface drivers, can also be used to reveal the function and characteristics of a communication protocol implementation. Depending upon the methods used the process may involve observing, interacting, and modifying actual communications occurring between hosts. The goal of protocol analysis is to derive the data transmission syntax, as well as to extract the meaningful content, including packet or content delimiters used by the protocol. This type of analysis is often performed on closed- specification protocols, or proprietary protocols, but is also useful for analyzing publicly available specifications to determine how particular implementations deviate from published specifications.