TCP

• layer on top of TCP
• The WebSocket API (WebSockets) - Web APIs | MDN

Hypertext Transfer Protocol (HTTP) is an application-layer protocol for transmitting hypermedia documents, such as HTML. It was designed for communication between web browsers and web servers, but it can also be used for other purposes. HTTP follows a classical client-server model, with a client opening a connection to make a request, then waiting until it receives a response. HTTP is a stateless protocol, meaning that the server does not keep any data (state) between two requests. Though often based on a TCP/IP layer, it can be used on any reliable transport layer, that is, a protocol that doesn't lose messages silently like UDP does. RUDP - the reliable update of UDP - is a suitable alternative.

• HTTP/1.0 explained

Query/Response protocol which allows a client to access dictionary definitions from a set of natural language dictionary databases.

port 2628

For many years, the Internet community has relied on the "webster" protocol for access to natural language definitions. The webster protocol supports access to a single dictionary and (optionally) to a single thesaurus. In recent years, the number of publicly available webster servers on the Internet has dramatically decreased.

Fortunately, several freely-distributable dictionaries and lexicons have recently become available on the Internet. However, these freely-distributable databases are not accessible via a uniform interface, and are not accessible from a single site. They are often small and incomplete individually, but would collectively provide an interesting and useful database of English words. Examples include the Jargon file, the WordNet database, MICRA's version of the 1913 Webster's Revised Unabridged Dictionary, and the Free Online Dictionary of Computing. (See the DICT protocol specification (RFC) for references.) Translating and non-English dictionaries are also becoming available (for example, the FOLDOC dictionary is being translated into Spanish).

The webster protocol is not suitable for providing access to a large number of separate dictionary databases, and extensions to the current webster protocol were not felt to be a clean solution to the dictionary database problem.

The DICT protocol is designed to provide access to multiple databases. Word definitions can be requested, the word index can be searched (using an easily extended set of algorithms), information about the server can be provided (e.g., which index search strategies are supported, or which databases are available), and information about a database can be provided (e.g., copyright, citation, or distribution information). Further, the DICT protocol has hooks that can be used to restrict access to some or all of the databases.