What is the difference between consecutive and simultaneous interpreting?

Most interpreting is done in the consecutive mode: speaker speaks, pauses, interpreter repeats what was said in the other language referring to notes taken in shorthand. Simultaneous or conference interpreting is a more demanding mode of interpreting where speaker and interpretation happens in real time with no delay. This mode is used in the United Nations (remember Nicole Kidman in the movie, The Interpreter). International conferences around the world rely on the skill of teams of simultaneous interpreters to get important messages across to delegates. It is not possible to use consecutive interpreters in a conference format - you need double the amount of time for starters; secondly if more than two languages are involved, as is often the case with international conferences, teams of interpreters relay the speech into their respective languages. Sometimes this involves what is known as relay interpreting. For example the speaker speaks in Azeri, the Azeri interpreters interpret into English from where the other teams (could be multiple languages) then interpret into their respective languages. Such interpreting relies on the expertise of the interpreters; if one link breaks, all delegates miss out.