The Russian president and the Chinese counterpart need to come to an agreement by telephone. Neither can speak and understand each other's language. They need to employ translators. Compare this layered communication to OSI layers (Application of the material in Chapter 1 of the Textbook). The presidents are similar to applications. The messages they generate go through translators. This is similar to the OSI Presentation layer. The messages exchanged may go through some kind of encryption to protect them from eavesdroppers. Since the communication is going through a telephone line, it is a case of connection oriented communication. Since the telephone line might be a dedicated secure line, it is similar to a point-point to communication. Error checking plays major role in this application; the translations have to be true to the domain of application and specific enough to avoid any future misunderstandings. The conversations will most probably be saved for later verification and comparisons.