|  | 2.3 | How WANs relate to the OSI Model
| 2.3.1 | Organizations that deal with WAN standards

WANs use the OSI reference model layered approach to encapsulation, just as LANs do, but they are mainly focused on the physical and data link layers. WAN standards typically describe both physical-layer delivery methods and data link-layer requirements, including addressing, flow control and encapsulation. WAN standards are defined and managed by a number of recognized authorities, including the following agencies: International Telecommunication Union-Telecommunication Standardization Sector (ITU-T), formerly the Consultative Committee for International Telegraph and Telephone (CCITT) International Organization for Standardization (ISO) Internet Engineering Task Force (IETF) Electronic Industries Association (EIA) Telecommunications Industries Association (TIA)