There are three main types of LAN structures: Ethernet, Token Ring, Token Bus and FDDI, which are the backbone of these three networks. They follow 802-based standards developed by the IEEE (American Association of Electronic and Electrical Engineers). At present, there are 11 LAN-related standards. They are:

IEEE 802.1 - General Network Concept and Bridge, etc.

IEEE 802.2 - Logical Link Control, etc.

IEEE 802.3 - CSMA/CD Access Method and Physical Layer Provisions

IEEE 802.4 - ARCnet Bus Architecture and Access Method, Physical Layer Provisions

IE802.5-Token Ring Access Method and Physical Layer Provisions, etc.

IEEE 802.6 - Access Method and Physical Layer Provisions for Metropolitan Area Networks

IEEE 802.7 - Broadband LAN

IEEE 802.8-Fiber Local Area Network (FDDI)