Chapter 1. Local Area Network (LAN) Technologies

In this chapter:
LAN Encapsulations	3
Ethernet	4
Token Ring	15
FDDI	21
IEEE 802.11	26
Summary	30

To successfully troubleshoot Transmission Control Protocol/Internet Protocol (TCP/IP) problems on a local area network (LAN), it is important to understand how IP datagrams and Address Resolution Protocol (ARP) messages are encapsulated when sent by a computer running Windows Server 2008 or Windows Vista on LAN technology links such as Ethernet, Token Ring, Fiber Distributed Data Interface (FDDI), and Institute of Electrical and Electronics Engineers (IEEE) 802.11. For example, IP datagrams sent over an Ethernet network segment can be encapsulated two different ways. If two hosts are not using the same encapsulation, communication cannot occur. It is also important to understand LAN technology encapsulations to correctly interpret the Ethernet, Token Ring, FDDI, and IEEE 802.11 portions of the frame when using Microsoft Network Monitor.