The smallest unit on the Internet is the individual user. In many offices and homes, each person has her own personal computer. In other organizations, there may be a very large computer that each member of the organization has an individual account on. In any case, it is important to imagine that each individual has a userid within the local organization, and that all the computers within this organization are tied together with some sort of local area network. Often each department or floor in an organization has a LAN. LANs usually consist of up to 100 computers attached together through wires and special software so they can communicate easily. Often, LANs are tied together within a large organization to make WANs, or Wide Area Networks. For our discussion, we will consider LANs and WANs to be pretty much the same thing.