Types of network

    从不同的角度对网络有不同的分类方法，每种网络名称都有特殊的含意。几种名称的组合或名称加参数更可以看出网络的特征。了解网络的分类方法和类型特征，是熟悉网络技术的重要基础之一。我们经常听到局域网，城域网，广域网等，他们是如何分类的呢，下面将用英语为大家介绍一下按照网络地理位置网络有哪些基本常见类型。
    In the simplest sense, networking means connecting computers so that they can share files, printers, applications, and other computer-related resources. One way to categorize the different types of computer network designs is by their scope or scale. For historical reasons, the networking industry refers to nearly every type of design as some kind of area network. Common examples of area network types are:

    This type of network can range from a few desktop workstations in a Small Office/Home Office (SOHO) to several thousand workstations and dozens of server deployed throughout dozens of buildings on a university campus or in an industrial park. The computer systems are linked with cables. In LAN system computers on the same site could be linked. In TCP/IP networking, a LAN is often but not always implemented as a single IP subnet.
    In addition to operating in a limited space, LANs are also typically owned, controlled, and managed by a single person or organization. They also tend to use certain connectivity technologies, primarily Ethernet and Token Ring.

    A network spanning a physical area larger than a LAN but smaller than a WAN, such as a city. A MAN is typically owned an operated by a single entity such as a government body or large corporation. It spans an urban area and are generally run by service providers to provide companies with high-speed connectivity between branch offices and with the Internet.

 
    As the term implies, a WAN spans a large physical distance. The Internet is the largest WAN, spanning the Earth. A WAN is a geographically-dispersed collection of LANs. A network device called a router connects LANs to a WAN. In IP networking, the router maintains both a LAN address and a WAN address.
    A WAN differs from a LAN in several important ways. Most WANs (like the Internet) are not owned by any one organization but rather exist under collective or distributed ownership and management. WANs tend to use technology like ATM, Frame Relay and X.25 for connectivity over the longer distances.

    While LAN and WAN are by far the most popular network types mentioned, you may also commonly see references to these others:
Wireless Local Area Network - a LAN based on WiFi wireless network technology.
    Campus Area Network - a network spanning multiple LANs but smaller than a MAN, such as on a university or local business campus.
    Storage Area Network - connects servers to data storage devices through a technology like Fibre Channel.
    System Area Network - links high-performance computers with high-speed connections in a cluster configuration. Also known as Cluster Area Network.

 
    categorize vt.把…归类;把…列作
    subnet n.子[分支]网络
    Ethernet n. 以太网
    token ring令牌网
    span 跨越、横跨
    entity n.实体, 独立存在体, 实际存在物.统一性
    geographically-dispersed地理位置分散的群集