PCH9 Network Overview(網路總覽) << Previous Next >> Network Defined by Relationships(關係定義的網路)

Network Defined by Geography(地理定義的網路)

Overview

In this module, we are going to cover the various types of networks, including local area networks, wide area networks, personal area networks, and metropolitan area networks. Next, we will cover the various network relationships, such as client/server and peer-to-peer, and focus on the types of resources our networks use. Finally, we will talk about the topologies of our networks, such as the bus, the ring, the star, the full mesh, and hybrid network topologies.

總覽

在本模塊中，我們將涵蓋各種類型的網絡，包括局域網，廣域網，個人局域網和城域網。接下來，我們將介紹各種網絡關係，例如客戶端/服務器和對等網絡，並集中討論網絡使用的資源類型。最後，我們將討論網絡的結構，例如總線，環形，星形，全網格和混合網絡結構。

Network Defined by Geography

Networks are defined by the geography they cover. We start with the area around a single person, with this area being termed the personal area network (PAN). Next, we expand outward to the local area network (LAN), which can contain an entire office floor or building. Moving outward again, we have the metropolitan area network, which covers the area across the city by connecting multiple LANs together. Finally, we have the wide area network (WAN). This is the largest network we define by geography and it can go across the country or even across the world. A great example of a WAN is the Internet, since it connects many networks together and stretches across the globe.

地理定義的網路

網絡由它們所覆蓋的地理位置定義。我們從一個人周圍的區域開始，將該區域稱為個人區域網絡（PAN）。接下來，我們向外擴展到局域網（LAN），該局域網可以包含整個辦公樓層或建築物。再次向外移動，我們有了城域網，該城域網通過將多個LAN連接在一起而覆蓋了整個城市。最後，我們有廣域網（WAN）。這是我們按地理位置定義的最大網絡，它可以遍及全國，甚至遍及全球。 WAN就是一個很好的例子，因為Internet將許多網絡連接在一起並遍及全球。

Geographic networks. Image used under CC-BY license from Jason Dion.

地理網絡。圖片由Jason Dion根據CC-BY許可使用。

Personal Area Network

A PAN has a very small range limited to just a few meters. If you stretch your hands out at your sides and spin around in a circle, this is the physical range of most PANs. Bluetooth is one of the main things we use to create a PAN, although USB and infrared can also be used for these networks. Bluetooth has a range between one meter and 100 meters depending on which class of Bluetooth you are using, but most common Bluetooth devices are class two devices limited to 10 meters. Some good examples of PANs are the connection between a USB hard drive and a laptop, or a Bluetooth cellphone connecting to your car stereo system wirelessly.

個人區域網

PAN的範圍很小，只有幾米。如果您將雙手伸向兩側並轉一圈，則這是大多數PAN的物理範圍。藍牙是我們用於創建PAN的主要內容之一，儘管USB和紅外也可以用於這些網絡。藍牙的範圍在1米至100米之間，具體取決於您使用的藍牙類別，但是大多數常見的藍牙設備是限於10米的第二類設備。 PAN的一些很好的例子是USB硬盤驅動器和筆記本電腦之間的連接，或者是無線連接到汽車立體聲系統的藍牙手機。

Local Area Network

The next type of network defined by geography is the LAN, which stands for local area network. The local area network is comprised of several devices that allow computers to connect to each other within a small geographic area. A LAN is, at its most basic, a connection of several workstations together using a hub, switch, or wireless access point. LANs have a limited distance associated with them, with each network segment usually limited to 100 meters or less. Generally, a LAN is used to network the floor of an office, or possibly the entire office building in smaller networks. LANs are generally connected in either a wired or wireless manner. If wired, they are connected using unshielded twisted pair cable using the Ethernet (IEEE 802.3) standard; if wireless, they are connected using Wi-Fi radio signal (IEEE 802.11) standards.

區域網路

地理定義的下一種網絡類型是LAN，它代表局域網。局域網由幾個設備組成，這些設備使計算機可以在一個較小的地理區域內相互連接。局域網最基本的是使用集線器，交換機或無線訪問點將多個工作站連接在一起。局域網的距離有限，每個網段通常限制在100米或更短。通常，LAN用於將辦公室地板或較小網絡中的整個辦公樓聯網。 LAN通常以有線或無線方式連接。如果已連接，則使用符合以太網（IEEE 802.3）標準的非屏蔽雙絞線電纜進行連接；如果為無線，則它們使用Wi-Fi無線電信號（IEEE 802.11）標准進行連接。

image2.png (198×204)

Simple LAN diagram. Public domain image obtained from Wierzbadark.

簡單的局域網圖。從Wierzbadark獲得的公共領域圖像。

Caption. Complex LAN diagram. Used with permission. Copyright: ohmega 1982/123 RF Stock Photo.

Metropolitan Area Networks

Another way we can geographically define our networks is as a MAN. A metropolitan area network connects scattered locations across the city or county. This covers a larger geographical area than a local area network, but also a much smaller area than a wide-area network.

城域網

我們可以在地理上定義網絡的另一種方法是將其作為MAN。城域網連接整個城市或縣的分散位置。這比局域網
覆蓋更大的地理區域，但是比廣域網覆蓋的區域小得多。

MAN diagram. Image used under CC-BY-SA license from Greta Bynum.

城域網圖。圖片由Greta Bynum根據CC-BY-SA許可使用。

Wide Area Networks

The WAN is used to connect network components that are geographically separated over vast distances together. An example of a WAN would be to connect an office in Los Angeles to another corporate office in New York. This can be done using virtual private networks (VPNs) over the Internet or using dedicated leased lines that would physically connect the city pairs together. Regardless of the method of connection, once the two local area networks from Los Angeles and New York are connected, they become part of the larger wide area network topology.

廣域網

WAN用於將地理位置遙遠的網絡組件連接在一起。 WAN的一個示例是將洛杉磯的辦公室連接到紐約的另一公司辦公室。這可以通過Internet上的虛擬專用網絡（VPN）或使用將城市對實際連接在一起的專用租用線路來完成。無論採用哪種連接方法，來自洛杉磯和紐約的兩個局域網一旦連接，它們便成為更大的廣域網拓撲的一部分。

Wide area network, metropolitan area network, and local area network. Image used under CC-BY-SA license from Suwimon bunmak.

廣域網，城域網和局域網。圖片來自Suwimon bunmak的CC-BY-SA許可。

PCH9 Network Overview(網路總覽) << Previous Next >> Network Defined by Relationships(關係定義的網路)