UNIX System Management: the concept and composition of LAN

To complete this chapter, you can do the following things:

Understand the role of local LAN

Understand the concept and role of the OSI model

Understand the meaning of host name, IP address, MAC address, port, and socket in the OSI model.

Understand the format and function of MAC addresses.

Understanding the format and role of IP addresses

Understanding the format and role of host names

Understand the differences between UDP and TCP protocols.

Understanding the role of ports and sockets

Understand the search process for host names from IP addresses to MAC addresses.

1.1 What is a local area network (LAN)?

Type of connection maximum distance

SCSI bus 5m

Local area network (LAN) 5 km

Wide Area Network 500 km

There are many ways of communication in the computer field. Some modes of communication are used locally, such as SCSI devices, with a distance limit (5 m). Other means of communication, such as the two systems through a network of dialogue, to achieve a further distance.

Today, the network is usually divided into LAN and WAN based on the geographical coverage. The two main networks are:

LAN (LANS) These http://www.aliyun.com/zixun/aggregation/18415.html "> network connected devices are within a localized range (not exceeding 5 km).

Wide area Network (WANS) These networks cover a large geographical area, and a city's equipment can communicate with equipment in another city.

Both types of networks are based on the same principle. And it's all about achieving the same goal, but using a lot of different techniques.

Lan

The following is the definition of LAN in IEEE 802:

A local area network is a data communication system that allows independent devices to communicate with each other. The limitations of LAN include: Private network, must be connected through continuous media, support low-speed and high-speed data communication.

The local area network is:

A broadcasting mechanism

Connected by a continuous medium

Composed of independent devices and able to communicate with each other

A communication system that shares resources, such as data files, applications, and external devices (printers, scanners, and backup devices)

Geographical limitations: not exceeding 10 km

High speed transmission of large amount of information (for example, Ethernet can reach 10Mbps, optical fiber can reach 100Mbps)

Wan

A wide area network covers a larger geographic area and supports lower data transfer speeds (typically no more than 1Mbps). A phone line is typically used to connect to a remote computer on two networks. Typical wide area networks such as ARPANET and public X.25 nets.