General introduction of LAN and WAN

LAN:

• LAN (abbreviated from the English name Local Area Network, "local network") is a network used to connect computers in a small range (home, office, school, ...) . The computers on the LAN can share resources with each other, which typically share files, printers, scanners and other devices.
• A minimum required LAN server (server), the coupling device (Repeater, Hub, Switch, Bridge), the computer (client), network card (Network Interface Card - NIC) and cable (cable) to connect the computers together. In the era of MS-DOS operating system, LAN servers typically use Novell NetWare software, but this has become obsolete over after Windows NT and Windows for Workgroups appears. Today most servers use Windows operating systems, and LAN speeds up to 10 Mbps, 100 Mbps or even 1 Gbps.
• Another form of LAN as WAN (Wide Area Network). This means that wide-area network. Used to connect LANs together (via router).
• One other form of LAN, to appear in recent years as WLAN (Wireless LAN) - a wireless LAN.

• At the time before the personal computer appeared, a central computer occupies a room, users access the terminal server through data cable low speed. The Network of IBM SNA (systems network architecture) is focused on linking terminals or other mainframes at the remote site via the cable subscriber. From here it is the network is connected over large areas. The LAN (Local Area Network) was first created in the late 1970s and often creates high-speed links between several large central computers in one place. Many competing systems created at this time Ethernet and ARCnet is best known.
• The boom of the CP / M - And then the personal computer running DOS-based means that there are hundreds of computers can act alone and independently of the central computer. The initial appeal of the computer network that can share the drive ** a and the laser printer, which is both very expensive then. There are many exciting new concept and for several years, from about 1983 forward, the industrial informatics scholars regularly declare the coming year will be the year of the LAN.
• In fact, said it strongly shaken by the rapid increase of the different kinds of physical layer and network enforcement procedures are not compatible, and confusion about how to best share resources . Typically, each vendor has a style of their own network cards, cables, connection protocols, network operating system on their own. And an important solution appears with Novell NetWare names, their solution supports 40 different network card types, and an operating system more complex than most of its rivals. Networking software dominate the personal computer are connected (LAN) of the firm since early 1983 - when it was introduced - until the mid-1990s when Microsoft introduced advanced network operating system Windows NT Advanced Server and Windows for Workgroups (Windows for working group).
• The opponents of network software, only Banyan Vines have the skills to compete Switzerland but Banyan never have a secure position. Microsoft and 3Com worked together to create a simple network operating system, formerly of 3Com 3 + Share of Microsoft LAN Manager and LAN Server and IBM. No one in the number of particularly successful.
• In the same time frame with large workstations, UNIX workstations from vendors such as Sun Microsystems, Hewlett-Packard, Silicon Graphics, Intergraph, NeXT and Apollo using TCP / IP. Although the market segment for workstations running on UNIX has been falling but the technology was developed by them to continue to have influence over the Internet and in both Linux and Apple Mac OS X protocol TCP / IP is almost completely replaced IPX, AppleTalk, NetBEUI and other protocols used in early LANs were born.This stub.

Technical Description

• Although today's Ethernet switch is the most common protocols used in data link layer and IP is the most commonly used protocol in the Network layer, a lot of different options have been used, and a few of which became popular in the appropriate fields. Smaller LAN consists of one or more links to other network switches - often with a link to a router, cable modem or DSL modem for Internet access.
• The larger LAN is described by the user with redundant links and protocol conversion algorithm uses the tree to prevent loops, their ability to handle different types of traffic through quality dic service (QoS), and isolate traffic across VLANs. Larger LAN and also includes many diverse devices such as adapter, firewall, routers, load balancers, sensors and more.
• LAN can be linked to other local network via leased lines, subscription services, or by "tunneling" through the Internet using VPN technology. Depending on how to create and guarantee the bonds, and wide geographic network, the LAN system can become a master affiliate network (MAN) or wide area network links (WAN), or part Global Network.

The necessary equipment
Host (Server)
- As a computer with high-speed CPU, RAM and hard ** a large, usually associated with other peripherals such as printers (printer, scanner (scanner), ...).- Server is provided primarily for LAN resources.
Workstations

Cable

• - There are three types of cable commonly used: coaxial cable, twisted pair and fiber optics.
• - Coaxial cable: Includes two conductive layer coaxial with each other, separated by an insulating layer and the outer cover by a plastic shell. Conductive outer layer is usually metal mesh to prevent interference. There are two types of thick coaxial and thin coaxial cable.
• - Twisted: Composed of two strands twisted together, usually to divide the task of transmitting (sending a thread, a thread to receive data). There are two types is not shielded twisted pair (UTP and STP shielded twisted pair).
• - Cable: Made of glass or transparent plastic with a refractive index appropriate to ensure total reflection, outer shell also has a more reflective, light form data is transmitted with a loss less.
• Network Card
• As a special hardware device in your computer, also known as Network Interface Card, Network Card or LAN Adapter. Card belongs to the physical layer and data link layers of the OSI model, give each computer a physical address (MAC Address) single, recorded in the ROM of the card to the computer to distinguish each other.
• The equipment associated
• The main equipment is the repeater (Repeater), bridge (Bridge), Hub, Switch.

                                                                                                                                           

                                                                                Lan                                                         

Wan Network:  

• WAN is a data exchange network, it operates beyond the physical range of the LAN.WAN works on a large geographical domain, connect computer systems across pWhen the computer networks of scale development is also at the geographical distancemust be extended, then the LAN does not meet the technical requirements for the expansion of computer networks poses a problem ... the transmission distance, a LAN is limited to small areas such as in an office or building, to connect sites in widely separated locations, WAN bor

• In LAN we have known devices such as hubs, switches .. the Ethernet protocol, 802.3,802.2 devices and these are the basic protocol, how about the WAN, the star model
• The answer is that there are devices and protocols of its own, because to an information system is operational, the two factors: equipment and protocols is indispensable.
• Here I will present some key equipment and protocols in the WAN:rovinces, countries or continents ... 
• Router: Router is a device used for routing, a router can connect to LAN-LAN, LAN-WAN, LAN-Internet, a router to work will require the router operating system IOSIOS will have different each other, and the router will have a different IOS version. Somecommon types of routers on the market. Your reference

And many more, in this framework is not presented his all, of you to google search will bemore intuitive, in general, there are many manufacturers, but their assessment of theCisco router as well as quality features pretty good. 

• WAN switch: Switch the children do not mistake this full-fledged divisional LAN Switch,Switch Layer 2 LAN switch is a switch in the WAN is also Layer3 switch (it even has a routing function.) 

Switch model in the WAN 

• CSU / DSU: CSUDSU (channel / data sevice unit) is equipment that allows data channels are digital interface to connect a router to a digital circuit such as T1, CSU / DSU also provides signal on the time communication between two devices connected through the CSU / DSU is 

CSU / DSU Motorola 




Some communications behind a CSD / DSU 

• ISDN terminal adapter: An ISDN terminal adapter is used to connect ISDN Basic Rate Interface (BRI) to a port on the router interfaces such as EIA/TIA-232. Although it is called a Terminal Adapter, but it can not convert from analog signals to digital signals is.

ISDN terminal adapter of its Blackbox

•  Modem: is using the generic name for the device to convert signals from analog to digital and vice versa, allowing voice transmission, (Modem is Modulation and demodulation of the abbreviated)

                                                                                                                 

Wan