RTS XCP-48-RJ45 Manuel d'utilisateur télécharger pdf (Page 46)

The four numbers in and IP Address are used in different was to identify a particular network and host on

that network. There are three classes of Internet Addresses.

CLASS A - supports 16 million hosts on each of 127 networks.

CLASS B - supports 65,000 hosts on each of 16,000 networks.

CLASS C - supports 254 hosts on each of 2 million networks.

LAN

A LAN is a computer network that connects a relatively small area (a single building or group of buildings).

Most LANs connect work stations and computers to each other. Each computer (also known as a “node”),

has its own processing unit and executes its own processing unit and executes its own programs; however it

can also access data and devices anywhere on the LAN. This means that many users can access and share the

same information and devices. A good example of a LAN device is a network printer. Most companies

cannot afford the budgetary or hardware expense of providing printers for each of its users; therefore, one

printer (i.e., device) is placed on the LAN where every user can access the same printer.

The LAN uses IP Addresses to route data to different destinations on the network. An IP Address is a 32-bit

numeric address written as four numbers separated by periods (for example 1.160.10.240).

Port

A port, when referring to TCP and UDP networks, is an endpoint in a logical connection. The port number

identifies the type of port it is. For example, port 80 is used for HTTP traffic.

Routers

A router is a device that forwards data packets over networks. Most commonly, a router is connected to at

least two networks (normally LANs or WANs). Routers are located at gateways, the place where two

networks are connected. Routers do little data filtering, they mainly deliver the data.

Subnet

A subnet is a portion of a network that shares a common address component. On a TCP/IP network, a subnet

is described as all computers or devices whose IP Address have the same prefix.

Subnetting a network is useful because it provides security for the network as well as increases performance

of the network. IP networks are divided using subnet masks.

Switches

A switch is a device that filters and forwards data packets between networks. Switches operate at the data

layer, and sometimes at the network layer.

WAN

A wide area network connects two or more LANs and can span a relatively large geographical area. For

example, Telex Headquarters in Burnsville, MN is connected to several of its branch offices in Nebraska and

Arkansas over the wide area network. The largest WAN is the Internet.

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RTS XCP-48-RJ45 Manuel d'utilisateur Page 46