Networking Devices and their functions

Have you ever wondered when sending an e-mail how your data gets transferred from one computer to another all the way across the world? Let me introduce Networking devices and their jobs that give us the satisfaction of getting our data to the right destination. The major functions of these networking devices are storage,in and out put, and the ability to process data.

• Client/ Server Model • Routers • Switches • Hubs • Modems • Servers • NIC Card

Client/Server model

Think of each individual computer operating system serving as a Client/Server Model.This model processes data through networking ports, protocols, and services.

Servers

Servers have applications that are assigned ports that run in the back ground listening and waiting for a request from the client. Client applications are what a client uses to start the communication process. For example, when you want to send an E-mail you are working with a client application that is going to talk to the web server, when you want to print you are interacting with the print client that talks to a printer server. Each computer serving this model recognizes the assigned port numbers that go with the services.The server stores information that can be shared by others it can be located anywhere and does not need a screen to display. Now that you know a little about the server it is important to know a little about the software that is also responsible for our data transfer.Networking devices operate around the software that is responsible for our data transfer.

TCP/IP

is the software that interacts with the client/Server models. Before TCP/IP can work with devices, every device on the internet must be assigned a unique address if you want to connect outside of your network. TCP/IP packages and arranges our data into binary bits which are zeros’ and one’s and is digital form; a computer language.When a client is using an application and sends it off to its destination, seven layers are responsible,right down to the wire transfer going across the Internet into another network router. Through each layer of TCP/IP protocols and control information is added to give the user security,reliability as well as error messaging when undelivered. A single user can use multiple services at a time because of assigned port destination which allows the server to directly talk with Client application. When data reaches the destination device this will do a reverse process through the seven layers to unpack your data. Protocols are rules integrated within applications and services that control our data transfer through TCP/IP. For Example, a web browser is a client application that asks a web server for the web page uses HTTP protocol. This in turn creates a process. These are the application layer protocols that provide the exchange of data these are waiting and listening:

• DNS: Domain name system Port 53

• HTTP: File transfer of web pages Port 80

• SMTP: (SMTP) client/ send e-mail port 25

• POP2: protocol for receiving e-mail port 110

• DHCP: port 67

• FTP: Use for file transfers port 20, 21

• Telnet- connect remotely to a PC port 23

NIC Networking Interface card

offers you your internet speed and uses a port RJ/45 UTP cable, looks similar to a phone connector which is a RJ/11.This card gives you physical access to the medium. NIC cards have a Mac address used to direct traffic across the internet. This device can be an add on with older computers. A NIC,or network interface card,allows your computer to connect to a network where all the systems are physically cabled together.

Modems

A Modem is categorized by the service it performs. Sometimes people mistake routers with modems,so it can be confusing to think of a router and modem. Modems connect you with your Internet ISP (Internet Service Provider). Normally by DSL, Cable, and Dial Up. Modem translate analog to Digital,reverses the action into the destination modem. All networking devices require a Modem to talk through a telephone line such as e-mail service to the ISP. Modems receive the electrical signal & transport it to the router at the data link layer two of TCP/ IP. The receiving computer's modem must answer the call, referred to as"handshake"to establish communications,and signal its computer to be ready to receive. When this is done the modems are in a state referred to as "connected".

Hubs

Hubs are used to share data between multiple devices on a section of the network all devices connected to the hub share bandwidth. Bandwidth is the capacity of data entering the wire .it can connect to a switch or a router. Hubs and Switches do the same kind of work other than switches pay attention to the traffic going into individual computers that have assigned port numbers. Switches eventually replaced hubs as a group of users grew.

Switches

Switches filter and separate network traffic sending data to the port that the computer is destined for. Switches keep attract of all the devices connected to it called a routing table.Switches allow your network to grow. Each device has individual bandwidth capability that the interface offers. Hubs, Switches and Routers are all devices’ that let you connect to one or more computers, networked devices, or to extend networks.Router is complicated of any hub or switch.

Router

Router sets between ISP network (Internet Service Provider) local network, routing traffic between different networks. Router takes the place of a host computer providing the gateway to the Internet when using a modem. Each port on the router connects to a different network, therefore stops congestion. If your create subnets of your network the router will identify whether you are a remote computer or in the local network by the subnet mask it will be assigned by your ISP. Routers keep the data flowing through the Internet and considered a gateway outside of your network. It is assigned a special gateway address. A router keeps attract of every IP address of each host computer associated with their Mac address that is located on the computer NIC card. Routers have additional features like security, serving as a switch, or wireless access point. Many routers have a default address, reached by opening your web browser to access the internet then type in the IP address in form of 192.168.1.1 or 192.168.0.1. This will allow you to access the Router or Modem Utility settings to adjust the features. (You also might need the pass word as well)To name a few:

• DHCP service on port 67 a feature that dynamically assigns IP addresses.

• Restriction of Internet use/unwanted traffic can be blocked.

• Use Access restrictions by using port filtering and port forwarding by IP address.

• Set policies for different groups of users.

• Routers also serve as a hardware firewall that serves as security.

To learn more about the TCP/IP or the OSI model click here____________________