NETWORK COMMUNICATION DEVICES

An Internet service provider (ISP), also sometimes referred to as an Internet access provider (IAP), is a company that offers its customers access to the Internet. The ISP connects to its customers using a data transmission technology appropriate for delivering Internet Protocol packets or frames, such as dial-up,DSL, cable modem, wireless or dedicated high-speed interconnects.
ISPs may provide Internet e-mail accounts to users which allow them to communicate with one another by sending and receiving electronic messages through their ISP's servers. ISPs may provide services such as remotely storing data files on behalf of their customers, as well as other services unique to each particular ISP.

from: http://en.wikipedia.org/wiki/Internet_service_provider

There are a lot of internet service provider (ISP) in Malaysia.Which of the ISP is best to use?
Streamyx
P1 Wimax
YES 4G
Maxis Broadband
Digi Broadband
Celcom Broadband


Please leave your comment ya ^^

Sunday, March 6, 2011

Network Communications Devices

A network is consists of a larger number of the communication devices. The simplest device that is used in the communication is the NIC adapter which is attached with the every computer in a network. If you want to build a LAN, you will need to have computers, hubs, switches, network adapters, UTP/STP cables, routers, internal/external modems, connectors, cable testers and clipping tool.

On the other hand if you need to build WAN, you will need to have routers, switches, dedicated or leased telephone lines such as ISDN lines, frame relay connection and other types of wan communication connections. There are different communication mediums such as Ethernet cables, copper wire, coaxial cable, fiber optic cables, leased telephone lines and ever air is also a communication medium for the satellite communication. The most common networking medium is the LAN is the Ethernet cable (UTP/STP), which is used in the star topology. Hub is a central device of a network and every computer in a network is directly connected with the hub.

If the hub fails to work, the communication between the computers stops till the hub again starts working. Hub broadcasts the data to its every port, and then finding the destined computer, the data sent toward it. The switch is an advance form of the hub similar in functions but the advanced switches has a switching table in them. A advanced switch stores the MAC address of every attached computer and the data is only sent to the destined computer, unlike the hubs where data is sent to all ports. A router is a key device in the internet communication and wan communication system. A router has software called routing table and the source and destination addresses are stored in the routing table.

A router connects two logically and physically different networks. Router finds the IP address of the next hop (next router) and the data is sent toward it and so on. The well known routers developing companies are Cisco systems, Nortel, DLink and others. Every ISP, banks, corporate offices and multinational companies use routers for LAN and WAN communications and communication in their private networks. A gateway can be device or software in a network.

A gateway device connects the LAN with the internet. A gateway is directly exposed to the internet so it should be securely configured and in and out traffic should be monitored. If you are using DSL connection, you must need a DSL modem in your network. The telephone line is connected with the DSL modem and UTP/STP cable attaches your computer with the DSL modem. Modems are the devices that are used to modulate and demodulate the data. They convert analogue signals to digital and digital signals to analogue so that signals can travel on the telephone lines.

There are certain types of the cables that are used to connect two or more computers in a network. Fiber optic cable acts as a backbone between the ISPs and corporate offices. Data travels at the speed of light on the fiber optic cables. The cost and the installation cost of the fiber optic cable is very high but it is becoming very popular in the home networking and LANs also. In the local area networking, 10baseT/CAT5 cable is most commonly in use.

A server is a computer in network that provides services to the client computers such as logon requests processing, files access and storage, internet access, printing access and many other types of services. Servers are mostly equipped with extra hardware such as plenty of external memory (RAM), more data store capacity (hard disks), high processing speed and other features.

from: http://www.networktutorials.info/communication_devices.html

Network Communications

Communication Protocols

It is very interesting to know that how computers send and receive the information across the communication links. Computers do this job by the help of data communication software. It is software that enables computers to communicate with each other. The data transmission software tells the devices and computers how to send information to the other computers. The software that is used for the data transmission is known as protocol. The data transmission software or protocols perform the following basic functions:


1. Data sequencing: A long message is broken up into the smaller packets of fixed size for the error free transmission.
2. Data Routing: In the data routing process the most efficient route is to find to send the data from the source to the destination.
3. Flow control: The flow control regulates the process of sending data between fast sender and slow receiver.
4. Error Control: Error detection and recovery is the most important factor of the data transmission software (protocols). It ensures the error free transmission of the data.


from: http://www.networktutorials.info/communication .html

Saturday, March 5, 2011

CONNECTION DEVICES

Connecting devices allow hardware devices to communicate with each other. The most popular example of connecting devices nowadays is wireless connections. Wireless devices transfer and receive information through infrared or radio waves. The three kinds of wireless connections are Bluetooth, infrared, and WiFi(wireless fidelity). It is most frequently used in business andpersonal computer environments. Connecting devices, especially Wireless devices, bring convenience to our life and work.

Wireless connecting devices

Bluetooth

Bluetooth uses short-range radio waves over distances of 9 metres. For example, Bluetooth devices such as a keyboard, PDA, cell phone, mouse or computer can connect to each other wirelessly and the distance can be up to 10 meters (33 feet). Some of the Bluetooth devices can support headsets and printers.

Infrared

Infrared also called IR or IrDA (Infrared Data Association) has a frequency below what our eye can see. It is broadly used in infrared light, cell phone and TV remotes. IR wireless is used in wireless technology in devices or systems that convey data through infrared radiation, for instance, infrared wireless printing or infrared keyboards.

WiFi

WiFi (wireless fidelity) uses radio waves for connection over distances up to around 91 metres, usually in a network environment. Wifi can be used to connect Local Area Networks [LAN], to connect cellphones to the Internet to download music and other multimedia, to allow PC multimedia content to be stream to the TV (Wireless Multimedia Adapter), and to connect video game consoles to their networks (Nintendo WiFi Connection).