NETWORK

To connect a computer with a network we need NETWORK ADAPTER

The network adaptor is an interface that connect computers. It is plugged in to the motherboard expansion slot.

It is also named : Network Interface Card (NIC). LAN Card. LAN Adapter.

We could summarize the jobs of the (NIC)as following: Prepare data to send it through network. Send data to network. Control the speed of data between the computer and other devices. Translate the electric sign that comes through cables to bytes to be recognized by the CPU, also translate the Bytes from the computers to electric sign through cables.

ADDRESSES The Institute of Electrical and Electronic Engineers which is known as (IEEE) Gives unique address to every industry that manufactures NIC. Every NIC address contain 48 bits that is memorized inside the NIC’s ROM. The first 24 bits express the manufactory and the other 24 bits express the serial number of the card. Each NIC send its unique number to all devices in the network to recognize it. Each NIC contain of Hardware and Firmware (software) that is responsible for the NIC duties.

It is known that data pass inside a computer through buses. Every Bus contains number of lanes that allow big amount of data to pass so fast. In a previous time the buses could send just 8 bits then it is developed to send 16 then 32 and afterward it becomes able to send 64 bits. This kind of transmitting data is called PARALLEL TRANSMISSION and the other kind is called SERIAL TRANSMISSION which is used in cable. The NIC’s transceiver is responsible for changing the transmission from serial to parallel and from parallel to serial.

HOW DOSE (NIC) SEND DATA?

First of all, the NIC sends a request to the CPU. The CPU sends data through Buses. Generally, the speed of data from the CPU to the NIC is faster than the speed of data from the NIC to other devices, so some data should be saved in the RAM until it could be send by the NIC. This technique is named Buffering.

Identifying Each Other

All the NIC should identify each other. Every NIC send its ability to connect with others rightly. If one of the NIC faster, it should connect slowly with the slower.

Things That should be allocated between NIC: The maximum packets size. Time between packets. The speed of transmission data.

Things that is done by NIC: Controlling connection. Requesting packets. Verifying address. Find error and solve it.

LINKS and DATA CONNECTION Network Cables

There are three well known kinds of network cables as following: Twisted Pair cables. Coaxial Cables. Fiber Optic Cables.

Twisted Pair Cables It is similar to telephone cables, but a bit bigger. It contain of twin coppery thin cables. Cables are twisted to reduce sign errors.

Types of Twisted Cables There are two types of twisted cables: STP Shielded Twisted Pair and UTP Unshielded Twisted Pair

Unshielded Twisted Pair (UTP) This is the most popular form of cables in the network and the cheapest form that you can go with. The UTP has four pairs of wires and all inside plastic sheathing. The reason that we call it Twisted Pair is to protect the wires from affecting each other. Each wire is only protected with a thin plastic sheath.

Shielded Twisted Pair (STP) It is more common in high-speed networks. The biggest difference between UTP and STP is that the STP use's metallic shield wrapping to protect the wire from interference.

UTP Cable

It is used in a variety of networks. Each of the eight individual copper wires in UTP cable is covered by an insulating material. In addition, the wires in each pair are twisted around each other.

UTP cable is easy to install and is less expensive than other types of networking media. In fact, UTP costs less per meter than any other type of LAN cabling. And because UTP can be used with most of the major networking architectures, it continues to grow on.

Disadvantages Disadvantages also are involved in using twisted-pair cabling, however. UTP cable is more prone to electrical noise and interference than other types of networking media, and the distance between signal boosts is shorter for UTP than it is for coaxial and fiber-optic cables.

features of UTP cable: Speed 10 to 1000 Mbps Average cost per node—cheapest Media and connector size—Small Maximum cable length—100 m (short)

Commonly used types of UTP cabling are as follows: Category 1: Used for telephone communications. Not suitable for transmitting data. Category 2: Used for LocalTalk& Telephone (Rarely used). Capable of transmitting data at speeds up to 4 megabits per second (Mbps). Category 3: Used in 10BASE-T networks. Can transmit data at speeds up to 10 Mbps. Frequency up to 16MHz

Category 4: Used in Token Ring networks(Rarely used). Can transmit data at speeds up to 16 Mbps. Frequency up to 20MHz Category 5: Can transmit data at speeds up to 100 Mbps. Frequency up to 100 MHz Category 5e: Used in networks running at speeds up to 1000 Mbps (1 Gbps). frequency up to 100 MHz

RJ-45 connectors

COAXIAL CABLE It similar to Satellite Receiver Cable and it has several shapes, but the most popular are the thin and thick Ethernet cable.

Thick Ethernet Coaxial Cable It is more protected than the Thin one and it is able to send a packet to 500m, also it is known as the backbone of the network, because it connects all network branches. This cable is usually yellow in color and used in what is called thicknets. The cable itself is made up of a solid center wire with a braided metal shield and plastic sheathing protecting the rest of the wire.

Thin Ethernet Coaxial Cable It is less protected than the thick cable and it is able to send a packet to 185m.It is used in thinnets. This type is also called RG-58. The cable is really just a cheapest version of the coaxial cable.

Parts That Connect Coaxial Cables.

Fiber Optic Cable: It is a uniqu cable that send data through light rather than copper. It sends data from 1 to 2 Gigabyte Per second depending on the area. There is no electric conflicts. High security.

Cables 10BASE-T (Twisted cable with a maximum segment length of 100 meters) 10BASE-2 (Thinwire coaxial cable with a maximum segment length of 185 meters)coaxial cable 10BASE-5 (Thickwire coaxial cable with a maximum segment length of 500 meters) 10BASE-F (optical fiber cable)optical fiber