TCP/IP

TCP and IP were developed by a Department of Defense (DOD) research project to connect a number different networks designed by different vendors into a network of networks (the "Internet"). It was initially successful because it delivered a few basic services that everyone needs (file transfer, electronic mail, remote logon) across a very large number of client and server systems. Several computers in a small department can use TCP/IP (along with other protocols) on a single LAN. The IP component provides routing from the department to the enterprise network, then to regional networks, and finally to the global Internet. On the battlefield a communications network will sustain damage, so the DOD designed TCP/IP to be robust and automatically recover from any node or phone line failure. This design allows the construction of very large networks with less central management. However, because of the automatic recovery, network problems can go undiagnosed and uncorrected for long periods of time.

As with all other communications protocol, TCP/IP is composed of layers:

IP - is responsible for moving packet of data from node to node. IP forwards each packet based on a four byte destination address (the IP number). The Internet authorities assign ranges of numbers to different organizations. The organizations assign groups of their numbers to departments. IP operates on gateway machines that move data from department to organization to region and then around the world.

TCP - is responsible for verifying the correct delivery of data from client to server. Data can be lost in the intermediate network. TCP adds support to detect errors or lost data and to trigger retransmission until the data is correctly and completely received.

Sockets - is a name given to the package of subroutines that provide access to TCP/IP on most systems.

Fiber-Optic Cable

It is a cabling technology that uses optical fibers to carry digital data signals in the form of modulated pulses of light. The core of fiber-optic cable is made of glass or plastic and the cladding that are enclosed by a protective coating. Outer insulating jacket is made of Teflon or PVC. Kevlar fibers are used to strengthen the cable and prevent from breakages.

A brief overview of the advantages of fiber-optic cable over coaxial and twisted pair:

Speed: Fiber optic networks operate at high speeds in the gigabits range.

Bandwidth: High-capacity data transmission.

Distance: Due to lack of attenuation Signals can be transmitted over long distances without using repeaters.

Resistance: Greater resistance to outside interferences such as radios, motors and electromagnetic noise.

Expensive and very fragile.

Twisted Cables

The twisting of two insulated wires around each other is known as twisted pair cables. Cables that use twisted pair of wires reduce the Crosstalk between them to a great extent.
As shown in the image, the pair of wires may be surrounded either by a shield, or similar pairs of wires. Each pair is uniquely color coded when packaged in multiple pairs. Different uses such as Analog, Digital, and Ethernet require different pair multiples.

Twisted pair wiring is commonly used to connect telephones and in computer network technology and are classified according to their maximum transmission frequencies. Today, there are basically only two types used and they are Cat3 and Cat5.

Some features of Twisted pair cabling are:
It is flexible and easy to terminate.
For Cat 5e/6/7 UTP the maximum segment length is 100 meters.

10BaseT refers to the specifications for unshielded twisted pair cable (Category 3, 4, or 5) carrying Ethernet signals. Category 6 is relatively new and is used for gigabit connections.

Twisted pair cables are available in two variants:
Shielded Twisted Pair (STP) and
Unshielded Twisted pair (UTP)

Plenum Cable

Plenum grade cable is a cable that uses fire resistant material such as Teflon for insulation. This type of material in the insulation minimizes the amount of smoke in case of fire. However, plenum cabling are more expensive and less flexible than a PVC cable. This type of cable is generally used in space reserver for air circulation in air conditioning and heating systems

Coaxial Cable

Coaxial cable is commonly used in the cable television industry. This has also gained popularity in use for computer networks, such as Ethernet networks. Coaxial cable is highly resistant to signal interference and can support greater distance between network devices than twisted pair cable.
Coaxial cable consists of a single core copper wire surrounded by an insulator and enclosed in a copper mesh, finally covered inside an outside insulation

The main features co-axial cable:
When compared to twist pair cable a coaxial cable can support greater cable ths between network devices.
They are highly resistant to signal interference.
It costs less that other cables.
Not flexible and it is more difficult to terminate.

Types of Cable

A cable is a group of insulated conductors enclosed within an Insulator. The main function of a cable is transmitting signal from one point to another. They can be broadly categorized into 5 types depending on their attenuation, cost, immunity to EMI, skilled labor required for installation etc.
Given below is the list of cable types used in networking.

Coaxial
RG6
RG8
RG58
RG59

Plenum/PVC

UTP
CAT3
CAT5/e
CAT6

STP

Fiber
Single-mode
Multi-mode

Networking Cable

Cable is the medium through which data is transmitted from one network device to another. There are several types of cables, which are commonly used with LANs. The growth of Local Area Networks (LANs) and client server computing has produced a great increase in the amount of cabling used.
In many cases, a network will use a variety of cable types. The type of cable chosen for a network is related to the network's topology, protocol, and size. Also the common transmission losses such as attenuation have to be taken care of while choosing the type of cable used.