Introduction to TCP/IP Networks:

Introduction to TCP/IP Networks:

TCP/IP-based networks play an increasingly important role in computer networks. Perhaps one reason for their

appeal is that they are based on an open specification that is not controlled by any vendor.

What Is TCP/IP?

TCP stands for Transmission Control Protocol and IP stands for Internet Protocol. The term TCP/IP is not limited just

to these two protocols, however. Frequently, the term TCP/IP is used to refer to a group of protocols related to the

TCP and IP protocols such as the User Datagram Protocol (UDP), File Transfer Protocol (FTP), Terminal Emulation

Protocol (TELNET), and so on.

The Origins of TCP/IP

In the late 1960s, DARPA (the Defense Advanced Research Project Agency), in the United States, noticed that there

was a rapid proliferation of computers in military communications. Computers, because they can be easily

programmed, provide flexibility in achieving network functions that is not available with other types of communications

equipment. The computers then used in military communications were manufactured by different vendors and were

designed to interoperate with computers from that vendor only. Vendors used proprietary protocols in their

communications equipment. The military had a multi vendor network but no common protocol to support the

heterogeneous equipment from different vendors

Net work Cables and Stuff:

In the network you will commonly find three types of cables used these are the, coaxial cable, fiber optic and twisted

pair.

Thick Coaxial Cable

This type cable is usually yellow in color and used in what is called thicknets, and has two conductors. This coax can

be used in 500-meter lengths. 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 Coaxial Cable

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As with the thick coaxial cable is used in thicknets the thin version is used in thinnets. This type cable is also used

called or referred to as RG-58. The cable is really just a cheaper version of the thick cable.

Fiber Optic Cable

As we all know fiber optics are pretty darn cool and not cheap. This cable is smaller and can carry a vast amount of

information fast and over long distances.

Twisted Pair Cables

These come in two flavors of unshielded and shielded.

Shielded Twisted Pair (STP)

Is more common in high-speed networks. The

biggest difference you will see in the UTP and

STP is that the STP use's metallic shield

wrapping to protect the wire from interference.

-Something else to note about these cables is

that they are defined in numbers also. The bigger

the number the better the protection from

interference. Most networks should go with no

less than a CAT 3 and CAT 5 is most

recommended.

-Now you know about cables we need to know

about connectors. This is pretty important and

you will most likely need the RJ-45 connector.

This is the cousin of the phone jack connector

and looks real similar with the exception that the

RJ-45 is bigger. Most commonly your connector

are in two flavors and this is BNC (Bayonet Naur Connector) used in thicknets and the RJ-45 used in smaller

networks using UTP/STP.

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 biggest reason that we call it Twisted Pair is to protect the wires

from interference from themselves. Each wire is only protected with a thin plastic sheath.

Ethernet Cabling

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Now to familiarize you with more on the Ethernet and it's cabling we need to look at the 10's. 10Base2, is considered

the thin Ethernet, thinnet, and thinwire which uses light coaxial cable to create a 10 Mbps network. The cable

segments in this network can't be over 185 meters in length. These cables connect with the BNC connector. Also as

a note these unused connection must have a terminator, which will be a 50-ohm terminator.

10Base5, this is considered a thicknet and is used with coaxial cable arrangement such as the BNC connector. The

good side to the coaxial cable is the high-speed transfer and cable segments can be up to 500 meters between

nodes/workstations. You will typically see the same speed as the 10Base2 but larger cable lengths for more

versatility.

10BaseT, the “T” stands for twisted as in UTP (Unshielded Twisted Pair) and uses this for 10Mbps of transfer. The

down side to this is you can only have cable lengths of 100 meters between nodes/workstations. The good side to

this network is they are easy to set up and cheap! This is why they are so common an ideal for small offices or

homes.

100BaseT, is considered Fast Ethernet uses STP (Shielded Twisted Pair) reaching data transfer of 100Mbps. This

system is a little more expensive but still remains popular as the 10BaseT and cheaper than most other type

networks. This on of course would be the cheap fast version.

10BaseF, this little guy has the advantage of fiber optics and the F stands for just that. This arrangement is a little

more complicated and uses special connectors and NIC's along with hubs to create its network. Pretty darn neat and

not to cheap on the wallet.

An important part of designing and installing an Ethernet is selecting the appropriate Ethernet medium. There are four

major types of media in use today: Thickwire for 10BASE5 networks, thin coax for 10BASE2 networks, unshielded

twisted pair (UTP) for 10BASE-T networks and fiber optic for 10BASE-FL or Fiber-Optic Inter-Repeater Link (FOIRL)

networks. This wide variety of media reflects the evolution of Ethernet and also points to the technology's flexibility.

Thickwire was one of the first cabling systems used in Ethernet but was expensive and difficult to use. This evolved tthin coax, which is easier to work with and less expensive.