Monday, 23 March 2015

Practical Number 1

Practical Number 1

Computer network components

Computer network components include the major parts that are needed to install a network both at the office and home level. Before delving into the installation process, you should be familiar with each part so that you could choose and buy the right component that fits with your network system.
These hardware components include cableHubSwitchNIC (network interface card), modem and router. Depending on the type of network you are going to install, some of the parts can be eliminated. For example, in a wireless network you don’t need cables, hubs so on.
In this article we will discuss about the main computer network components required to install simple computer network, often called LAN (local area network).
Computer network is a group of two or more computers that connect with each other to share a resource. Sharing of devices and resources is the purpose of computer network. You can share printers, fax machines, scanners, network connection, local drives, copiers and other resources.
In computer network technology, there are several types of networks that range from simple to complex level. However, in any case in order to connect computers with each other or to the existing network or planning to install from scratch, the required devices and rules (protocols) are mostly the same.

Major computer network components
Computer network requires the following devices (some of them are optional):-
• Network Interface Card (NIC)
• Hub
• Switches
• Cables and connectors
• Router
• Modem

1. Network Interface Card
Network adapter is a device that enables a computer to talk with other computer/network. Using unique hardware addresses (MAC address)encoded on the card chip, the data-link protocol employs these addresses to discover other systems on the network so that it can transfer data to the right destination.
There are two types of network cardswired and wireless. The wired NIC uses cables and connectors as a medium to transfer data, whereas in the wireless card, the connection is made using antenna that employs radio wave technology. All modern laptop computers incorporated wireless NIC in addition to the wired adapter.

Network Card Speed
Network Interface card, one of the main computer network components, comes with different speeds, 10Mbps, 100Mbps, and 1000Mbps, so on. Recent standard network cards built with Gigabit (1000Mbps) connection speed. It also supports to connect slower speeds such as 10Mbps and 100Mbps. However, the speed of the card depends on your LAN speed.
For example, if you have a switch that supports up to 100Mbps, your NIC will also transfer a data with this same speed even though your computer NIC has still the capability to transfer data at 1000Mbps (1Gbps). In modern computers, network adapter is integrated with a computer motherboard. However if you want advanced and fast Ethernet card, you may buy and install on your computer using the PCI slot found on the motherboard (desktop) and ExpressCard slots on laptop .

2. Hub
Hub is a device that splits a network connection into multiple computers. It is like a distribution center. When a computer request information from a network or a specific computer, it sends the request to the hub through a cable. The hub will receive the request and transmit it to the entire network. Each computer in the network should then figure out whether the broadcast data is for them or not.
Currently Hubs are becoming obsolete and replaced by more advanced communication devices such as Switchs and Routers.

3. Switch
Switch is a telecommunication device grouped as one of computer network components. Switch is like a Hub but built in with advanced features. It usesphysical device addresses in each incoming messages so that it can deliver the message to the right destination or port.
Like Hub, switch don’t broadcast the received message to entire network, rather before sending it checks to which system or port should the message be sent. In other words switch connects the source and destination directly which increases the speed of the network. Both switch and hub have common features: Multiple RJ-45 ports, power supply and connection lights.

4. Cables and connectors
Cable is one way of transmission media which can transmit communication signals. The wired network typology uses special type of cable to connect computers on a network.
There are a number of solid transmission Media types, which are listed below. - Twisted pair wire
It is classified as Category 1, 2, 3, 4, 5, 5E, 6 and 7. Category 5E, 6 and 7 are high-speed cables that can transmit 1Gbps or more. -
Coaxial cable
Coaxial cable more resembles like TV installation cable. It is more expensive than twisted-pair cable but provide high data transmission speed.
Fiber-optic cable
It is a high-speed cable which transmits data using light beams through a glass bound fibers. Fiber-optic cable is high data transmission cable comparing to the other cable types. But the cost of fiber optics is very expensive which can only be purchased and installed on governmental level.

5. Router
When we talk about computer network components, the other device that used to connect a LAN with an internet connection is called Router. When you have two distinct networks (LANs) or want to share a single internet connection to multiple computers, we use a Router.

In most cases, recent routers also include a switch which in other words can be used as a switch. You don’t need to buy both switch and router, particularly if you are installing small business and home networks.
There are two types of Router: wired and wireless. The choice depends on your physical office/home setting, speed and cost.

Practical Number 8

Practical Number 8

Steps for installing Proxy Server on Windows

1.       Put the Proxy Server CD in the drive.
2.      Change to the CD-ROM directory.
You will see the following directories:
o    /Documentation
§  /Licenses
§  /Linux-x86
§  /Solaris-sparc
§  /Solaris-x86
§  /Windows
In /Linux-x86, /Solaris-sparc,/Solaris-x86, and /Windows directories you will see the following files:
§  /ProxyServer
§  README.txt
§  setup
You can run the setup program in the GUI, CLI, or silent mode.
Installing From the Web Site

Steps for installing Proxy Server on Windows

1.       Download the installation file from and save it in a temporary directory in your Windows system.
A progress bar indicates the status of the download.
2.      Change to the directory where you have downloaded the installation zip file that is in the following format:
3.      Unzip the .zip file to extract its contents to the chosen folder.
When the extraction is complete, you will see a /ProxyServer directory and the following files:
o    LICENSE.txt
o    README.txt
o    setup

You can run the setup program in the GUI, CLI, or silent mode.

Practical Number 7

Practical Number 7

Network Troubleshooting

What does Network Troubleshooting mean?

Network troubleshooting is the collective measures and processes used to identify, diagnose and resolve problems and issues within a computer network.
It is a systematic process that aims to resolve problems and restore normal network operations within the network.

Network Troubleshooting

Network troubleshooting is primarily done by network engineers or administrators to repair or optimize a network. It is generally done to recover and establish network or Internet connections on end nodes/devices.

Some of the processes within network troubleshooting include but are not limited to:

·         Finding and resolving problems and establishing Internet/network connection of a computer/device/node
·         Configuring a router, switch or any network management device
·         Installing cables or Wi-Fi devices
·         Updating firmware devices on router switch
·         Removing viruses
·         Adding, configuring and reinstalling a network printer

Network troubleshooting can be a manual or automated task. When using automated tools, network management can be done using network diagnostic software.

Practical Number 6

Practical Number 6

 Network Protocol - Types of Network Protocols

Network Protocol is a set of rules that governs the communications between computers on a network.

What is a Network Protocol

Rules of Network Protocol include guidelines that regulate the following characteristics of a network: access method, allowed physical topologies, types of cabling, and speed of data transfer.

Types of Network Protocols

The most common network protocols are:
·         Ethernet
·         Local Talk
·         Token Ring
·         FDDI
·         ATM
The followings are some commonly used network symbols to draw different kinds of network protocols.
The Ethernet protocol is by far the most widely used one. Ethernet uses an access method called CSMA/CD (Carrier Sense Multiple Access/Collision Detection). This is a system where each computer listens to the cable before sending anything through the network. If the network is clear, the computer will transmit. If some other nodes have already transmitted on the cable, the computer will wait and try again when the line is clear. Sometimes, two computers attempt to transmit at the same instant. A collision occurs when this happens. Each computer then backs off and waits a random amount of time before attempting to retransmit. With this access method, it is normal to have collisions. However, the delay caused by collisions and retransmitting is very small and does not normally effect the speed of transmission on the network.
The Ethernet protocol allows for linear bus, star, or tree topologies. Data can be transmitted over wireless access points, twisted pair, coaxial, or fiber optic cable at a speed of 10 Mbps up to 1000 Mbps.

Fast Ethernet
To allow for an increased speed of transmission, the Ethernet protocol has developed a new standard that supports 100 Mbps. This is commonly called Fast Ethernet. Fast Ethernet requires the application of different, more expensive network concentrators/hubs and network interface cards. In addition, category 5 twisted pair or fiber optic cable is necessary. Fast Ethernet is becoming common in schools that have been recently wired.

TCP - Transmission Control Protocol

TCP is one of the main protocols in TCP/IP networks. Whereas the IP protocol deals only with packets, TCP enables two hosts to establish a connection and exchange streams of data. TCP guarantees delivery of data and also guarantees that packets will be delivered in the same order in which they were sent.
Local Talk
Local Talk is a network protocol that was developed by Apple Computer, Inc. for Macintosh computers. The method used by Local Talk is called CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance). It is similar to CSMA/CD except that a computer signals its intent to transmit before it actually does so. Local Talk adapters and special twisted pair cable can be used to connect a series of computers through the serial port. The Macintosh operating system allows the establishment of a peer-to-peer network without the need for additional software. With the addition of the server version of AppleShare software, a client/server network can be established.
The Local Talk protocol allows for linear bus, star, or tree topologies using twisted pair cable. A primary disadvantage of Local Talk is low speed. Its speed of transmission is only 230 Kbps.

Token Ring
The Token Ring protocol was developed by IBM in the mid-1980s. The access method used involves token-passing. In Token Ring, the computers are connected so that the signal travels around the network from one computer to another in a logical ring. A single electronic token moves around the ring from one computer to the next. If a computer does not have information to transmit, it simply passes the token on to the next workstation. If a computer wishes to transmit and receives an empty token, it attaches data to the token. The token then proceeds around the ring until it comes to the computer for which the data is meant. At this point, the data is captured by the receiving computer. The Token Ring protocol requires a star-wired ring using twisted pair or fiber optic cable. It can operate at transmission speeds of 4 Mbps or 16 Mbps. Due to the increasing popularity of Ethernet, the use of Token Ring in school environments has decreased.

Fiber Distributed Data Interface (FDDI) is a network protocol that is used primarily to interconnect two or more local area networks, often over large distances. The access method used by FDDI involves token-passing. FDDI uses a dual ring physical topology. Transmission normally occurs on one of the rings; however, if a break occurs, the system keeps information moving by automatically using portions of the second ring to create a new complete ring. A major advantage of FDDI is high speed. It operates over fiber optic cable at 100 Mbps.

Asynchronous Transfer Mode (ATM) is a network protocol that transmits data at a speed of 155 Mbps and higher. ATM works by transmitting all data in small packets of a fixed size; whereas, other protocols transfer variable length packets. ATM supports a variety of media such as video, CD-quality audio, and imaging. ATM employs a star topology, which can work with fiber optic as well as twisted pair cable.

ATM is most often used to interconnect two or more local area networks. It is also frequently used by Internet Service Providers to utilize high-speed access to the Internet for their clients. As ATM technology becomes more cost-effective, it will provide another solution for constructing faster local area networks.

Practical number 5

Practical number 5

How to Create a Local Area Network (LAN)

A LAN, or local area network, is a great way to share files and devices between multiple computers. If you have several computers in your home, setting up a network will allow you to share an Internet connection, data, printers, and other devices between your computers - all without wires. Fortunately, the process is simple, and you can learn how to set up a LAN in your home by following a few easy steps.
Assess your needs in a network. The devices you use to set your network up will determine your network's capabilities. You should address your needs in terms of cost, security, connection speed, expandability (adding more computers or devices later) and distance between computers. In general, you will need to keep all the computers in the network within 100 yards (91 m) of each other.

Ensure that your computers have wireless networking cards installed. In order to communicate wirelessly with other computers in the network, each computer must have a wireless networking card. If your computers are only a few years old, you are almost guaranteed to already have one built-in, as this is a standard feature on all computers being produced today. If you have an older computer, you may need to purchase and install a networking card.

Set up an Internet connection. While LANs can be set up simply to share files between computers without Internet connectivity, there is little benefit to doing so considering the cost of wiring the entire network. To share an Internet connection between computers, you will first need a broadband Internet connection (such as cable or DSL) set up for your primary computer. Contact a local Internet service provider (ISP) to establish a connection if you don't already have one.

Purchase a wireless router. You will need to broadcast your Internet connection wirelessly, and for this, you need a router. When buying a router, make sure you get one that is designed for your connection type (cable, DSL, etc.). You should also consider the strength of the router's signal. The packaging will describe how far you can expect the router's signal to broadcast. It will need to reach every computer in your network.

Install the router. To install the router, run your main Ethernet cable (the one used for connecting your primary computer to the Internet) from your modem into the router. Plug the router's power cord in, and then install any software that it came with on each computer in the network. When you are finished, the router should begin broadcasting your Internet connection wirelessly.

Connect each computer to the wireless network. On each computer, find the wireless network's name that you assigned during the software installation. Connect to that network using the password that you created.

Share files over the network. To make files on 1 computer accessible to users on other computers, you must mark them as shared. In Windows, you can do this by placing the files in the "Shared Documents" folder or by right-clicking on each file and checking "Share this file" in the "Properties" menu. The process will differ slightly for other operating systems.


Connect to any devices in the network. To connect to devices such as printers and scanners, these devices will also need to be able to communicate wirelessly (this feature is not nearly as common on printers as on computers). To connect to a device, simply locate the device's icon on the network drive on each computer. Double-clicking on a printer's icon, for example, should install the printer and enable it for future use.

Practical number 4

Practical number 4

How to make a network cable

To create your own network cables you will first need the equipment we have listed below.

1.       Cat5, Cat5e, Cat6, or Cat7 cable - This cabling can be purchased in large spindles at stores that specialize in cabling. Cat5 cabling is the most commonly used cable used today for networks

2.      RJ-45 connectors - These connectors can be purchased at most electronic stores and computer stores and usually come in bulk packages. It is always a good idea to get more than you think you need.

3.      Crimping tool - These tools are often purchased at electronic stores such as radio shack. To create a network cable you need a crimper that is capable of crimping a RJ-45 cable (not just a RJ-11 cable, which looks similar to a RJ-45).

4.      Wire stripper or Knife - If you plan on making several network cables you should also consider getting a wire stripper cable of stripping Cat5, Cat6, or your cable of choice. If you do not plan on creating many network cables a knife will suffice. For simplicity and to prevent potential issues we recommend a wire stripper.
Once you have the necessary equipment needed to create your own network cables you need to determine the network cable you want to create. There are two major network cables: astraight through cable and a crossover cable. Below are some examples of what cable is used for each of the examples.

Straight through cable (T568A)

1.       Computer to hub, switch, router, or wall.

Crossover cable (T568A & T568B)

1.       Computer to Computer
2.      Network device to network device. For example, router to router.
Once you have determined the type of network cable strip the cable. We recommend stripping at least a half of an inch off of the cable to expose the inner wires. Don't be worried about stripping too much of the network cable jacket off since you can always cut the wires down more if needed later. After the network cable jacket has been removed separate the wires within the cable so they can be put into the RJ-45 connector.
The CAT5 twisted-pair cables consist of four twisted wires, each color coded; one a solid color and the other a stripped color. As seen below, most network cables consist of a green, blue, orange, and brown pair of cables.

There are two cable standards T568A and T568B, each twisted-pair must be broken apart to create the layout as shown above. If you want to create a straight through cable both ends of the cable should be identical and should match the T568A example shown above. If you want to create a crossover cable one end of the cable should match T568A and the other should match T568B.
Once you have separated the ends of the cable to match one of the above examples place the cables into the RJ-45 connector and then use the crimping tool to attach the connector. Do these steps for each side of the cable.

Once both ends of the cable have been completed connect the cable to make sure it is working.