Network Topologies 4000 words

 

 

 

 

Networks Assignment

 

Student Name:

Course:

Submitted To:

Date:

Task 1:

Setting up a small peer-to-peer network

I set up a small, low-bandwidth peer-to-peer network between two computers using a direct cable connection, via a crossover cable.

 

Equipment Required

  • 2 desktop computers with network cards installed (10/100 Ethernet network card)
  • Crossover cable

 

Steps

Step 1: Connect the two computers using the crossover cable. The two ends of the cable will be connected to the network ports (found at the back side of the CPU) of both computers.

After the physical connection is made between the two computers, the networks will be set on each machine. I did this simply by following the steps presented in the Network Setup Wizard. The steps of the process are:

Step 2: On one computer, click Start – Programs – Accessories – Communications – Network Setup Wizard. This computer was running Microsoft Windows XP.

Step 3: The Network Setup Wizard page will appear. Click Next. Click Next again when the second page appears.

Step 4: In the third page which asks, “Do you want to use the shared connection?” select “No, let me choose another way to connect to the Internet.” Then click Next.

Step 5: In the “Select a connection method” page, click “Other” and then Next. Since at this point the network is being set up, there is no need to configure the Internet, which can be done at a later stage.

Step 6: In the fifth page, “Other Internet connection methods…” select “This computer belongs to a network that does not have an Internet connection” and click Next.

Step 7: In the next page (“Give this computer a description and name.”) type a computer description and the name of the computer. I named this computer FIRST. Click Next.

Step 8: In the “Name your network” page, give the workgroup a name. I named it HND-Network2010. Click Next.

Step 9: In the next “File and printer sharing page” I selected the first radio button (“turn on file and printer sharing). Click Next.

Step 10: In the next page of the wizard (“Ready to apply network settings”) click Next after reading the contents of the page.

Step 11: The Network Wizard will initiate creating all those files required in setting up the network, based on the selections made. Once done, a new page will appear (“You’re almost done…”). I selected the first option (“Create a Network Setup Disk”) and used a flash drive for the process. Click Next.

Step 12: The next page (“Select a disk drive”) will present the portable mediums available, such as “Removable Disk”, “3.5 Floppy” etc. I selected the drive for the flash drive (after inserting it in the USB port of the computer). Click Next.

Step 13: The next page will ask whether or not the disk should be formatted. Click Next after allowing the disk to format. This will copy all network files in the flash drive.

Step 14: Click Next in the next page (“To run the wizard with the Network Setup Disk…”).

Step 15: The last page will read “Completing the Network Setup Wizard.” Click Finish. A message box will appear asking whether or not you wish to restart your computer. Choose Yes.

 

This will set up the network on the first computer. The network can be setup on the second computer by either following the steps in the network wizard or using the setup disk (created on the flash drive).

I named this computer “SECOND” and the workgroup “HND-Network2010.” At this stage the network wizard will search if that workgroup name is already being used in the network. If yes, it will allow this computer to join the existing HND-Network2010 network.

 

Installing a Windows Operating System

Windows XP can be installed following the below steps:

Step 1: Insert XP CD in the CD ROM and restart the computer

Step 2: Press any key to allow the computer to boot from the CD. This will begin the Windows setup process. Press the ENTER key when prompted.

Step 3: Press F8 to consent with the Windows XP Licensing Agreement page which appears

Step 4: Select where to install Windows XP on the hard disk drive. This will also delete all existing data from the drive.

Step 5: Press ENTER to choose unpartitioned space. Press ENTER a second time to choose “Format the partition using the BTFS file system.” This will allow all setup files to be formatted and copied. The system will then restart and continue with the setup and installation process.

Step 6: Enter your company name and your name in the Personalize your Software Page which will then appear. Click next and enter the product key in the Product Key page, which will appear next. The product key will be listed on the Windows CD case. Click next.

Step 7: Enter an appropriate computer name, which will identify the computer and a password. Reconfirm the password by entering it again.

Step 8:  Set the time and date for the computer’s clock. Then click next.

Step 9: Click next on the Computer Domain page. The computer will restart by itself if it has been configured.

Step 10: When the display settings box appears, click OK. Click OK again when the Monitor Settings box appears. Click next when the “Welcome to Microsoft Windows” page appears.

Step 11: Click Next after turning on Automatic Updates. Windows will check if the computer is connected to the Internet. Press Yes if Internet is connected, then click Next.

Step 12: Fill out the Collecting Registration Information form and click Next.

Step 13: Insert the names of all the users who will be using the computer in the “Who Will Use this Computer?” page. Click Next.

Step 14: On the “Thank You” page, click “Finish.”

Step 15: Select an appropriate theme. The Installation is now complete.

 

On the FIRST computer:

On the desktop, right-click and make new folder by clicking on “Folder.” A new folder icon will appear on the desktop. Rename this folder to HND-Network2010_yourname. Right-click on this folder and click on “Sharing.” A window will appear (“SHARED Properties”). Select the third tab “Sharing” from that SHARED Properties window. Click on the second radio button “Share this folder.” This will create a shared fold

Repeat the above for creating a shared folder in the SECOND computer.

 

Rights and Responsibilities of Network Manager

The network manager or network administrator is the individual responsible for ensuring that a network functions effectively. Other essential roles and responsibilities of a network manager include:

  • Planning and designing a network: Network managers plan and design networks on the basis of the needs of an organization.
  • Setting up a network: Network managers set up networks by installing its hardware components and configuring their routers, hosts, databases, files and network servers.
  • Maintaining a network: Network managers maintain networks by administering its security; administering services such as name services, NFS services and e-mail services; troubleshoot problems and errors
  • Expanding or reducing the size of the network: Network managers expand networks by adding new hosts/machines and network devices.
  • Setting up user access: Network managers are responsible in providing user access. They are used to define which programs/files users can access and which they are prohibited from.

 

Rights and Responsibilities of Network Users

Rights

Privacy: All users have the right to keep their private communication private. However, this right is overridden if the rights of other users or the integrity of the network is violated.

Back up files: Users can back up directories and files on a computer system. However due to security reasons, network administrators specify which users are granted this facility and who are deprived of it.

Change time: Users who have been granted the “change the system time” right can change the time on their computer systems.

Log on locally: Users have the right to log on locally/interactively by pressing Control + Alt + Delete. This is done when users are sitting right in front of a computer system.

Network access: by default, all users of a network are allowed access to the resources present on their particular workstations.

Shut down: Users who are granted a shut-down right can shut down their systems.

Ownership: Users who are the owners of particular resources, such as folders or files, have the right to change the access of control or permissions on that particular resource. User-owners can grant permission to some users to access their resources and deny others from access.

Add workstations to the same domain: Users can add workstations or computer accounts on a domain.

Change memory quotas: Users can change the memory that is allocated to a particular process.

Other user rights include shutting down a Windows server computer; restoring directories and files; synchronizing data on a particular directory; monitor processes through tools, including Alerts utility and Performance logs; perform maintenance tasks such as remote defragmentation; modify firmware environment variables; manage the security log; and unload and load device drivers.

Responsibilities

Users must only access all that information/data and services they have been specifically provided access to, or allowed to use. Access to all resources and data to which users have not been specifically authorized is prohibited by default.

Users are responsible for ensuring that they keep the equipment in their use secure. Users are to ensure that they do not leave active sessions, data carriers and equipment unattended.

Users are accountable in ensuring that all resources and services they are authorized to use be used responsibly.

Task 2:

 

Discuss the role of networks within different organisations and the resource implication of networks.

 

Networks are now an essential component of most medium and large-scale organisation’s. They offer an effective way for organizational components to communicate with each other. Specific reasons networks are used in organisations include:

 

  • E-Commerce

Organisations use the Internet, a wide-area-network (WAN) to conduct e-commerce, or provide/offer services and goods to customers. Other types of networks are also used to conduct electronic commerce, such as taking orders online, providing online catalogues, and others.

  • Resource Sharing

Organisations use networks to share resources between its users, both internal employees and managers, and external suppliers and customers (Rustin 1972).

Organizations also use networks to share hardware and software resources, such as printers, scanners and CD-ROMs.

  • Communication

Organizations use networks as a tool to facilitate communication between their stakeholders. Communication is underway using e-mail, teleconferencing, videoconferencing and other methods.

  • Storage

Most organizational networks have a central dedicated server that functions as a storage repository. This computer holds all data, records and information pertaining to that organization and provides access to authorized users when required.

  • Cost Efficiency

Networks are a cost efficient way to cut down on software costs. Stand-alone programs and program packages can cost hundreds of dollars per unit, and cause a significant dent in an organisations budget. Networks solve this problem by allowing an administrator to install a software on the server computer (or any other machine) and provide access to all other network machines.

 

Resource Implications of networks

 

Networks allow their users to share hardware and software resources. Resource sharing allows remote users to access vital data and devices.

Typical resources that are shared include CD burners, scanners, printers, company records, accounts receivables, tax information, and others.

 

Discuss the different distributed computing approaches of peer-to-peer and client-server networks

In a peer-to-peer network, all nodes are equal, with each one called a peer. Without a trusted, central authority, each peer requests and addresses the requests of other peers.

Distributed computing is a type of computer processing in which parts of the same program run on two or more devices that are communicating over a network. According to Steven Karris in the book “Networks: Design and Management,” separate computers, which are linked by communication links, process information. Distributed processing is of two types: true distributed processing and plain distributed processing. In true distributed processing there are different computers to perform different tasks in such a way that their work is combined and forms part of a larger goal. This type of processing requires software and hardware components to exchange information and share resources freely. Plain distributed processing allows computers to share processing load.

Distributed systems allow for collaborative work or exchange of information; resource sharing (backup storage, printer, disk unit, applications, services and information media); cost reduction; and increased performance.

Distributed Computing Approaches of Peer-to-Peer Networks

In peer-to-peer networks, the workload or processing tasks are distributed between the peers, who each have equal privileges.

 

 

Explain the functions of client and server computers on a network and give at least one example of the interactions between a client and server computer

 

A client-server network is a group of two or more connected “client” and “server” workstations. Clients are all those computers that connect to the network and access its resources and/or request services. Typical services requested include running a software, saving data, querying a database and the like.

A server is a centralized system that is used to address and manage client requests.

 

Functions of Server Computers

  • Server computers receive client requests
  • Process client requests
  • Generate results

 Functions of Client Computers

  • Client computers are responsible for:
  • Handling user interfaces
  • Translating a user request into its relevant server-understandable protocol
  • Sending user request to be processed by the server
  • Waiting for the server’s response
  • Translating the server’s response into a user-understandable result
  • Presenting the results of the server response to the user.

 

Example of Interaction

An example of a client-server interaction is the name server/name resolver relationship in Domain Name System (DNS).

 

Describe the advantages of client-server approaches particularly over centralized services.

 

Earlier computer networks were primarily based on centralized models. Centralized computing systems typically incorporated specialized applications written for specific architecture and system. Centralized services were typically provided by large, mainframe computers that had multiple terminals connected to them and provided them requested services (Subramanian and Goodman 2005)

In contrast, client-server approaches include a number of complex servers and simple clients. The client-server model offers various advantages over centralized computing models in terms of scalability, flexibility and usability (Siegel and Shim 2003). Some advantages are listed below:

  • Scalability: Client-server computing allows for easy network expansion and reduction.
  • Less Vulnerability: Client-server computing is less vulnerable than centralized services/architectures. A fault in one server can be appropriately be managed by a backup server, or a mirror server; and a fault in any one client does not affect the performance of the rest of the network.
  • Processing Load is Evenly Distributed: In a client-server architecture, processing load is distributed over the network instead of being concentrated.
  • Economical: Hardware and software components are more economical and simple.
  • Efficient: Client-server models are more efficient than centralized models, since tasks are appropriately divided between clients and servers.
  • Flexible: Client-server models can store data in different ways; either distributed across several different servers or stored on one server.

 

 

Task 3:

Network Topologies

 

Network topologies are the way in which a network is organized and its components are physically connected. A topology defines the physical layout or the shape of the network from a bird’s eye view.

There are many different types of network topologies, including:

 

 

Star Topology

 

 

Star topology is the most common layout in Local Area Networks (LANs) due to its ease of installation and greater fault tolerance. In a star layout, all network devices are connected to a central hub or switch either through cables or wirelessly.

A star topology offers numerous benefits over a bus topology, making it more frequently used although it requires extensive cabling and physical media. One of its most beneficial features is that each network segment or computer is connected individually to the central device. If a particular cable fails or another fault is generated in a machine, it will not affect the rest of the network. This feature makes the star topology more fault tolerant than the bus topology and allows errors to be easily detected. Another main advantage of the star topology is its scalability – nodes can be added and removed from the network simply, by merely adding or removing its connection from the central hub/switch.

Star networks are typically implemented using UTP, or unshielded twisted pair cable.

Advantages

  • Easy to wire and install
  • No disruptions to the network and other devices when removing or adding nodes
  • Easy to detect and isolate faults
  • Easy to add more workstations and remove them
  • Centralized management due to a hub

Disadvantages

  • More cabling required, which amounts to greater installation cost
  • Greater maintenance costs
  • A fault in the central connector or hub affects the functioning of all connected nodes
  • Expensive as compared to most other topologies due to the cost of the hub.

 

 

Bus Topology

The bus topology is the most basic of the network topologies. It consists of two distinct ends, with each device connected directly to the same unbroken cable that runs through the entire length of the network.

The “bus” cable, also called the trunk, forms the backbone, to which all nodes are connected. This is typically a coaxial cable.

Both ends of the trunk have terminators, which are devices used to absorb the signal to prevent it from reflecting back on to the bus.

 

 

In a bus topology, a signal is sent to all nodes. Each computer on the network checks the data frame on the signal (the address of the data) as it passes through the network. If the address matches the address of the computer, the computer accepts the signal; if the address does not match the computer, it ignores the signal and it travels down the bus.

A bus network allows only one device to “talk” at one time. This type of network typically uses CSMA/CD, a media access method, which handles collisions of data when two different signals are on the same line at the same time.

  • Regular Bus

In a regular bus, each workstation is attached using a drop cable to the bus cable.

  • Local Bus

In a local bus, each workstation is attached using a “T” connector to the bus cable. Peer-to-peer networks are typically formed as local buses.

 

Advantages

  • Easy to extend and implement
  • Fast setup
  • Suitable for temporary networks that need to be arranged quickly
  • Cheaper than other network topologies
  • A failure in any one node on the network does not affect the functioning of the network

 

Disadvantages

  • Difficult to troubleshoot and administer
  • Limited number of workstations and cable length
  • A fault or break in the cable can affect the entire network
  • More expensive to maintain
  • Performance is inversely proportional to the number of network nodes.

 

Ring Topology

In a ring topology, each device on the network is directly connected to its two adjacent neighbouring devices on the same network. The physical layout of the ring topology represents a link, with data flowing through the network (from computer to computer) till it reaches back to the source.

 

A ring network is easy to install and reconfigure. Typically, in a ring topology, a signal is circulating continuously, and a node that does not receive a signal for a considerable amount of time generates a fault. This makes fault isolation and detection relatively easy in a ring topology.

However, the failure of any one node on the network causes the entire network to collapse.

Another disadvantage of a ring topology is that traffic can flow in only one direction.

Ring topology is not effective when the number of computers or nodes is high.

 

Advantages of Ring Topology

  • Data can travel at greater speed
  • No collision of data
  • No terminators required
  • Easy to identify faults in cable and devices

Disadvantages

  • More cabling required as compare to bus
  • Adding devices to the network suspends the use of the network for all other devices

 

Hybrid Topology

Hybrid topology, as its name indicates, is a type of network that uses two or more different types of topologies.

 

Tree Topology

Tree topology is a derivation of the star topology. It is basically a hierarchy of multiple hubs, and represents the many branches of a tree. In a tree topology, all nodes are connected to a hub; however, only a few nodes are connected to the central hub directly.

The central hub, also called an active hub, in the tree topology typically consists of a repeater, which is a device that accepts incoming bits and converts them into signals representing 1 and 0, as required. This allows data to be transmitted over longer distances.

All other hubs besides the central, active hub, are called passive hubs.

 

Network Devices

Hub

A hub is a network device that functions to connect two parts, or segments, of a network. In a star topology, for instance, each device on the network si connected directly to its central hub.

LAN Card

A LAN card, also called a NIC, or network interface card, is used to connect different workstations on a network. LAN cards are typically installed on PCI ports within computers. Each LAN card has a unique Media Control Access (MAC) address, which consists of two parts, namely the manufacturer ID and the card ID.

Switch

A network switch functions similar to a hub. The only difference is that unlike a hub, a switch does not broadcast signals or data to all network devices.

Computers on a network are connected directly through Ethernet cables to the switch.

Gateway

Gateway refers to a software or hardware that bridges two networks. It can be thought of as a networks entrance point. Gateways are typically used to connect local area networks with the Internet.

Repeater

Repeaters are network devices that repeat the transmission, or retransmit, weak signals within a network. They remove all noise from incoming signals and then transmit it onward towards their destination. Large networks typically consist of multiple repeaters, which are used to amplify signals.

Router

A router is a network device that connects two or more different networks. Routers can be used to connect a local area network with another local area network; a local area network with a wide area network; or two wide area networks.

Bridge

A bridge is a network device that connects two parts of a local area network which are using the same protocol. A bridge can be thought of as a router which sends data without analyzing it.

Modem

A modem is a network device that performs two primary functions: modulation and demodulation, or conversion of analog to digital signals and digital to analog.

Cable

There are many types of cables used to connect components of a network. These include UTP (unshielded twisted pair cables), STP (shielded twisted pair cables), coaxial cables and fiber optic cables.

  • UTP

UTP cables are classified into six different types by the Electronic Industry Association (EIA). These types include:

o   Category 1

Speed: 1 Mbps

Use: Telephone wire (voice only communication)

 

o   Category 2

Speed: 4 Mbps

Use: Telephone & local talk

 

 

o   Category 3

Speed: 16 Mbps

Use: 10BaseT Ethernet

 

o   Category 4

Speed: 20 Mbps

Use: Token Ring

 

o   Category 5

Speed: 100 Mbps (two pair)

Use: 100BaseT Ethernet

 

Speed: 1000 Mbps (four pair)

Use: Gigabit Ethernet

 

o   Category 5e

Speed: 1000 Mbps

Use: Gigabit Ethernet

 

o   Category 6

Speed: 10,000 Mbps

Use: Gigabit Ethernet

 

  • STP

 

  • Coaxial Cable

A coax cable has an outer insulating layer surrounding an inner conductor.

Types: RG-6/U, RG-8/U, RG-62/U, RG-180B/U, RG-213/U, H500, LMR-195

 

  • Fiber Optic Cable

Types: multimode and single mode

 

 

Role of Software and Hardware in Networks

 

Software

The physical connections between network devices is only one component of a network. Devices on a network must communicate by using appropriate software, that allows them to send and receive data. Software Various types of software support the effective functioning of networks. There are different types of network software, each type performing different functions or roles within the network. These include:

  • Communication Software: To facilitate video conferencing, teleconferencing, instant messaging and email
  • Security Software: Data-access management applications, firewalls, spam filtering and antivirus
  • Productivity Tools: Word processors and Spreadsheets
  • Troubleshooting and Monitoring Software: Troubleshooting software, such as network analyzers, performance bottlenecks can be mitigated to decrease maintenance costs. These software secure networks by updating appropriate security tools, security patches and firewalls. Troubleshooting software continuously scans networks to detect and correct errors.
  • NOS (Network Operating Systems): NOS are usually installed on server computers and are used to control and manage the resources of the network. Examples include Microsoft Windows Server, UNIX, Novell and Macintosh OSX
  • Protocols: Protocols are rules that must be obeyed by all network devices before communication can be made underway. Protocols govern the type of interactions between computers or other network devices. Some protocols include DNS, DHCP and FTP.

Hardware

Various network hardware devices are used to set up a physical network. Hardware is used to form the primary network infrastructure or topology. The primary role of network hardware is to facilitate the transfer of data between different network devices.

 

Factors Influencing Choice of Networks

Several different factors must be taken into consideration before selecting an appropriate network. These include (Tanenbaum 1996):

 

  • Cost

Most networks operate within defined budgets. Budgetary constraints can effectively determine which network to select for a particular site. The most inexpensive network to set up is a bus network, since it does not require the involvement of concentrators or hubs.

 

  • Length or Size of Network

The size of the network or the number of devices that will eventually constitute the network determines which type of network to choose. Bus topologies, for instance, are most effective for small networks.

  • Future Growth

Another important factor in selecting the network type is whether or not that network is expected to grow in the future. For instance, a star topology is easy to expand with the addition of other concentrators, but it requires additional cost. The expansion of a bus topology, on the other hand, is less expensive, but bus topologies are limited in size.

  • Communication Distance: How must distance must a signal traverse before reaching its destination? Communicating distances, ideally, must be as short as possible to facilitate effective communication.
  • Troubleshooting and Ease of Installation

 

Suitable Network

The most suitable network for the Oast House Group is the client/server model of star topology, for the below reasons:

  • Centralized repository of data which maintains information of all clients and employees
  • Ease of adding and removing devices
  • Ease of maintenance and fault tolerance
  • Provision of a centralized database for sales and inventory information

 

 

 

 

References

 

Balter, Dan, and Derek Melber. MCSE Windows XP Professional . Scottsdale, Ariz.: Coriolis, 2002. Print.

Bidgoli, Hossein. Handbook of Computer Networks . Hoboken, N.J. : John Wiley & Sons, Inc., 2008. Print.

Comer, Douglas. Computer Networks and Internets . 2nd ed. Upper Saddle River, N.J.: Prentice Hall, 1999. Print.

Rustin, Randall. Computer Networks . Englewood cliffs, N.J.: Prentice-Hall, 1972. Print.

Siegel, Joel G., and Jae K. Shim. The Manager’s Handbook of Client/Server Computing in Business and Finance . Mason, Ohio: Thomson/South-Western, 2003. Print.

Subramanian, Ramesh, and Brian D. Goodman. Peer to Peer Computing the Evolution of a Disruptive Technology. Hershey, PA: Idea Group Pub., 2005. Print.

Tanenbaum, Andrew S.. Computer Networks . 3rd ed. Upper Saddle River, N.J.: Prentice Hall PTR, 1996. Print.