There is a variety of data compression techniques, but only a few have been standardised. The CCIT (Comite Consultatif International Telephonique et Telegraphique), an organization that sets international communications standards. CCITT, now known as ITU (the parent organisation) has defined many important standards for data communications, including the following:
Group 3 and 4 – for sending fax documents over the Internet
V.21 - The standard for full-duplex communication at 300 baud in Japan and Europe
V.22 - The standard for half-duplex communication at 1,200 bps in Japan and Europe.
In addition there are file compression formats such as:
- ZIP files
- ARC files
ZIP files -A popular . Files that have been compressed with the ZIP format are called ZIP files and usually end with a.ZIP
ARC files - The ARC data compression format, created by Systems Enhancement Associates, is particularly popular among bulletin board systems (BBSs)
Data compression is also widely used in backup utilities, spreadsheet applications and database management systems, it’s also extremely useful for downloading huge MP3 (audio) MPEG, DivX, DVDRIP’s (movie files) from the Internet.
Task 3 – Achieving interconnectivity and interoperability in internetworking
Interconnectivity is the ability to connect different hardware and software from different vendors. As opposed to using hardware and software that is only compatible by the chosen propriety. For example back in the days when main frames ruled the world IBM had a market strategy which included making all their hardware compatible with specific hardware (mainly their own), however these days this is all changing.
In the oxford dictionary the word Interoperability simply means:
“Able to operate in conjunction”
However when we are talking about Interoperability within a computer network we are referring to the ability of two or more systems (computers, communication devices, networks, software, and other IT components) to interact with one another and exchange data.
A fundamental requirement of the new Uxbridge College’s C & T site computer system is that the existing sites must be able to communicate with each other and the outside world (through the Internet). Uxbridge College’s C & T site is aiming for a network with compatible with “state of the art technology”, and has many different applications. Uxbridge College’s new site will run on a variety of computers and other devices, and wish to connect to a wide variety of computers and devices. It is extremely important for them to not get tied down to one vendor. To avoid this the new site must have an open system!
An open system is a system that is able to work with as many different hardware and software vendors as possible. It is important in any computer network to choose systems that give you choice of hardware vendors and the widest variety of software applications. The great advantage of an open system (open architecture) is that anyone can design add-on products for it. By making an architecture public, however, a manufacturer allows others to copy its product. Linux (operating system), for example, is considered open architecture because its source code is available to the public for free. In contrast, DOS, Windows, and the Macintosh architecture and operating system have been predominantly closed.
Some of the benefits of an open system are:
- Competitive market based pricing
- A wide range of price/performance choices in software and hardware products
- Lower maintenance and training costs
- Continued product evolution and innovation
- Reduced probability of products becoming obsolete
On paper the benefits of open systems are undeniable giving the consumer more control and more efficient use of older equipment.
As computer systems evolve we enter the next phase of computer systems which a multi vendor network environment. This is mainly from consumer demand. This phase is merely at the birth stage of a major transition and there are still many companies that still prefer single source systems or systems that have more integrated support, guaranteed compatibility and responsive vendor relationships.
The key to efficient and reliable multi vendor network is choosing hardware components and software (operating systems, protocols, and applications) that are most interconnect able and interoperable on the market but not at the expensive of the networks requirements.
Task 4 – Application areas for the new site
The staff and students are going to need a whole range of applications ranging from Operating systems (applications to control the selected hardware) to office applications and lots of other various applications.
The overall system is going to need a Network Operating system (OS) and then each client is going to need a client OS.
Some of the more widely used Network Operating Systems include:
- Windows NT/XP
Some of the more widely used Client Operating Systems include:
- Windows 98 SE, Windows Millennium Edition (ME), Windows XP
As most application s are widely available for any of Microsoft’s (MS’s) client OS, it is an essential starting block for any computing students. Windows 98 is MS’s most reliable system to date. Windows ME and XP still have room for many improvements on the other hand XP will be the future. So any system that wishes to be cutting edge should be including XP.
Basic office applications are an essential starting point for any computing or IT students. Microsoft have made their office packages virtually industry standard. In other words these applications are essential packages for any small businesses. They include:
- Excel – for spreadsheets (numerical work)
- Access – for databases (the storage of data)
- Word - for word processing (creating word documents)
- PowerPoint – for creating visual presentations
Outlook – an email client (for sending receiving and manipulating mail)
Of course applications similar to these and even better than them can be obtained depending on the specialist area however these four applications come in a convenient bundle as MS Office 2000/XP. One of the main reasons for their popularity is they make excellent starting blocks for any student or person wishing to start a small business and is extremely easy to use.
Staff and students are more than likely going to be transferring files to and from other sources as well as use the internet. It is essential to any network to have an anti-virus protecting the network from certain viruses. Two market dominators include:
- Norton Anti-virus or Norton SystemWorks
- MCafree’s Anti-virus
Data compression software
Transporting files over a network is common place and one of the most important parts of transportation of data is the ability to compress and retrieve it. This is done by data compression software such as:
The students have been divided into the following general course categories (which can be sub divided at a later date):
- Computing (GNVQ’s, A/AS level, BTEC ND’s, and HND’s)
- Commerce (Beginners, CLAIT’s City and guilds)
- Engineering (GNVQ’s, A/AS level, BTEC ND’s, and HND’s)
- Art and design (GNVQ’s, A/AS level, BTEC ND’s, and HND’s)
For the Computing related subjects the following applications are recommended:
- Excel - Included in Office 2000/XP.
- Access - Included in Office 2000/XP.
- Word - Included in Office 2000/XP.
- PowerPoint - Include in office 2000/XP
- Borland C++ - a programming environment for the C++ programming language.
- Borland Delphi 5 - a programming environment for the Delphi programming language.
- Borland Java - a programming environment for the Java programming language.
- Borland Turbo Pascal - a programming environment for the Pascal programming language.
- MicroFocus COBOL - a programming environment for the Cobol programming language.
- Microsoft Visual basic 6 - a programming environment for the Pascal programming language
For the e-commerce related subjects the following applications are recommended:
- Mavis Beacon – Type tutor
- Macromedia Dreamweaver 5 – for creating web pages (HTML editor)
- Macromedia Fireworks 5 - for creating flash files (moving images)
- Adobe Acrobat 6 - for creating reading and editing with text images.
- Adobe Photoshop 6 - for creating and manipulating images (image editor)
For the engineering related subjects the following applications are recommended:
- AutoCAD – for Computer Aided Design (CAD).
- Croc Clips – for engineering designs.
- Electronic workbench – for designing electronic circuits.
- MV NSVQ 4000 series – a motor vehicle tool.
Art and Design
For the Art and Design related subjects the following applications are recommended:
- Quark Xpress – for desktop publishing
- Adobe Photoshop 6 and plug-ins – for creating and manipulating images.
What is bandwidth?
Bandwidth basically is the amount of data that can be transmitted in a fixed amount of time. For digital devices, the bandwidth is usually expressed in bits per second (bps) or bytes per second. Every machine on the internet is connected by a cable (usually; there are other ways to connect computers, but cables are the most common, and all connections have and use bandwidth in the same way). This cable has a capacity; it can carry a certain amount of information, sort of like a water pipe carries water. At either end of this cable, there is a computer which can send or receive data at a certain speed. The slowest of these three capacities is the bandwidth of the line; it's the fastest you can communicate between the ends. Think of the cable as a long tube with someone pouring water into it on one end, and someone draining it on the other. You can't take out more than was put in.
If 500 students are in one block it’s highly likely that there are going to be large numbers of students accessing the schools network and the Internet at the same time. Some applications (a few of them highlighted below) will place a particularly huge demand on the networks bandwidth especially:
Some of the applications that are likely to have a huge demand on bandwidth are:
- Web based search
- Email clients
- File transfers
- Chat rooms (web based discussion rooms)
- Audio/ Video conferencing
- On-line learning
- Voice over IP
Web based search
An example of applications that are hungry on bandwidth would be in a building with 500 students there are going to be a high numbers of students accessing the network for various tasks such as web based search, using Internet search engines. Each time a student requests information from his/her web browser they are placing a demand on the networks bandwidth.
Most staff and students will check their E-mail daily just as any body would check for post at home! Each time any of the students or staff uses the chosen E-mail client such as MS Outlook or Pegasus mail to send and receive mail this will place demand on the network.
Newsgroups can be a great resource for obtaining information on many different subjects. For example, if you would like to obtain information on train spotting, there is likely to be a newsgroup dedicated to it. Often participants in newsgroups are experts on the subject of discussion, but anyone can post questions and answer questions.
Many students daily will need to access files of theirs Download files, copy files and create new ones and save them to disk. Every time these files are transferred from the disk (usually large capacity disks accessed by servers) to the local memory of the client (the pc which the user is using) or downloaded from the Internet to the disks or client memory (or even to the client disk) the data is travelling along the networks media! These are some of the most common process and can place huge demands on the network especially when the files are audio or Image files.
Chat rooms (web based discussion rooms)
Chat rooms are live conversations online. They can be about all different subjects but the conversations are usually based around a common interest. Both staff and students may use them in pursuit of knowledge or join a discussion on a particular subject and as this requires the user to be on line during the conversation (discussion) this places a particularly high demand on the networks bandwidth.
Audio/ Video conferencing
This is a technology used to communicate in real time over networks using sound and video. It allows users to interact with others in remote locations without having to leave their homes or offices. Such a technology has already allowed many companies and individuals to save money which would otherwise be spent on long distance phone calls and expensive business trips
The basic network components are:
- Network adapter cards
- Switching hubs
Network media is the physical medium between one end node (point) to another. Network media comes in various shapes and sizes ranging from simple twisted pair cables to fibre optical glass/plastic and even the atmosphere with wireless communication now widely available.
Are still the most commonly used network media as they are they are a much more cost effective way of implementing and maintain network media.
Twisted pair cable (10BASE-T)
Twisted pair (also known as 10BASE-T) is ordinary telephone twisted pair wire. Twisted pair (10BASE-T) supports Ethernet's 10 Mps transmission speed hence “10” in 10BASE-T. The “BASE” refers to base band signaling and the “T” represents twisted pair just like the “F” for fiber optics in 10 BASE-F. There are many variations of twisted pair cable including:
- STP (Shielded Twisted Pair)
- UTP (Unshielded Twisted Pair)
- ScTP (Screened UTP)
Coaxial cable (10BASE-2)
Coaxial cable was invented in 1929 and first used commercially in 1941. Coaxial cable is called "coaxial" because it includes one physical channel that carries the signal surrounded (after a layer of insulation) by another physical channel. The outer channel serves as an earth. Many of these cables or pairs of coaxial tubes can be placed in a single outer casing and, with repeaters, can carry information for a great distance.
Fiber optics (10BASE-F)
Fiber optics sends digitized messages or information by light pulses along hair-thin glass fibers. Surrounding each fiber is a protective shell. This protective shell has a high index of refractance so that the light is internally reflected and travels the length of the fiber without escaping. Optical fiber cable can be made smaller and lighter than the conventional cooper or coaxial cable, yet they can carry much more information and is in general not subject to electromagnetic interference (EMI) and the need to retransmit signals. Most telephone company long-distance lines are now of optical fiber and it’s also commonly used as a back bone linking two or more sections of a network.. However the glass fiber requires more protection within an outer cable than copper. For this reason and because of costs many companies do not use it.
The two most popular types of network cab ling are twisted-pair (also known as 10BASE-T) and thin coax (also known as 10Base2). 10BaseT cabling looks like ordinary telephone wire, except that it has 8 wires inside instead of 4. Thin coax looks like the copper coaxial cabling that's often used to connect a VCR to a TV set.
Network Interface Cards (NICs)
A network computer is connected to the network cabling with a network interface card, (also known as a "nick", or network adapter). Some “Nicks” are installed inside of a computer: the PC is opened up and a network card is plugged directly into one of the computer's internal expansion slots. There are various network cards to support different speeds of network depending on the application. There are also special adapter cards for alternative ways to plug the adapter in. are considered Layer 2 devices because each individual NIC throughout the world carries a unique code, called a Media Access Control (MAC) address. This address is used to control data communication for the host on the network.
The purpose of a hub is to regenerate and retime network signals. This is done at the bit level. Hubs act in a very similar way to repeaters, which is why they are often referred to as multi-port repeaters. The difference is the number of cables that connect to the device. The main reason for using a hub instead of a repeater is to use the hub as a central connecting device usually connected with 10BaseT cabling. The reliability of the network is increased by allowing any single cable to fail without disrupting the entire network as opposed to using a repeater in a liner bus topology. Hubs are known as passive devices as they simply regenerate the any data sent to it as well as sending it out to all the devices it is connected to. This can considerably reduce the bandwidth of busy network as a result. Larger networks often use a thin coax backbone that connects a row of 10BaseT hubs together. Hubs are considered layer one (physical layer) devices as it only works with the physical signals.
The Switching hub, sometimes called a "Switch" is a more advanced unit over the basic hub. In a basic hub, all the computers connect to it and the speed of the network is defined by the slowest computer network card connected. If you have 10 100Mbps cards on the network and just on 10Mbps card, the system cannot run faster than that one 10Mbps card. There in comes the Switching hub. This hub treats each network card independently and in the matter of the 10 100Mbps network with the one 10Mbps network card, the Switching hub allows all of the faster connections to operate at the higher speed and still interact with the 10Mbps system. The switch also directs the data onto the right path (based on a table of MAC addresses) which makes it an intelligent device as opposed to passive.
In general, a server is a computer program that provides services to other computer programs in the same or other computers.
A bridge is a Layer 2 device designed to connect two LAN segments. The purpose of a bridge is to filter traffic on a LAN, to keep local traffic local, as well as allowing connectivity to other parts (segments) of the LAN for traffic that has been directed there. The bridge does this amazing fete by looking at the devices MAC address (local address). Every networking device has a unique MAC address on the NIC, the bridge keeps track of which MAC addresses are on each side of the bridge and makes its decisions based on this MAC address list.
The purpose of a router is to examine incoming packets (Layer 3 data), choose the best path for them through the network, and then switch them to the proper outgoing port. Routers are the most important traffic-regulating devices on large networks. They enable virtually any type of computer to communicate with any other computer anywhere in the world (routers are the backbone of the Internet) Working at Layer 3 allows the router to make decisions based on groups of network addresses (Classes) as opposed to individual Layer 2 MAC addresses. Routers can also connect different Layer 2 technologies, such as Ethernet, Token-ring, and FDDI.
Host devices are devices that connect directly to a network segment are referred to as hosts. These hosts include computers, both clients and servers, printers, scanners, and many other user devices. These devices provide the users with connection to the network, with which the users share, create, and obtain information.
Host devices are not part of any layer. They have a physical connection to the network media by having a network interface card (NIC) and the other OSI layers are performed in software inside the host. This means that they operate at all 7 layers of the OSI model. They perform the entire process of encapsulation and decapsulation to do their job of sending e-mails, printing reports, scanning pictures, or accessing databases.
Topology defines the structure of the network. There are two parts to the topology definition:
Physical topology - The actual layout of the wire (media)
Logical topology - The definition of how the media is accessed by the hosts.
Some of the more common types of physical topologies are:
- Star (and Extended Star)
Networks usually use one topology, but they can be a hybrid made up of two or more topologies to suit the individual needs of any system.
A Bus topology uses a single backbone segment (length of cable) that all the hosts connect to directly.
A Bus Topology is the simplest and most cost effective of the topologies. This means that the bus topology is the least expensive, but also the most susceptible to problems. If a problem with that cable should arise the whole network will be unable to communicate.
Advantages of bus topology:
Easy to implement and extend
Well suited for temporary networks that must be set up in a hurry
Typically the least cheapest topology to implement
Disadvantages of bus topology:
- Difficult to administer/troubleshoot
- Limited cable length and number of stations
- A cable break can disable the entire network; no redundancy
- Maintenance costs may be higher in the long run
- Performance degrades each time hosts are added
A star topology connects all cables to a central point of concentration. This point is usually a hub or switch.
If a computer, device malfunctions or a cable is cut, it only affects the computer that was attached to it. This eliminates the single point of failure problem associated with the bus topology (unless, of course, the hub itself goes down).
Advantages of a Star topology:
- Easy to add new stations
- Easy to monitor and troubleshoot
- Can accommodate different wiring
Disadvantages of a Star topology:
- Failure of hub cripples all attached stations
- More cable required than a bus topology
An extended Star topology uses the star topology to be created. It links individual stars together by linking the hubs/switches. This will extend the length and size of the network.
The Extended Star's main advantage over star topologies is that it extends the length your network can cover.
A hierarchical topology is created similar to an extended star but instead of linking the hubs/switches together, the system is linked to a computer that controls the traffic on the topology. The node at the highest point in the hierarchy usually controls the network. This topology is usually used to connect a large number of workstations within a single building or office.
Whilst this type of network is attractive due to its simplicity, it does have the potential to suffer significant bottleneck problems. With the uppermost node controlling all the traffic, there is not only the risk of bottlenecks, but also reliability problems if this node fails.
Advantages of a Hierarchal topology:
- If computer fails, computers can function independently
- Enables mirroring of cooperate structure
Disadvantages of a Hierarchal topology:
- Root is venerable
- If one of the hubs/concentrators (usually used to connect divisions together) goes down then there are problems with the whole division
Ring (Token Ring) Topology
In a ring topology all devices are connected to one another in the shape of a closed loop, so that each device is connected directly to two other devices, one on either side of it. Ring topologies are relatively expensive and difficult to install, but they offer high bandwidth and can span large distances.
*Note that while this topology functions logically as ring, it is physically wired as a star. The central connector is not called a hub but a Multistation Access Unit or MAU. (Or token but not to be confused with Media Adapter Unit, which is actually a transceiver.)
Advantages of ring topology:
- Growth of system has minimal impact on performance
- All stations have equal access
Disadvantages of ring topology:
- Most expensive topology
- Failure of one computer may impact others
A tree topology is a hybrid topology of a linear bus and star topologies. It consists of groups of star-configured workstations connected to a linear bus backbone cable.
Tree topologies allow for the expansion of an existing network, and enable schools to configure a network to meet their needs.
Advantages of Tree topology:
- Point-to-point wiring for individual segments.
- Supported by several hardware and software venders.
Disadvantages of Tree topology:
- Overall length of each segment is limited by the type of cabling used.
- If the backbone line breaks, the entire segment goes down.
- More difficult to configure and wire than other topologies.
A mesh topology is used when there can be absolutely no break in communications, for example the control systems of a nuclear power plant. Each host has its own connections to all other hosts (as shown in the image below). This also reflects the design of the Internet where there are multiple paths to one location.
Advantages of Mesh topology:
- Greater fault tolerance
- Computers Communicate With Each Other At Full Speed, Any time
- Eliminated Sharing Of Medium From The LAN.
Disadvantages of Mesh topology:
- Components are costly (as each host needs to be able to connect to al others)
- Very hard to administer and manager because of number of connections
The logical topology of a network is how the hosts communicate across the medium. The two most common types of logical topologies are:
Broadcast topology (also known as a bus topology), simply means that each host (computer, Printer or any other network device) sends its data to all other hosts on the network medium. There is no order and its first come first serve. If the data’s address matches that of the host, the host processes the data.
* Note that any physical topology can use a logical bus topology. This may be confusing, but if you think about how physical topologies are how the network is laid out and logical is just how the data moves across the medium
Advantages – Broadcast is useful feature in an e-mail system where the sender wishes to send out a multiple messages simultaneously
Disadvantages - If the cable is faulty all workstations lose network access
Token-ring topology (also known as sequential topology) the Token ring topology controls network access by passing an electronic token sequentially to each host. When a host receives the token it means that that host can send data on the network. If the host has no data to send, it passes the token to the next host and the process repeats itself.
*Note In theory every physical topology can use a logical token ring topology; however it’s completely unpractical for many of them.
Cost considerations for choosing a topology
The following factors should be considered when choosing a topology:
- Maintenance and troubleshooting
- Expected growth
- Existing network
An IP (Internet Protocol) address is a unique identifier for a node or host connection on an IP network. An IP address is a 32 bit binary number usually represented as 4 decimal values, each representing 8 bits, in the range 0 to 255 (known as octets) separated by decimal points. This is known as “doted decimal” notation. For example:
140 .179 .220 .200
Every IP address consists of two parts, one identifying the network and one identifying the node. The Class of the address and the subnet mask determine which part belongs to the network address and which part belongs to the node.
There are 5 different network classes, however we only use three of them as one is reserved for multicasting and the other for future use. You can determine which class a network address is in by examining the first four bits of the IP address. The addresses are classed as follows:
- Class A addresses begin with 0xxx, or 1 to 126 decimal
- Class B addresses begin with 10xx, or 128 to 191 decimal
- Class C addresses begin with 110x, or 192 to 223 decimal
*Note addresses beginning with 01111111, or 127 decimal, are reserved for loopback and for internal testing on a local machine. (You can test this by sending a ping to: 127.0.0.1, which points to yourself).
Below we can see how the class by default determines which part of the IP address belongs to the Network (N)and which part belongs to the node (n):
- Class A - NNNNNNNN.nnnnnnnn.nnnnnnnn.nnnnnnnn
- Class B - NNNNNNNN.NNNNNNNN.nnnnnnnn.nnnnnnnn
- Class C - NNNNNNNN.NNNNNNNN.NNNNNNNN.nnnnnnnn
Subnetting an IP Network can be done for a variety of reasons, including:
- For organisation purposes.
- If different physical media (such as Ethernet, FDDI, WAN, etc.) are being used in the same network.
- Preservation of address space.
- To control network traffic.
The main reason for a company to subnet is to control network traffic. As discussed in previous tasks network segments can be heavily inundated with data especially when the logical topology is broadcast (Sends the data to all nodes on the segment). All this data will seriously reduce the networks bandwidth (reducing productivity and possibly crippling the network). By applying a subnet mask to a network IP address Routers are able to identify the network and node part of the address and send data to a more appropriate part of the network and increase network productivity.
When applying a subnet mask the network bits are represented by the 1s in the mask, and the node bits are represented by the 0s. Or in other words to create subnets, we “borrow” bits from the host portion of the mask starting from the left most octet. For this example we will use our IP address of 220.127.116.11 with the default Class B subnet mask of:
18.104.22.168 Class B IP address
255.255.000.000 Default Subnet mask
*Note the network (N) portion of the subnet mask is not effected.
Default subnet masks:
- Class A - 255.0.0.0 - 11111111.00000000.00000000.00000000
- Class B - 255.255.0.0 - 11111111.11111111.00000000.00000000
- Class C - 255.255.255.0 - 11111111.11111111.11111111.00000000
Advantages of Subnetting
- Better traffic control
- Allows for growth (scalability)
- Better security
- Increase network performance
- Simplify network management
- Allows local network configuration
Disadvantages of Subnetting
Requires additional hardware (eg. Routers)
Decreases total amount of IP addresses available to you
Outside world will still see only one network address
Subnet design Considerations
The answers to the following questions will need to be taken into consideration as part of the subnet design:
- How many subnets will the College network need today?
- How many subnets will the College network need in the future?
- How many hosts will the college network need today?
- How many hosts will the college network need in the future?
Recommended Subnetting scheme
Assuming that Uxbridge College has been assigned a Class B IP address and at present there are ten major curriculum schools in the college, with a range of between 100 and 500students per school.
Estimated current number of students and expected number of students:
Total range of students today = 1000-5000 (Number of Students Today = nst)
Total expected range in the future = 5000-15000 (Growth factor = gf)
Maximum Possible total of students = 15000
Estimated current number of staff and expected number of staff:
So assuming that there is one member of staff for ten students then the staff to student ratio would be 1:10
Total range of staff today = 100-500
Total expected range in the future 500-1500
Maximum possible total of staff = 1500
Estimated number of subnets needed:
Assuming that there is the need for one subnet per school + growth = 20-30 subnets needed Total Subnets = 30
Estimated number of hosts needed:
Estimated number of hosts needed = Maximum Possible total of students + Maximum possible total of staff
= 15000 + 1500 = 16500
Total hosts =16500
Total of hosts needed per subnet = Total hosts
550 hosts per Subnet = 550:1
Uxbridge College Subnet mask
22.214.171.124 Class B address
255.255.248.0 Subnet mask
As it’s a class B address the first two octets (bytes) will represent the network protion. This means that the in first two octets (The very left most as this is where the Most Significant Bit-MSB lies) will all be set to 1’s. The third octet will be represented by the following bit pattern:
Fourth Octet will all be set to 0’s
In binary the complete mask will look like: 11111111.11111111.11111000.00000000
Formula to work out number of Subnets is:
Subnets are 2 to the power of “x”-2 where “x” is the number of bits borrowed from host portion of a subnet mask
Formula to work out number of hosts per Subnet is:
Number of hosts per Subnet is 2 to the power of “x”-2 where “x” is the number of host bits minus the number of borrowed bits.
*Note the number of host bits will vary depending on the class of address. For example:
Class A = 24 host bits
Class B = 16 host bits
Class C = 8 host bits
Number of Subnets for Uxbridge College
Number of Subnets = 2*2*2*2*2-2 = 30 Subnets
Number of hosts per Subnet for Uxbridge College
Number of hosts per Subnet = 2*2*2*2*2*2*2*2*2*2*2-2 = 2046 hosts per subnet
Advantages and disadvantages of using networks within the college
Networking is one of the most important but also most dynamically changing areas in modern computer applications. Having a fully functional network allows:
- File sharing
- Printer sharing
- Simultaneous Internet access
- One centralised data store
- Saving and retrieving files from remote locations
- Communicating with colleges across the building or across the continent
This allows files on one computer (word processor documents, spreadsheets, photographs etc.) to be accessed on another computer without having to copy it to a diskette first.
This lets you print from one computer directly to the printer attached to a different computer. Perhaps you have one PC with a photo printer on it and another PC with a laser printer connected to it. Printer sharing allows either PC to print to either printer.
*Simultaneous Internet access
Considering Uxbridge College will have the need for many people (students/staff) to access the Internet simultaneously it would be an expensive as well as impossible to manage every user having independent Internet access. By implementing a functional and efficient network many researchers can access vast collections of information at the same time using a lot of the same hardware. For example to have a secure and safe Internet access the College would require some sort of firewall. This is a costly piece of hardware or software, however if the cost is spread over the amount of people able to access the Internet it is much more justifiable.
*One centralised data store
Large hard disks (or data server) provide one allocated area for storing all documents (word processing, spreadsheets, database, audio and Image documents etc). This in turn enables backing up data to be done more easily as well as efficiently.
*Saving and retrieving files from remote locations
Students or staff may have worked on a project or task at home or college but may be to large to store on transportable disks, however hey could use the Internet to access the college network (internal Internet-Intranet) either by sending it to a mail server then retrieving when needed or by the network administrators setting up remote access privileges to staff or students.
*Communicating with colleges across the building or across the continent
A staff member or student may be stuck for inspiration or may simply need some advice from another member of staff or a fellow student. His is not always convenient for both parties not to mention time consuming. One of the features of a computer network is the ability to send messages to any persons (providing you know their log in names) either individually or the same message to a selected number of people or for management purposes a broadcast message can be sent to all users in a particular school or the entire college network.
Benefits of installation of network at new site
Accessing resources, printing to multiple printers, saving and retrieving files from remote locations, and communicating with a colleague across the building or across the continent are the advantages of a computer network that helps users get their work done easier, and gives students the ability to increase their learning. As you can see the advantages of having a computer network at Uxbridge College out weighs the disadvantages.
Uxbridge College’s management staff can monitor on a daily basis any useful statistics such as overall achievments, profit margins, payments and other information. Without a computer network linking the massive College, a significant amount of time would be required to assemble this kind of information. Uxbridge College’s network would allow the company to identify schools that are struggling and meet them with appropriate responses.
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