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  • 1. Information & Guidelines on Networking in Schools Version 1.0 Issued by National Centre for Technology in Education (NCTE) Date: Dec’ 1st 2003 NCTE Guidelines for Schools Networking 1
  • 2. 1.0 Introduction These guidelines should be read in the context of the letter of 8th December 2003, from the Department of Education and Science, (DES) and in association with the NCTE Advice and Planning Pack issued to schools in 2002. An extract from the DES letter of Dec 8th reads as follows: “There are several practical advantages to having a school network, including shared access to files, software and other resources, centralised administration systems and shared access to the internet, printers, scanners and other devices. Accordingly, it is recommended that school authorities should give priority, where relevant, to achieving improved levels of networking of computers within the school and that grants should be primarily used towards this goal. For more information on networking, please consult with the ICT Advisor in your area or refer to the networking section of the NCTE website at ” The guidelines are not meant to be a complete guide to all aspects of networking but rather as a support to schools in planning the next stage of the local network in their school. Other related objectives of this document are: • to assist schools in understanding the benefits of networking • to help schools place in context the current stage of the development of their local school network • to provide standard networking ‘models’ and best practice to schools which will assist schools in the next stage of planning their network. This document includes information under the following main headings: • Networking Models – Towards a networked school • Example network configurations • Costs of Networking • Cabling Guidelines and recommendations: • Basics of school Networking • Types of Networks • Advantages of Networking • Some relevant terms. Having reviewed the document schools requiring further advice should consult with their regional ICT Advisor whose contact details may be found on the NCTE website at: During 2004, and in addition to this document further information/resources relating to networking will be added to the NCTE website at For latest NCTE information schools are advised to consult this section of the website when they are undertaking an upgrade of their local school network. Note: School Administration Network and General school network This document focuses primarily on the general school network rather than the specific requirements of th administration network within a school. The two areas are of course related and there are opportunities to apply a more integrated approach such as combining internet access, setting up different workgroups, or virtual local area networks etc. This area is not covered in the document and will be covered either as an update or in a separate Guideline in 2004. NCTE Guidelines for Schools Networking 2
  • 3. 1.1. Networking Models: Towards a Networked School This model (fig 1) shows a simplified diagram of a networked school indicating the various types of networking models used. These include computer rooms, networked classrooms, and networked specialist rooms for specific subjects. Mobile networked solutions are shown in the Resource room, the General Purpose room and in Building 2. Note: To improve readability, only the network points are shown here, rather than cabling itself. Main School Building School Principals Admin Office Technology Office Room Staff Room Post Primary Resource Science Room Standard Labs Classroom Post Primary Classrooms Standard General Purpose Room Standard Classroom Standard Standard Classroom Classroom ICT Server & Store Equipment Room Room Standard Classroom Standard Classroom Standard Specialist Classroom Room Post Primary Computer room Standard with 15-30 computers Classroom Specialist Room Wireless link to Post Building 2 Primary Building 2 Building 3 Temporary Pre-Fab - Wireless Network Fig 1: Representation of a Whole School Network Model NCTE Guidelines for Schools Networking 3
  • 4. Junior Infants Senior Infants 1st Class 2nd Class Resource room Principal/Office # of computers # of computers # of computers # of computers # of computers Staffroom # of computers 3rd Class # of computers File & Print Server Access to: Internet content & learning resources, 4th Class Scoilnet etc # of computers Email communication Cache, Proxy, Server 5th Class # of computers School ‘Local Area Network’ (LAN) Modem or Router / Firewall 6th Class # of computers Fig 2: Typical Network Model for a Primary or Special school. Figure 2 shows a network model for a Primary or Special school. This includes connectivity to all classrooms to a local area network (LAN). The network connects to a File and Print Server. Internet access is handled via a modem or router, while Web Caching and Proxy service are all handled via a dedicated server. standard classroom computer room Staff room Principal/Office Library # of computers # of computers # of computers # of computers # of computers science lab # of computers File & Print Server Access to: Internet content & learning resources, technology lab Scoilnet etc # of computers Email communication Cache/Proxy, Server resource room # of computers School ‘Local Area Network’ (LAN) Modem or Router / Firewall specialist room # of computers Fig 3: Typical Network Model for a Post Primary school. Figure 3 shows a model for a Post Primary school. This includes connectivity to all classrooms back to a central network. The network connects to a File and Print Server. Internet access is handled via a modem or router, while Web Caching and Proxy service are all handled via a dedicated server. NCTE Guidelines for Schools Networking 4
  • 5. File & Print Server Printer Multimedia or Scanner CD Server Access to: Internet content & learning resources, Scoilnet etc Email communication Cache/Proxy, Server Main Servers & Internet Access Modem or Router/Firewall To Network Fig 4: Server Functionality Model Server Functionality (Fig 4) The network connects to a file and print server. The ‘file server’ stores common files, while the ‘print server’ manages the different requests for printing. A multimedia or CD server is used to store and distribute Multimedia - sound, video, text learning applications. Internet access is handled via a modem or router, while while Web Caching and Proxy service are all handled via a dedicated server. Example network configurations: Models for Networking First let’s review some simple models where no networking exits and where computers are used in standalone or ad-hoc mode. The following represent some simple models representing classrooms. Model 1a: One computer in a classroom with its own private printer. It is recommended that schools with computers in this situation would network the classrooms in question as shown. Networking will more effectively make use of commonly shared resources such as file servers and school printers, internet, email etc. When a mobile PC or PC with projector is require in a room the network points are already present. In this scenario, there could be a single LAN-connected point for the teacher and an additional LAN connection to allow for a portable switch. Model 1a Fig 5a: From single PC to networked LAN Points NCTE Guidelines for Schools Networking 5
  • 6. Model 1b: This scenario is similar to Model 1a, but where other equipment such as printers, scanners are used in ad-hoc and inefficient configuration. It is recommended that schools with computers in this situation would network the relevant classrooms. Networking will more effectively make use of commonly shared resources such as scanners, printers, internet, email etc. In this scenario there may be a single LAN- connected point for the teacher and some LAN connection points in the room to allow students access to the school LAN. The connection points may be situated as required around the room depending on the specific purpose that the room is used for. Model 1b: Fig 5b: Networking other commonly used equipment Networked Computer Room Model 1c: A non networked computer room or resource area with an ad-hoc and inefficient use of printers, scanners etc. A networked computer room is essential so that all PCs can access common resources such as file servers, printers, the internet, email etc. This scenario represents a school computer room which can be timetabled for classes, and with each computer networked to the LAN. There may be a single LAN- connected presentation point for the teacher and LAN-connected computers throughout the classroom for pupils. Traditionally, ICT in Irish secondary schools has been concentrated in dedicated computer rooms, which is attractive as an entire class can receive hands-on computer use. Primary schools usually have more varied deployment. Model 1c: Fig 5c: Networked computer lab. NCTE Guidelines for Schools Networking 6
  • 7. Media Bays (Ref Fig 6a) Mobile Media bays, or data suites are clusters of about four desktop computers, and often including a scanner and printer which can be moved (usually on a trolley) to particular areas or classroom in the school as required. Though self-sufficient in terms of peripherals, once they are moved to a networked classroom they can be plugged in to the local school network and thus avail of the use of common resources such as file servers, internet access etc. They can be used by teachers or pupils either individually or in small groups and could accommodate both task-oriented activities and self-directed learning. On of the advantages of Media Bays is the flexibility they facilitate, allowing resources to be moved quickly to classrooms or other school areas as required. If the Media bay includes a small hub or switch connected as shown, it requires only one network connection to connect all elements to the network. Fig 6a: Movable or mobile Media Bays with one network connection Laptop and Data Projector (Ref Fig 6b) A combination of laptop and data-projector is a highly effective teaching solution model where a teacher wants to provide the whole class with visual or multimedia content. It can be used in conjunction with an existing LAN point in the room for best effect. By connecting to the network the whole class can access content from the internet etc. Fig 6b: Movable or mobile Laptop PC with Digital Projector Wireless LAN (Ref Fig 6c) A Wireless LAN solution has the capability to connect multiple computers to the school LAN without providing direct LAN connections between the computers and the network. No LAN cabling is required for the classroom; instead all computers are radio linked to the LAN. Wireless LAN technology is relatively new and generally more expensive and more limited than standard cabled LANs. Wireless LAN data rates are typically slower than CAT5e LAN cabling. There is the potential, however, to save on cabling a particular school area by using the wireless option. Wireless connections allow a region to be connected to a network by radiowaves, which link a wireless card in the computer to a wireless access point. One should remember that the access point itself must be connected by cable to the local school network for the solution to work. NCTE Guidelines for Schools Networking 7
  • 8. Advantages • Flexibility of setting up networks - a network could be quickly set up, this may be especially appropriate in a situation where the network needs may change in the future, and where the cabling investment might be lost if further building changes were required. • Wireless networking means that large common areas such as school canteens or libraries can be easily connected to the network. Disadvantages • Wireless networking may prove more expensive if wiring large numbers of computers which are close together, as is the case in a computer room. Generally in this case it is best to cable the computer room rather that use a wireless network. • Wireless access point data rates of 11Mbps are considerably less at present than their cabled equivalent and thus is unsuitable for high data volumes such as multimedia access by large numbers of machines, however newer 54Mb/sec data rates are available which can better support multimedia. • Manufacturers stated ranges of 100 - 300 metres do not work satisfactorily in practice expecially where walls exist between the points in question. Ranges of less than 18 metres are not uncommon. Data rates drop off as distance increases. Concrete or block walls will also affect whether wireless will operate effectively in a particular school environment. Where older thicker walls are in place, this makes it more difficult if not impossible to deploy wireless networking. • There are security implications of using a wireless network, such that it may be possible for a external party to access the school network using certain equipment. If the nature of the data is sensitive and not to be viewed by external parties then the school should seek advice from in terms of the solution to be deployed, especially if the data if either sensitive or important. While it is unlikely that wireless will replace data cables in the near future they do provide a flexibility that can be harnessed creatively. Fig 6c: Wireless LAN (WLAN) NCTE Guidelines for Schools Networking 8
  • 9. 1.2. Costs of Networking: The costs of networking a school or a section of a school can be better understood by reviewing the items that contribute to the costs. Indicitive prices are outlined in Tables 2 -6 as a guideline, though these will vary. Professionally installed structured cabling to CAT5e standard is assumed, as anything of a lesser standard will generally cause problems, or have to be upgraded as schools needs change. Every school building is different with some local or particular requirements, so the table gives approximate costs for a single building situation. The outlined costs do not include the costs of PCs, Servers, Software etc. VAT applies at 21% for equipment and at 13.5% for services. Installation is a service and as such should have the appropriate VAT rate included. Price Networking Component Comment (ExVAT) Cabling (to Min CAT5e standard) Includes CAT5e cable, Installation, Patch leads, Cabling per network point €100-160 Device leads, trunking, Patch panels, Testing and Certification (includes cable and service) 15U (ie 18 inches high) Wall Cabinet is used to Wall Cabinet €200 house/protect cables/patch panels Standard Networking (ie Wired networks) Installed in each PC to allow connection to the Standard Network card €20-50 network Wireless Networking (11 or 54Mb/sec) NCTE recommend using the newer 54Mb/sec version Installed in each PC to allow connection to a Wireless Wireless PC Card €50-100 network Wireless Access Point (or Basestation) or A Wireless Access Point communicates with Wireless €350-600 Wireless Router PCs Switches/Hubs Switches rather than Hubs are recommended for Switch (24 port) €250-500 connecting PCs Hubs are older technology which are not generally Hub (8 port) €40 recommended in the main local area network Table 1: Network Components typical pricing for a school single building Example 1: Large Post Primary School with 800 pupils want to add a new computer room with 30 networked computers, ie 30 networked points. Totals Networking a computer room with 30 Unit Qty (ex points Cost VAT) €15 Cabling per network point 30 €4,500 0 €24 Wall Cabinet 1 €240 0 Standard Network card (one per PC) 30 €35 €1,050 €40 Switch (24 port) 2 €800 0 Totals €6,590 Table 2: Networking a new computer room with 30 networked computers NCTE Guidelines for Schools Networking 9
  • 10. Model Pricing to network one classroom/office with 2 network points. This table gives an indication as to what it would cost to network just one classroom. The model is provided so that schools can use it as a base Totals Network 2 Classrooms (with 2 Unit Qty (ex network points per classroom) Cost VAT) €16 Cabling per network point 4 €640 0 €24 Wall Cabinet 1 €240 0 Standard Network card (one per PC) 2 €25 €50 €40 Switch (24 port) 1 €400 0 Totals €1,330 Table 3: Networking one room with 2 network points Example 2: Large Primary School with 350 pupils want to network an additional 12 classrooms with 2 networking points per classroom. Totals Network 12 Classrooms (with 2 points Unit Qty (ex network points per classroom) Cost VAT) €16 Cabling per network point 24 €3,840 0 €24 Wall Cabinet 1 €240 0 Standard Network card (one per PC) 24 €25 €600 €40 Switch (24 port) 1 €400 0 Totals €5,080 Table 4: Networking 12 rooms with 2 network points each Example 3: Large Post Primary School with 800 pupils want to add a wireless network of 24 PCs to the science lab. Totals Add a Wireless Network of 24 PCs to Unit Qty (ex the Science Lab Cost VAT) Cabling per network point (for Wireless €15 3 €450 Access Points) 0 €24 Wall Cabinet 1 €240 0 Wireless PC Card 24 €75 €1,800 €50 Wireless Access Point 3 €1,500 0 €40 Switch (24 port) 1 €400 0 NCTE Guidelines for Schools Networking 10
  • 11. Totals €4,390 Table 5: Networking a Lab with 24 wireless accessible points 3 wireless Access points are used in this example to increase the bandwidth per access point, however 2 or even 1 wireless access point could be used but with the limitation of reduced bandwidth of 11Mbps for the whole lab. NCTE Guidelines for Schools Networking 11
  • 12. Cabling Guidelines and recommendations: Cabling Recommendations: Structured cabling to be used throughout. All network points to be terminated on patch panels A minimum of CAT5e to be used, Cabling to CAT6 to be used for all new installations All cabling to be fully tested and a formal certification signoff to be obtained from the supplier. Cabling to be carried out only by qualified personnel. Number of Networking Points required: (ref DES Building Unit Guidelines) This section details the approved provision of points for the various rooms and areas in a school and the approved density. All teaching and habitable rooms should be networked. Each of these rooms should have two networked points at appropriate areas. In specialist rooms other I.T. points are to be provided as indicated and these shall be networked through a local switch or to the MDF or IDF which ever is the most economical. Table 2 below gives recommended number of network points to be included for various room/spaces. These recommendations may change so please do consult the NCTE website to check the number of recommended network before finalising your network, or expansion. Local Area Network (LAN) Points. TPNP = Teacher Position Network Point. SPNP = Student Position Network Point. NP = Network point in non-teaching Spaces. Type of Room/Space. Network Points. General Classroom 1 TPNP + 4 SPNP (distributed around room) Computer Room 1 TPNP + 30 SPNP 2 student printer NP Science Laboratory Preparation Area 1 TPNP + 6 SPNP Lab. 1 NP Prep. Area. Learning Support Room 1 TPNP + 6 SPNP Language Room 1 TPNP + 4 SPNP Multimedia Learning Laboratory 1 TPNP + 30 SPNP + 2 student printer NP. Physics Laboratory Preparation Area 1 TPNP + 6 SPNP Lab. 1 NP Prep. Area. Art/Craft Room & Store 1 TPNP + 6 SPNP Home Economics 1 TPNP + 4 SPNP Word Processing/ 1 TPNP + 30 SPNP + Keyboarding Skills Room 2 printer NP Business Studies/Commerce 1 TPNP + 4 SPNP Technical Graphics /Cad 1 TPNP + 6 SPNP Construction Studies/ 1 TPNP + 6 SPNP Wood Technology Room Technology Room. 1 TPNP + 6 SPNP Wood/Technology Machining & Prep area 1 NP Engineering/Metal Technology Room 1 TPNP + 6 SPNP Library & Ancillary Stores 100 m2 1 TPNP + 8 SPNP Library & Ancillary Stores 136 m2 1 TPNP + 11 SPNP Principal’s Office. 2 NP Deputy Principal’s Office. 2 NP General Office. 30 m2 3 NP + 1 printer NP. General Office. 20 m2 2 NP + 1 printer NP Staff Room 2 NP 200 – 499 Pupils 4 NP 500 + Pupils Meeting Room 2 NP P.E.Hall / PE Balcony 1 NP in each Music/Drama Area 1 TPNP + 4 SPNP NCTE Guidelines for Schools Networking 12
  • 13. Guidance Suite: 1 TPNP + 4 SPNP (1 classroom +1 office) 1 NP office Social Studies Room 1 TPNP + 4 SPNP Home School Community Liaison. (Classroom + 1 TPNP + 4 SPNP office) 1 NP office Religion Room, Meditation Area 1 TPNP Chaplain’s Office 1 NP office Table 6: Local Area Network (LAN) Points 1.3. Basics of Networking A computer network consists of a collection of computers, printers and other equipment that is connected together so that they can communicate with each other (see Advice Sheet 17 on the ICT Planning for schools pack). Fig 1 gives an example of a network in a school comprising of a local area network or LAN connecting computers with each other, the internet, and various servers. Access to: File and Print Server Internet content & CD or Multimedia learning resources, Servers Scoilnet etc Printers , Scanners etc Users Email communication computers Cache, Proxy, Filtering, Firewall Server School ‘Local Area Network’ (LAN) Modem or Router Other users, computers Fig 7: Representation of Network in a school. Broadly speaking, there are two types of network configuration, peer-to-peer networks and client/server networks. Peer-to-peer networks are more commonly implemented where less then ten computers are involved and where strict security is not necessary. All computers have the same status, hence the term 'peer', and they communicate with each other on an equal footing. Files, such as word processing or spreadsheet documents, can be shared across the network and all the computers on the network can share devices, such as printers or scanners, which are connected to any one computer. NCTE Guidelines for Schools Networking 13
  • 14. Peer to Peer Network Fig 8: Peer to Peer Networking Client/server networks are more suitable for larger networks. A central computer, or 'server', acts as the storage location for files and applications shared on the network. Usually the server is a higher than average performance computer. The server also controls the network access of the other computers which are referred to as the 'client' computers. Typically, teachers and students in a school will use the client computers for their work and only the network administrator (usually a designated staff member) will have access rights to the server. File Server Other equipment Fig 9: Client - Server Networking NCTE Guidelines for Schools Networking 14
  • 15. Table 7 provides a summary comparison between Peer-to-Peer and Client/Server Networks. Peer-to-Peer Networks vs Client/Server Networks Peer-to-Peer Networks Client/Server Networks · Easy to set up · More difficult to set up · Less expensive to install · More expensive to install · A variety of operating systems can be supported on · Can be implemented on a wide range of the client computers, but the server needs to run an operating systems operating system that supports networking · More time consuming to maintain the · Less time consuming to maintain the software being software being used (as computers must be used (as most of the maintenance is managed from managed individually) the server) · High levels of security are supported, all of which · Very low levels of security supported or none are controlled from the server. Such measures prevent at all. These can be very cumbersome to set up, the deletion of essential system files or the changing depending on the operating system being used of settings · Ideal for networks with less than 10 · No limit to the number of computers that can be computers supported by the network · Does not require a server · Requires a server running a server operating system · Demands that the network administrator has a high · Demands a moderate level of skill to level of IT skills with a good working knowledge of a administer the network server operating system Table 7: Peer-to-Peer Networks vs Client/Server Networks Components of a Network A computer network comprises the following components: • A minimum of at least 2 computers • Cables that connect the computers to each other, although wireless communication is becoming more common (see Advice Sheet 20 for more information) • A network interface device on each computer (this is called a network interface card or NIC) • A ‘Switch’ used to switch the data from one point to another. Hubs are outdated and are little used for new installations. • Network operating system software Structured Cabling The two most popular types of structured network cabling are twisted-pair (also known as 10BaseT) 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 Video Recorder to a TV. 10BaseT Cabling When 10BaseT cabling is used, a strand of cabling is inserted between each computer and a hub. If you have 5 computers, you'll need 5 cables. Each cable cannot exceed 325 feet in length. Because the cables from all of the PCs converge at a common point, a 10BaseT network forms a star configuration. Fig 10a shows a Cat5e cable, with a standard connector, known as an RJ-45 connector. Fig 10b shows a standard Cat5e Wall Outlet socket which the cables are connected to. Fig 10c shows a standard Cat5e Patch Panel Wall Outlet socket which is used to terminate the cables from various points in the school bank to a central point. Fig 10d shows a wall mounted cabinet used to house and protect patch panel cables and connectors. NCTE Guidelines for Schools Networking 15
  • 16. Fig 10a: Cat5e Cable and a close up of RJ-45 connector Fig 10b: Cat5e Wall Outlets Fig 10c: Cat5e Patch Panel Fig 10d: Wall Mounted Cabinet 10BaseT cabling is available in different grades or categories. Some grades, or "cats", are required for Fast Ethernet networks, while others are perfectly acceptable for standard 10Mbps networks--and less expensive, too. All new networks use a minimum of standard unshielded twisted-pair (UTP) Category 5e 10BaseT cabling because it offers a performance advantage over lower grades. Network Interface Card (NIC) A NIC (pronounced 'nick') is also known as a network card. It connects the computer to the cabling, which in turn links all of the computers on the network together. Each computer on a network must have a network card. Most modern network cards are 10/100 NICs and can operate at either 10Mbps or 100Mbps. Only NICs supporting a minimum of 100Mbps should be used in new installations schools. Computers with a wireless connection to a network also use a network card (see Advice Sheet 20 for more information on wireless networking). NCTE Guidelines for Schools Networking 16
  • 17. Fig 11: Network Interface Cards (NICs) Hub and Switch A hub is a device used to connect a PC to the network. The function of a hub is to direct information around the network, facilitating communication between all connected devices. However in new installations switches should be used instead of hubs as they are more effective and provide better performance. A switch, which is often termed a 'smart hub'. Switches and hubs are technologies or ‘boxes’ to which computers, printers, and other networking devices are connected. Switches are the more recent technology and the accepted way of building today's networks. With switching, each connection gets "dedicated bandwidth" and can operate at full speed. In contrast, a hub shares bandwidth across multiple connections such that activity from one PC or server can slow down the effective speed of other connections on the hub. Now more affordable than ever, Dual-speed 10/100 autosensing switches are recommended for all school networks. Schools may want to consider upgrading any hub based networks with switches to improve network performance – ie speed of data on the network. Fig 12a: An 8 port Hub Fig 12b: 2 Examples of 24 port Switches Wireless Networks The term 'wireless network' refers to two or more computers communicating using standard network rules or protocols, but without the use of cabling to connect the computers together. Instead, the computers use wireless radio signals to send information from one to the other. A wireless local area network (WLAN) consists of two key components: an access point (also called a base station) and a wireless card. Information can be transmitted between these two components as long as they are fairly close together (up to 100 metres indoors or 350 metres outdoors). NCTE Guidelines for Schools Networking 17
  • 18. Fig 13a: Wireless Access point or Wireless Basestation Suppliers would need to visit the schools and conduct a site survey. This will determine the number of base stations you need and the best place(s) to locate them. A site survey will also enable each supplier to provide you with a detailed quote. It is important to contact a number of different suppliers as prices, equipment and opinions may vary. When the term 'wireless network' is used today, it usually refers to a wireless local area network or WLAN. A WLAN can be installed as the sole network in a school or building. However, it can also be used to extend an existing wired network to areas where wiring would be too difficult or too expensive to implement, or to areas located away from the main network or main building. Wireless networks can be configured to provide the same network functionality as wired networks, ranging from simple peer-to-peer configurations to large-scale networks accommodating hundreds of users. Fig 13b: Desktop PC Wireless LAN card Fig 13c: Laptop PC Wireless LAN card What are the advantages and disadvantages of a Wireless LAN? Wireless LANs have advantages and disadvantages when compared with wired LANs. A wireless LAN will make it simple to add or move workstations, and to install access points to provide connectivity in areas where it is difficult to lay cable. Temporary or semi-permanent buildings that are in range of an access point can be wirelessly connected to a LAN to give these buildings connectivity. Where computer labs are used in schools, the computers (laptops) could be put on a mobile cart and wheeled from classroom to classroom, providing they are in range of access points. Wired network points would be needed for each of the access points. A WLAN has some specific advantages: • It is easier to add or move workstations • It is easier to provide connectivity in areas where it is difficult to lay cable • Installation can be fast and easy and can eliminate the need to pull cable through walls and ceilings • Access to the network can be from anywhere in the school within range of an access point • Portable or semi-permanent buildings can be connected using a wireless LAN • While the initial investment required for wireless LAN hardware can be similar to the cost of wired LAN hardware, installation expenses can be significantly lower • Where a school is located on more than one site (such as on two sides of a road), it is possible with directional antennae, to avoid digging trenches under roads to connect the sites • In historic buildings where traditional cabling would compromise the façade, a wireless LAN can avoid drilling holes in walls • Long-term cost benefits can be found in dynamic environments requiring frequent moves and changes • They allows the possibility of individual pupil allocation of wireless devices that move around the school with the pupil. WLANs also have some disadvantages: • As the number of computers using the network increases, the data transfer rate to each computer will decrease accordingly NCTE Guidelines for Schools Networking 18
  • 19. • As standards change, it may be necessary to replace wireless cards and/or access points • Lower wireless bandwidth means some applications such as video streaming will be more effective on a wired LAN • Security is more difficult to guarantee, and requires configuration • Devices will only operate at a limited distance from an access point, with the distance determined by the standard used and buildings and other obstacles between the access point and the user • A wired LAN is most likely to be required to provide a backbone to the wireless LAN; a wireless LAN should be a supplement to a wired LAN and not a complete solution • Long-term cost benefits are harder to achieve in static environments that require few moves and changes • It is easier to make a wired network ‘future proof’ for high data transfer. Wireless Network Components There are certain parallels between the equipment used to build a WLAN and that used in a traditional wired LAN. Both networks require network interface cards or network adapter cards. A wireless LAN PC card, which contains an in-built antenna, is used to connect notebook computers to a wireless network. Usually, this is inserted into the relevant slot in the side of the notebook, but some may be internal to the notebook. Desktop computers can also connect to a wireless network if a wireless network card is inserted into one of its internal PCI slots. In a wireless network, an 'access point' has a similar function to the hub in wired networks. It broadcasts and receives signals to and from the surrounding computers via their adapter card. It is also the point where a wireless network can be connected into an existing wired network. The most obvious difference between wireless and wired networks, however, is that the latter uses some form of cable to connect computers together. A wireless network does not need cable to form a physical connection between computers. Benefits and Educational Uses The installation of cables is time consuming and expensive. The advantages of not doing so are apparent: • the amount of work required and the time taken to complete it are significantly reduced • the network is accessible in places where wiring would have been difficult or impossible • with no cables linking computers together, cable-related faults and network downtime are minimised • Where a wireless network is in place, teachers or students can have continuous access to the network, even as they move with their equipment from class to class. • The space over which a wireless network operates is not planar but spherical. Therefore, in a multi- level school, network access could be available in rooms above or below the access point, without the need for additional infrastructure. • In a location within a school where network access is required occasionally, desktop computers fitted with wireless network cards can be placed on trolleys and moved from location to location. They can also be located in areas where group work is taking place. As they are connected to the network, documents and files can be shared, and access to the Internet is available, enhancing group project work. • As the range of the wireless network extends outside the building, students and teachers can use wireless devices to gather and record data outside, e.g., as part of a science experiment or individual performance data as part of a PE class. Technical and Purchasing Considerations Network interface cards for wireless networks are more expensive than their wired counterparts. The cost of the access points has also to be considered. Wireless networks work at 11Mbps, whereas wired networks normally work at100Mbps (Fast Ethernet). This data transmission rate is dependant on the number of users, the distance from the access point and the fabric of the building (metal structures in walls may have an impact). A wireless network will be noticeably slow when a group of users are transferring large files. This should be considered if multimedia applications are to be delivered over the network to a significant number of users. NCTE Guidelines for Schools Networking 19
  • 20. As the range of the network may extend beyond the walls of the building, it can be accessed from outside. Consideration should be given to what security features the equipment provides to ensure that only valid users have access to the network and that data is protected. 1.4. Advantages of Networking schools Speed. Networks provide a very rapid method for sharing and transferring files. Without a network, files are shared by copying them to floppy disks, then carrying or sending the disks from one computer to another. This method of transferring files in this manner is very time-consuming. Cost. The network version of most software programs are available at considerable savings when compared to buying individually licensed copies. Besides monetary savings, sharing a program on a network allows for easier upgrading of the program. The changes have to be done only once, on the file server, instead of on all the individual workstations. Centralized Software Management. One of the greatest benefits of installing a network at a school is the fact that all of the software can be loaded on one computer (the file server). This eliminates that need to spend time and energy installing updates and tracking files on independent computers throughout the building. Resource Sharing. Sharing resources is another area in which a network exceeds stand-alone computers. Most schools cannot afford enough laser printers, fax machines, modems, scanners, and CD-ROM players for each computer. However, if these or similar peripherals are added to a network, they can be shared by many users. Flexible Access. School networks allow students to access their files from computers throughout the school. Students can begin an assignment in their classroom, save part of it on a public access area of the network, then go to the media center after school to finish their work. Students can also work cooperatively through the network. Security. Files and programs on a network can be designated as "copy inhibit," so that you do not have to worry about illegal copying of programs. Also, passwords can be established for specific directories to restrict access to authorized users. Main challenges to be addressed relating to Networking Costs Although a network will generally save money over time, the initial costs can be substantial, and the installation will require the services of a technician or other experienced IT person. Requires Administrative Time. Proper maintenance of a network requires considerable time and expertise. Many schools have installed a network, only to find that they did not budget for the necessary administrative support. Server Failure Although a server is no more susceptible to failure than any other computer, when the files server "goes down," the entire network may come to a halt. When this happens, the entire school may lose access to necessary programs and files. As such all important files should be backed up so that it the server does fail that the data is recoverable. Digital Audio tape (DAT) or tape backup are the most commonly used options. NCTE Guidelines for Schools Networking 20
  • 21. 2.1. Some Relevant Terms LAN Local Area Network Ethernet Ethernet is a standard for transferring data over networks. USB Universal Serial Bus Modem A simple device used to access the internet Router A more technically advanced device used to access the internet Mbps Megabits per second (1,000,000 bits per second) Kbps Kilobits per second (1,000 bits per second) MDF Main Distribution Frame IDF Intermediate Distribution Frame Broadband Refers to a higher speed always on internet connection Narrowband Refers to speeds of up to 128kbps Dial up Refers to having to dial up the internet every time one goes online. Always On Refers to the nature of broadband, being ‘always on’ means a dial up is not required. Download speed The speed at which data is delivered to a school modem from the internet Upload speed The speed at which data is sent to the internet from a school modem. ISP Internet Service Provider ISDN Integrated Services Digital Network (64kbps single channel or 128kbps dual channel) PSTN Public Switched Telephone Network (refers to an ordinary telephone line) ADSL Asymmetric Digital Subscriber Loop Last page of Document NCTE Guidelines for Schools Networking 21