Unit 106: Principles of Computer Networks NQF Level 3: BTEC National Guided learning hours: 60 Unit abstract Learners thinking of careers within network technical support or network management must have a good understanding of the underlying principles of networking and how data travels around networks. This unit starts by exploring the different types of networks and the standards relating to network systems, including local and wide area networks. Networks can be either wired or wireless systems and, although much of the underpinning content is similar, this unit does make reference to both. The hardware and software components used in networks and their operation are explored and learners will build an understanding of their functions and services and how they relate to each other. As users of networks, we work with them mostly through the services that they provide, from simple services such as file sharing and communications to more complex services involving security and account management. For networks to be practical, they must be secure and the nature of them being distributed across several physical locations, perhaps via a WAN, makes the ensuring of security a complex business. Learners will understand key network security issues as well as exploring the technologies used to create secure systems. Learning outcomes On completion of this unit a learner should: 1 Know the types of network systems and related standards 2 Understand the hardware and software used in networking 3 Know the services provided by network systems 4 Understand how networked systems are made secure. 1 Unit content 1 Know the types of network systems and related standards Types of network: local area network (LAN); wide area network (WAN); WAN technologies eg frame relay, ISDN, ATM; value added network (VAN); logical and physical topologies eg star, bus, ring, mesh; network access methods eg CSMA, Token passing; OSI 7 layer model; choice of network to meet business need Network protocols and standards: eg TCP/IP, AppleTalk, UDP, 802.2, 802.3, FDDI, 802.5; wireless technologies eg 802.11, infrared, Bluetooth; factors affecting range and speed of wireless technologies Application layer protocols: eg DNS, DHCP; HTTP; FTP; SMTP 2 Understand the hardware and software used in networking Network devices: workstations; servers eg print, mail, file, web, proxy; others eg network interface cards (NIC); features and functions Interconnection devices: eg modem, repeater, bridge, router, gateway, switch, hub; wireless access points; purposes, features and functions Connectors and cabling: leased line; dedicated line; media types eg STP, Category 5, coaxial, UTP, fibre optic; wireless; microwave and satellite links; cable standards eg 10Base-T Software: network operating system; virus checker; firewall; other eg email client Commercial systems: eg Unix, Linux, Windows, Netware, Appleshare 3 Know the services provided by network systems Directory services: eg account management, authentication management Telecommunication services: communication eg email, internet relay chat (IRC), discussion boards; remote access eg via mobiles File services: file transfer; file sharing Application services: application software eg database, web, proxy; shared resources printing; storage space; Voice over IP (VoIP); mobile working; authentication eg users, hardware 4 Understand how networked systems are made secure Risk related business issues: risks to business; costs; responsibilities; systems and procedures eg password policies; disaster recovery; comparison with security issues for non-networked systems Securing data: authorisation permissions and access control lists; backing up and restoring; encrypting; others eg biometrics; physical security eg CCTV, locks Software: firewalls; malware (hostile, intrusive, or annoying software or program code) eg viruses, Trojans, worms, spyware, adware; levels of security risk for different malware; software protection eg antivirus, intrusion detection systems 2 Grading grid In order to pass this unit, the evidence that the learner presents for assessment needs to demonstrate that they can meet all of the learning outcomes for the unit. The criteria for a pass grade describe the level of achievement required to pass this unit. Grading criteria To achieve a pass grade the evidence must To achieve a merit grade the evidence must To achieve a distinction grade the evidence show that the learner is able to: show that, in addition to the pass criteria, must show that, in addition to the pass and the learner is able to: merit criteria, the learner is able to: P1 describe the types of networks available M1 compare the benefits and disadvantages of D1 justify the design and choice of and how they relate to particular network peer-to-peer network and client/server components used in a particular standards and protocols networks networked solution P2 describe, using examples, why different M2 design a networked solution to meet a D2 evaluate the value of typical services network standards and protocols are particular situation with specific available from a network operating system necessary requirements directory service. P3 describe the functions of a logical set of M3 compare and explain the differences in interconnection devices data transfer rates between typical LANs, WANs and mobile networks P4 describe the key components required for M4 explain the importance of the OSI seven client workstations to connect to a layer model. network and access network resources P5 give an outline description of the seven layer OSI model P6 describe typical services provided by networks P7 describe the business risks of insecure networks and how they can be minimised. Page 3 of 8 Essential guidance for tutors Delivery This unit is based on the principles of networking with a theoretical view to much of the content. However, centres should try to ensure that as many varied learning approaches are used as possible. Practical activities on real networks are recommended, examples are offered in Assessment below. Visits or talks given by outside professionals will be valuable — preparation may be necessary to ensure that the guest speaker understands the level of programme and is prepared to use appropriate language and respond to the learning outcomes where possible. Assessment As this unit has substantial theory it is important that centres make as much use of varied assessment strategies as possible to maintain interest. This could include the use of online or conventional testing, learner presentations, assignments or question and answer sessions. To achieve a pass grade, learners must achieve the seven pass criteria listed in the grading grid. For P1, learners could produce a report using diagrams. Alternatively, a small set of linked web pages could be appropriate. For P2, technical detail can be limited but learners should be able to demonstrate their awareness, perhaps via a written or verbal report or presentation that they understand why different network standards and protocols are necessary. Examples given should be realistic. For P3, an observation sheet documenting and summarising a series of questions and answers or discussion would be appropriate, alternatively a simple test. Most of the related content is indicative, however it is important that the set represents a logical set of components rather than a random list. The centre can provide scenarios. For P4, ideally learners should have the opportunity to set up a basic network and the actual evidence of the network (photos, diagrams etc) could be supported by a confirmation by observation record that this constructed network actually functions. Learners would probably welcome the opportunity to talk through what they did and this provides additional valuable evidence, alternatively log book evidence can be used if needed. For P5 and P6, a written report, presentation or set of web pages could be an appropriate vehicle to provide the evidence. For P7, learners could produce a report based on a centre-provided case study, however the case study must be sufficiently rich to allow a wide range of issues to be identified as relevant. Basing a report on a visit to a real company would be of particular value and if this results in a restricted report then additional evidence can be added via a documented post-visit discussion prompted by the tutor. For example ‘I know that the company you visited did not have their network connected to the internet but if they did what other security risks might that bring?’. Or ‘I know that the company you visited does not have a disaster recovery policy in place but what do you think that this should include?’. To achieve a merit grade, learners must achieve all of the pass grade criteria and the four merit grade criteria. For M1, learners should, ideally, have the chance to see the operation of both types of networks and then the actual evidence presented as verbal, written report etc would be based on real experience. The evidence for M2 could evolve from that produced for P4 as long as a clear set of specifications were available to be checked against. A scenario could be provided by the centre For M3, learners could use a simple table to summarise some key exemplar data and then make references to this in an accompanying report. Ideally, learners would be able to derive the performance data from actual experiments on real systems. For M4, a simple written report is the most obvious, however a short presentation would also be appropriate. To achieve a distinction grade, learners must achieve all of the pass and merit grade criteria and the two distinction grade criteria. For D1 and D2, written reports or presentations would both be appropriate. Links to National Occupational Standards, other BTEC units, other BTEC qualifications and other relevant units and qualifications This unit can be linked with Unit 100: Computer Systems, Unit 102: Maintaining Computer Systems, Unit 107: Network Management, Unit 108: Networked Systems Security, Unit 109: Networking Basics (Cisco CCNA1) and Unit 110: Routers and Routing Basics (Cisco CCNA2). This unit has links to the Level 3 National Occupational Standards for CT Practitioners. Essential resources The tutor will need access to a LAN to demonstrate the configuration of protocols and services. If a lab network is available, the tutor can demonstrate the connectivity of hubs, routers, switches, etc. If it is not available, learners should at least see the various interconnectivity devices. If a lab network is available, learners can configure IP settings and create shared folders to access across the network. The tutor should be able to demonstrate network security settings and should have access to a range of security application software, including a firewall. Indicative reading for learners Textbooks Burgess M — Principles of Network and System Administration, 2nd Edition (John Wiley and Sons Ltd, 2003) ISBN 0470868074 Malik S — Network Security Principles and Practices (Cisco Press, 2002) ISBN 1587050250 Olifer N and Olifer V — Computer Networks: Principles, Technologies and Protocols for Network Design (John Wiley and Sons Ltd, 2005) ISBN 0470869828 Sybex — Networking Complete (John Wiley and Sons Ltd, 2001) ISBN 0782129145 Key skills Achievement of key skills is not a requirement of this qualification but it is encouraged. Suggestions of opportunities for the generation of level 3 key skill evidence are given here. Tutors should check that learners have produced all the evidence required by part B of the key skills specifications when assessing this evidence. Learners may need to develop additional evidence elsewhere to fully meet the requirements of the key skills specifications. Application of number Level 3 When learners are: They should be able to develop the following key skills evidence: • designing a networked N3.1 Plan an activity and get relevant solution to meet a particular information from relevant sources. situation with specific requirements. N3.2 Use this information to carry out multi- stage calculations to do with: a amounts or sizes b scales or proportion c handling statistics d using formulae. N3.3 Interpret the results of your calculations, present your findings and justify your methods. Communication Level 3 When learners are: They should be able to develop the following key skills evidence: • describing the functions of a C3.1a Take part in a group discussion. logical set of interconnection devices. C3.1b Make a formal presentation of at least eight minutes using an image or other support material. C3.2 Read and synthesise information from at least two documents about the same subject. Each document must be a minimum of 1,000 words long. C3.3 Write two different types of documents each one giving different information about complex subjects. One document must be at least 1,000 words long. Information and communication technology Level 3 When learners are: They should be able to develop the following key skills evidence: • describe the types of ICT3.1 Search for information, using different networks available and how sources, and multiple search criteria in at they relate to particular least one case. network standards and protocols ICT3.2 Enter and develop the information and derive new information. ICT3.3 Present combined information such as text with image, text with number, image with number. Improving own learning and performance Level 3 When learners are: They should be able to develop the following key skills evidence: • designing a networked LP3.1 Set targets using information from solution to meet a particular appropriate people and plan how these situation with specific will be met. requirements. LP3.2 Take responsibility for your learning, using your plan to help meet targets and improve your performance. LP3.3 Review progress and establish evidence of your achievements. Problem solving Level 3 When learners are: They should be able to develop the following key skills evidence: • designing a networked PS3.1 Explore a problem and identify different solution to meet a particular ways of tackling it. situation with specific requirements. PS3.2 Plan and implement at least one way of solving a problem. PS3.3 Check if the problem has been solved and review your approach to problem solving. Working with others Level 3 When learners are: They should be able to develop the following key skills evidence: • designing a networked WO3.1 Plan work with others. solution to meet a particular situation with specific requirements. WO3.2 Seek to develop co-operation and check progress towards your agreed objectives. WO3.3 Review work with others and agree ways of improving collaborative work in the future.
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