Level 3 Digital Technologies 91636 44) Specific Assessment Guides Complexity and Tractability: 1–4 Formal Languages: 5–8 Graphics and Visual Computing: 9–12 Intelligent Systems: 13–16 Network Communication Protocols: 17–20 Software

Level 3 Digital Technologies 91636 (3.44) Specific Assessment Guide (Network Communication Protocols)

Title Demonstrate understanding of areas of computer science
Credits 4

Teacher introduction

Technology assessment guides have been produced to help teachers develop their own specific assessment guides. Examples of specific assessment guides, developed from the common assessment guide for each standard, have been produced as part of the external assessment resources for level 3 Technology.

The specific assessment guides also show a variety of ways (ie case study, research, practice) to produce external assessment material. The material in the candidate exemplars for each standard reflects the content and context of the specific assessment guides.

Teachers can adapt a common assessment guide and / or a specific assessment guide to suit the specific context of their course of teaching.

Candidate introduction

You will produce a report that demonstrates understanding of areas of computer science. To complete the report you will need to report on at least two of the Areas of Computer Science from explanatory note 3 in the standard.

This specific assessment guide is one of six. Each one of the specific assessment guides relate to one of the six Areas of Computer Science.

Candidate guidance for producing the report

There are some prompts and activities below that will assist you to write the part of your report on network communication protocols. The prompts will help you to produce a report that demonstrates the understanding expected in this assessment. The prompts also define the levels of description, explanation, and discussion that are expected at each grade.

To demonstrate understanding of areas of computer science at the Achieved level you will need to:

• 
  describe key problems that are addressed in selected areas of computer science
  
• 
  describe examples of practical applications of selected areas to demonstrate the use of key algorithms and/or techniques from these areas.
  

To demonstrate in-depth understanding of areas of computer science at the Merit level you will need to:

• 
  explain how key algorithms or techniques are applied in selected areas
  
• 
  explain examples of practical applications of selected areas to demonstrate the use of key algorithms and/or techniques from these areas.
  

To demonstrate comprehensive understanding of areas of computer science at the Excellence level you will need to:

• 
  discuss examples of practical applications of selected areas to demonstrate the use of key algorithms and/or techniques from these areas
  
• 
  evaluate the effectiveness of algorithms, techniques, or applications from selected areas.
  

Possible Activities

The activities below are activities which generate specific content that you can use to develop your report. For example, if you were to Use tools like traceroute to evaluate the time taken and number of hops required for packets to be transmitted through the internet (see activity 1 below) you could generate information related to several parts of the report.

21. 
    Use tools like traceroute to evaluate the time taken and number of hops required for packets to be transmitted through the internet.
    
22. 
    Using packet analyser software (eg wireshark), trace the sequence of exchanges that occur for a protocol such as DNS, UDP, or HTTP using an example on your own system.
    
23. 
    Participate in and document the ‘tablets of stone’ activity (http://csi.dcs.gla.ac.uk/workshop-view.php?workshopID=4).
    
24. 
    Explain how HTTP provides the foundation of the world wide web, how IP solves the problem of individually addressing the thousands of computers that comprise the internet, and / or how DNS makes the internet friendly for human users.
    
25. 
    Use tools to show how encryption algorithms and security protocols can provide confidentiality, integrity, and availability of information exchanged between parties.
    

Essential documents

The achievement standard governing this specific assessment guide can be found at
http://www.nzqa.govt.nz/nqfdocs/ncea-resource/specifications/2013/level3/91636-spc-2013.pdf

The assessment specifications for the Digital Technologies achievement standard can be found at

http://www.nzqa.govt.nz/nqfdocs/ncea-resource/achievements/2013/as91636.pdf

Definitions

The following are concepts, algorithms, techniques, applications, and problems that students at level 3 are likely to be able to work with; it is not a list of all the key ideas in the area.

Key concepts likely to be encountered are: addressing, reliability, security, failure, packet loss, human-readable addresses, quality of service, network performance, cyber attacks, and routing.

Algorithms: (techniques are more relevant to this area than algorithms)

Techniques: packet switching, handshaking, acknowledgement, authentication, checksums, wireless and wired security.

Applications: many real protocols (eg TCP/IP) could rapidly become overwhelming at this level. Protocols that students could investigate that are less complex are DNS, UDP, HTTP (get and post), the addressing part of IP, SMTP and CDMA, and internet security protocols such as SSL, IPSec, and PGP.

Network communication protocols focus on the techniques applied in computer networks to ensure reliable communication of data between two parts of a network in the face of different kinds of threats and failures. The project would typically be done by giving examples of the sequence of events that occur in these situations, discussing how the protocols and their coding schemes overcome the problems, and evaluating how successful they are at addressing them. This topic is distinct from the coverage of networking in the infrastructure standards because it focuses on the issues that the protocols address (ie the design of the protocol), rather than how to configure a system that uses a given protocol.

Further information

Useful links:

• 
  http://en.wikipedia.org/wiki/Network_protocol
  
• 
  http://www.w3schools.com/tcpip/
  
• 
  http://computer.howstuffworks.com/internet/basics
  
• 
  http://csi.dcs.gla.ac.uk/workshop-view.php?workshopID=4
  
• 
  http://www.cbtnuggets.com/ (Cisco CCENT ICND1 640-822 series – free preview but fee for full access)
  
• 
  http://en.wikipedia.org/wiki/Cryptographic_protocol
  
• 
  http://www.povray.org/resources/links/3D_Tutorials/POV-Ray_Tutorials/
  

Further information can be found at http://www.techlink.org.nz.

Exemplars

Please read the exemplars. You can model your work on these exemplars but you may not copy the material from the exemplars. Your report must be the product of your own efforts.

Schedule

Assessment Schedule AS Digital Technologies 91636 (3.44) Demonstrate understanding of areas of computer science
Final grades will be decided using professional judgement based on a holistic examination of the evidence provided against the criteria.
Issues from the Specifications Authentic candidate submissions will be recognisable because of specific contexts associated with the work. This does not imply that submissions will arise only from the candidate’s practice. However, where the candidate’s practice does not provide the immediate source of a specific context, one would expect to see that several sources of information relating to materials had been applied within a specific context. In both cases, the marker will be able to detect the candidate’s voice. In situations where information does not have some aspect of student voice, it is difficult to establish whether the candidate has actually demonstrated understanding or simply identified information. Candidates who have simply identified information by reproducing information from sources without making use of that information have not demonstrated understanding. Where a candidate has provided a brief answer, the answer should not be penalised because of length. Candidate work in excess of 14 pages should not be marked. Where work is illegible, it cannot be marked. Digital submissions that cannot be read cannot be marked.
Achievement	Achievement with Merit	Achievement with Excellence
Demonstrating understanding of areas of computer science involves:	Demonstrating in-depth understanding of areas of computer science involves:	Demonstrating comprehensive understanding of areas of computer science involves:
describing key problems that are addressed in selected areas of computer science describing examples of practical applications of selected areas to demonstrate the use of key algorithms and/or techniques from the.se areas.	explaining how key algorithms or techniques are applied in selected areas explaining examples of practical applications of selected areas to demonstrate the use of key algorithms and/or techniques from these areas.	discussing examples of practical applications of selected areas to demonstrate the use of key algorithms and/or techniques from these areas evaluating the effectiveness of algorithms, techniques, or applications from selected areas.

Level 3 Digital Technologies 91636 (3.44) Specific Assessment Guide (Software Engineering)

Title Demonstrate understanding of areas of computer science
Credits 4

Teacher introduction

Technology assessment guides have been produced to help teachers develop their own specific assessment guides. Examples of specific assessment guides, developed from the common assessment guide for each standard, have been produced as part of the external assessment resources for level 3 Technology.

The specific assessment guides also show a variety of ways (ie case study, research, practice) to produce external assessment material. The material in the candidate exemplars for each standard reflects the content and context of the specific assessment guides.

Teachers can adapt a common assessment guide and / or a specific assessment guide to suit the specific context of their course of teaching.

Candidate introduction

You will produce a report that demonstrates understanding of areas of computer science. To complete the report you will need to report on at least two of the Areas of Computer Science from explanatory note 3 in the standard.

This specific assessment guide is one of six. Each one of the specific assessment guides relates to one of the six Areas of Computer Science.

Candidate guidance for producing the report

There are some prompts and activities below that will assist you to write the part of your report on software engineering. They will help you to produce a report that demonstrates the understanding expected in this assessment. The prompts also define the levels of description, explanation, and discussion that are expected at each grade.

To demonstrate understanding of areas of computer science at the Achieved level you will need to:

• 
  describe key problems that are addressed in selected areas of computer science
  
• 
  describe examples of practical applications of selected areas to demonstrate the use of key algorithms and/or techniques from these areas.
  

To demonstrate in-depth understanding of areas of computer science at the Merit level you will need to:

• 
  explain how key algorithms or techniques are applied in selected areas
  
• 
  explain examples of practical applications of selected areas to demonstrate the use of key algorithms and/or techniques from these areas.
  

To demonstrate comprehensive understanding of areas of computer science at the Excellence level you will need to:

• 
  discuss examples of practical applications of selected areas to demonstrate the use of key algorithms and/or techniques from these areas
  
• 
  evaluate the effectiveness of algorithms, techniques, or applications from selected areas.
  

Possible Activities

The activities below are activities which generate specific content that you can use to develop your report. For example, if you were to Review what went wrong in a software disaster (see activity 3 below) you could generate information related to several parts of the report.

1. 
   Interview practicing software engineer(s) about the techniques they use and the problems they encounter in their job, contrasting a plan-driven methodology with an agile methodology.
   
2. 
   Play the SimSE game (http://www.ics.uci.edu/~emilyo/SimSE/) using the waterfall and Extreme Programming approaches, and report on what happened during the experience, contrasting the two approaches.
   
3. 
   Review what went wrong in a software disaster.
   
4. 
   Report on the viability of a career in software engineering (eg demand for software engineers).
   
5. 
   Report on an experience doing a team activity that highlights the importance of communication and planning in a team working to create a product within constraints (eg building a house of cards or completing the 48-hour film competition), carefully following the role of each person, how they knew what to do, how effective the allocation of work was, and whether the desired outcome was achieved.
   

Essential documents

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