|Teaching and Learning Forum 2007 [ Refereed papers ]
Stanislaw Paul Maj and Bao Tran
School of Computer and Information Science
Edith Cowan University
There are different, but equally valid approaches to teaching network technology. One active learning approach, the Cisco Network Academy Program (CNAP), is based on employer expectations and hence teaches students to design and configure networks. A network typically consists of different technologies each running a number of different protocols. An extensive analysis of the CNAP curriculum found that it lacked a coherent pedagogical model of devices and protocols. Without such a model students will typically develop their own model which is likely to be incomplete, inconsistent and incorrect. In an attempt to address this problem State Model Diagrams were developed. State Model Diagrams allow networking concepts and device configuration to be taught using a single common template. This is important because students do not have to learn a new model for each network device and associated protocols. In effect new knowledge reinforces existing knowledge. State Model Diagrams have been successfully used as the pedagogical foundation of network curriculum and the results evaluated. One objective of education is to prepare students for employment. In this context employer expectations are that students can be immediately effective. This paper evaluates State Model Diagrams as a method of teaching the higher order learning levels associated with practicing professionals.
Among the approaches towards networking curricula, one finds the more quantitative (electrical engineering) style of teaching networking versus a more software/algorithmic (computer science) approach, the more "hands-on" laboratory based approach versus the more traditional in-class lecture based approach; the bottom-up approach towards the subject matter versus a top-down approach.An alternative approach is a 'hands on' curriculum is the Cisco Network Academy Program (CNAP). The CNAP provides not only network curriculum and certification but also low cost equipment (switches, routers, wireless access points etc). The CNAP curriculum is integrated with workshops in which students must configure commercially available devices such as switches and routers. The knowledge and skills gained are directly relevant to employer expectations. Vendor based curriculum, especially within the university sector has advocates and critics (Abelman, 2000) (S.P Maj & Dharukeshwari, 2003) (Murphy, Kohli, Veal, & Maj, 2004).
There are two main problems with the CNAP curriculum. Firstly device configuration is taught primarily by means of the Command Line Interface (CLI). The CLI is a hierarchical text based interface that requires considerable expertise. Whilst the CLI is routinely used by practicing professionals it is problematic for novice students (S.P Maj, Kohli, & Murphy, 2004). Secondly, devices are considered as 'black boxes' and students are not provided with a coherent conceptual model (S.P Maj, Kohli, & Murphy, 2004). This is problematic because students are taught a number of different devices and associated protocols. According to Constructivism, an important educational theory, students construct knowledge rather than simply receiving and storing knowledge transmitted by the teacher. If students are not provided with a conceptual model they are likely to construct their own which is typically inconsistent, incomplete and incorrect. Furthermore this may inhibit future learning. The ability to recall and explain a concept does not necessarily reflect understanding, nor does it guarantee that students can apply and use the concept in a meaningful way (Julyan & Duckworth, 1996). According to Ben Ari,
The science-teaching literature shows that performance is no indication of understanding. CSE research like Madison's, which elicits the internal structures of the student, is far more helpful than research that measures performance alone and then draws conclusions on the success of a technique. A student's failure to construct a viable model is a failure of the educational process, even if the failure is not immediately apparent. (Ben-Ari, 1998)This constructivist view recognises that before learning can take place a student must actively engage with, and process, information. This processing is in the context of prior knowledge which includes any existing mental models held by the student. The Constructivist approach accepts that initial constructions of perceived information can be quite limited in breadth and depth and that subsequent building on these ideas to form higher-level conceptual structures may well require considerable effort by the learner. This conceptualisation process may be assisted by the provision of good models that form the bridge between students' existing ideas and ideas that form part of the body of knowledge being taught.
Furthermore, good mental models may assist in conceptual change but also allow the construction of richer ideas. Research conducted in science education over at least the last 25 years has demonstrated across many contexts that students' existing ideas are often firmly held and unfortunately often wrong. Indeed students' existing conceptual models may hinder further learning (Driver & Erikson, 1984).
Models can be employed as an aid to conceptual understanding. According to Thomas, "The use of diagrammatic representation provides an alternative to just offering more words which may only compound their difficulties" (Thomas, 2000).
Furthermore, Gilbert notes that,
... a model is a simplified representation of a system, which concentrates attention on specific aspects of the system, Moreover, models enable aspects of the system, i.e. objects, events, or ideas which are either complex, or on a different scale to that which is normally perceived, or abstract to be rendered either visible or more readily visible. (Gilbert, 1995).Science education makes use of models as pedagogical tools (Gilbert & Boulter, 1998; Linn & Muilenberg, 1996). Mental models provide a powerful mechanism for storing knowledge within the human mind (Norman, 1983). It has been suggested that providing an individual with a conceptual model of a system before instruction enhances user learning (Bayman & Mayer, 1984; Carroll & Mack, 1985; Moran, 1981).
Mental models need to utilise abstraction: "Schemas are conceptual structures and processes which enable human beings to store perceptual and conceptual information about the world and make interpretations of events through abstraction" (D'Andrade, 1992).
Mental models are part of our normal conceptual framework (von Glasersfeld, 1992). According to Forrester, "One does not have a city or a government, or a country in his head. One has only selected concepts and relationships, which one uses to represent the real system" (Forrester, 1971) He further states that "The mental model is fuzzy. It is incomplete. It is imprecisely stated. Furthermore, within one individual, a mental model changes with time and even during the flow of a single conversation" (Forrester, 1994).
Providing students with a suitable conceptual model, early in the learning experience, that can integrate concepts and procedural knowledge is therefore potentially important.
Within network technology education the Open Systems Interconnect (OSI) model is typically used. Whilst the OSI model provides a useful framework to categorise devices and protocols it cannot be used to provide the detail associated with device configuration. Device configuration is an essential aspect of active learning within this field.
Real world dynamic systems involve a large number of variables and interconnections. Abstraction is a technique of suppressing details and dealing with the generalised, idealised model of a system. The need of abstract models and traversing levels of abstraction are essential as complex models are used in practice. (Lee & Fishwich, 1996)The importance of abstraction as a pedagogical tool is emphasised by the ACM/IEEE Computing Curriculum 2001 identifying it as one of the twelve recurring concepts fundamental to computing,
Levels of abstraction: the nature and use of abstraction in computing; the use of abstraction in managing complexity, structuring systems, hiding details, and capturing recurring patterns; the ability to represent an entity or system by abstractions having different levels of detail and specificity. Examples include levels of hardware description, levels of specificity within an object hierarchy (Tucker et al., 1991)Models, based on abstraction, are therefore a means of controlling detail. Ideally models should be: diagrammatic, easy to use and allow hierarchical top-down decomposition to control detail. In order to address these problems identified with the Cisco curriculum State Model Diagrams (SMDs), based on the principles of abstraction, were designed (S.P Maj & Kohli, 2004). SMDs are a diagrammatic modelling method that extracts data from the text based command line interface of devices (Figure 1). It is possible, using SMDs, to explicitly show how the different devices and associate protocols interact. For example the SMD shows that PC1 has an IP address and a Medium Access Control (MAC) address. Furthermore PC1 has a gateway IP address which is the IP address of interface fa0/1 of the router. PC1 is running the Address Resolution Protocol (ARP) which automatically obtains the MAC address of the router.
Figure 1: State model diagrams.
SMDs have been used as the pedagogical foundation for all aspects of network technology curriculum - lectures, workshops and evaluation. According to Maj,
SMDs allow networking concepts and technical detail to be taught using a single common template. Technical details may be progressively included whilst maintaining conceptual integrity by means of hierarchical levelling. SMDs may therefore support student learning at both introductory and advanced levels. In effect students do not have to learn a new conceptual model; rather they can build upon and extend existing knowledge. In this context new knowledge reinforces existing knowledge (Maj & Veal, in press).SMDs have been used as the primary instructional vehicle for all lecture material. SMDs have also been used in the associated workshops in order to integrate theory with its practical implementation. Over a number of years the learning outcomes of curricula based on SMDs has been evaluated. One study, conducted during the semester and six weeks after the final examinations, suggests that SMDs significantly enhanced student learning. According to Maj,
This indicates that both groups of students learnt the required material equally well. However from the diagrams of the state model students it can be inferred that they have richer conceptual understandings and these were aligned with those of the expert. Consequently they will be more able in future learning to progress towards the end state of the expert's understandings. They are also more likely to retain learnt material as this material is linked to more and better concepts thus enhancing recall. (S.P Maj, Kohli, & Fetherston, 2005)Students studying the Cisco curriculum have also been introduced to SMDs and the results evaluated. Again according to Maj,
Students were asked to evaluate the SMDs as a method of instructional delivery via a questionnaire. From a total of 34 responses, 27 (79%) indicated that they would like the SMDs to be used as part of the normal lecture in addition to the standard CNAP (Maj & Veal, In press).SMDs have been used for all formative and summative assessments. It has been demonstrated that students have used SMDs to solve problems and also predict the correct values that should be placed in empty cells of SMD tables (Maj & Veal, in press). This suggests the application level of cognitive learning.
Many students can juggle formulae and reproduce memorised textbook knowledge while not understanding their subjects in a way that is helpful for solving real problems. (Ramsden, 1992)Large companies may well have training programs for new recruits, however within the Small to Medium Enterprise (SME) sector this may not be the case. The Dearing report noted that,
The SME sector, which we believe to be of increasing importance, needs a distinctive response from higher education institutions in terms of initial skills of graduates and consultancy support. From initial skills, SMEs told us they need graduates who can make an immediate contribution to work as soon as they arrive in the company (Dearing, 1997).Employment ready graduates may well be expected to be effective when they first enter their profession (Dunn & Carson, 1998). In this context knowledge, skills and experience gained within an educational context should have a direct relevance to the world of work. Practicing professionals have a body of knowledge and expertise that has been acquired over a number of years. In particular, practicing professionals are likely to be called upon to demonstrate higher order levels of learning. According to Bloom,
A problem in the comprehension category requires the student to know an abstraction well enough that he can correctly demonstrate its use when specifically required to do so. "Application" however, requires a step beyond this. Given a problem new to the student, he will apply the appropriate abstraction without having to be prompted as to which abstraction is correct or without having to be shown how to use it in that situation (Bloom, Engelhart, Furst, Hill, & Krathwohol, 1956).Furthermore, application is a higher order cognitive taxonomy level,
Analysis emphasises the breakdown of material into its constituent parts and detection of the relationships of the parts and of the way they are organised. It may also be directed at the techniques and devices used to convey the meaning or to establish the conclusions of a communication.Skill in analysis is therefore considered an important educational objective and one directly relevant to employer expectations.
Three students currently studying network technology curriculum based on SMDs volunteered to complete a questionnaire. All three students either had relevant commercial experience or were currently employed in IT.
All three participants were given a number of questions based on the first four cognitive domain levels - Knowledge, Comprehension, Application and Analysis (Bloom, Engelhart, Furst, Hill, & Krathwohol, 1956). The questions based on the analysis domain required the participants to analyse and compare two networks.
The results, including all verbatim student comments, were as follows
Participant # 1The participants were asked to rate, using a Likert scale (strongly agree, agree, neutral, disagreed and strongly agree), SMDs as a tool for managing networks. Two participants responded with strongly agree and the third chose the agree response.
I believe that SMD are very helpful tool to understand & trouble-shoot any network at different OSI layers. But at the same time it would be important to keep yourself accustomed to the CLI output. This is because you are trouble-shooting a problem you need understand and trace information from the CLI (THIS IS VERY CRUCIAL). SMD helps significantly to 2 people, one who is novice & other who is new to the network & has very few info about that particular network.
Participant # 3
When we talk about complex network it contain many routers, switches, PCs. If we try and draw state model for all the equipment on a complex network, practically it will be hard. If there is an easy way to draw the models, then I think it's better than command line configurations. If someone can draw SM for me, I will use these diagrams to manage my complex network.
Finally the participants were asked to rank, using a five point Likert scale (1 being the worst to 5 the best), SMDs as a teaching tool. All three participants gave SMDs a ranking of 5.
According to Bloom the taxonomy level of comprehension is demonstrated when the student knows an abstraction well enough that they can use it to solve a problem. The higher order level of application is when a student is presented with a new type of problem and then, without prompting, correctly applies an appropriate abstraction. Significantly in one of these exercises the participants were given a problem new to them and allowed to use whatever means to solve it. All participants were given access to Ciscoworks, a standard, commercially available network management tool. None of the participants used this tool or any others; all of them elected to use SMDs to solve the problem.
The analysis cognitive domain level may be divided into three levels: elements; relationships and organisational principles. In order to determine achievement at this level the participants were provided with a network and asked to identify the slowest link i.e. the bandwidth bottleneck. An educational objective associated with the analysis of elements is the ability to recognise un-stated assumptions. In this case the participants were provided with the type of communication links but not their bandwidth performance. Furthermore, in order to determine any bandwidth bottleneck the participants would need to determine how the different communication links interact - an educational objective associated with relationships.
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|Authors: Dr Stanislaw Paul Maj is an associate professor in the School of Computer and Information Science at Edith Cowan University. In 2006 he won a Carrick Australian Award for University Teaching Citation Award for The development of "world class" curriculum and the design and implementation of associated "world class" network teaching laboratories.
Bao Tran is a Research Support Officer in the School of Computer and Information Science at Edith Cowan University. Currently he is doing research on network education and management strategies.
Postal: School of Computer and Information Science, Edith Cowan University, Bradford Street, Mount Lawley WA 6050, Australia. Email: firstname.lastname@example.org, email@example.com
Please cite as: Maj, S. P. & Tran, B. (2007). Network technology education: A novel pedagogical model for novices and practising professionals. In Student engagement. Proceedings of the 16th Annual Teaching Learning Forum, 30-31 January 2007. Perth: The University of Western Australia. http://lsn.curtin.edu.au/tlf/tlf2007/refereed/maj.html
Copyright 2007 Stanislaw Paul Maj and Bao Tran. The authors assign to the TL Forum and not for profit educational institutions a non-exclusive licence to reproduce this article for personal use or for institutional teaching and learning purposes, in any format (including website mirrors), provided that the article is used and cited in accordance with the usual academic conventions.