This material is a collection of tutorials, presentations, glossaries and other content in the area of data networking and computer communications. The collection has been organized by Debby Koren, but others have contributed the content. The site is hosted by RAD, a network equipment company. One set of tutorials has been prepared by students in a networking course and offer the reader introductory to moderately in-depth coverage of a broad array of topics. These cover a broad range of topics including general networking principles, network technologies, core protocols used in the Internet, and applications. Most of these tutorials introduce some topic and provide a bit of fun through a quiz or game. Some of the tutorials include animations or other demonstrations related to the topic. The tutorials are intended to introduce and illustrate key concepts and terminology. There are also a set of audio tutorials provided by RAD. Also included are glossaries covering terms related to networking in general and Asynchronous Transfer Mode (ATM) specifically.
Upon completion of a given module, students should be able to:
Discuss the need for and applications of the technology;
Define the basic terms related to the tutorial topic;
Describe the operation of the protocol or technology; and
Describe factors that affect performance or otherwise alter operation.
Some modules are more complete than others with respect to these goals.
Target Student Population:
The material is relevant to students studying networking or telecommunications in a discipline such as electrical engineering,
computer engineering, computer science, information systems, or information technology. The material is mostly relevant to upper-division undergraduate students, although it would be also be accessible to lower-division undergraduate students and students in a two-year technology degree program. Some of the tutorials on more advanced topics would be of interest to first-year graduate students as an introduction to the topic. Practitioners in information technology, in particular those in the networking area, will also benefit from this material.
Prerequisite Knowledge or Skills:
The tutorials assume some basic knowledge of computer systems, such as data representation. The collection includes tutorials that introduce basic networking concepts. These concepts should be mastered before moving on to other tutorials in other specific areas.
Type of Material:
The components of this collection contain a variety of different types of material, including simulations (e.g., simulations of TCP throughput with adjustable data rates, latency, and error rates), animations (e.g., of packet transfers), tutorials (on almost all topics), quizzes (often in the form of a game), lectures, and reference material. Note that not all topics are supported by all types of materials.
The nature of the material in the collection varies, so it could be used in different ways. The most appropriate use for most of the material is for at-home study by an individual. Some of the simulations and animations could be used in the classroom to illustrate concepts. The material is organized into types of tutorials, but there is not overarching content that unifies the topics, thus a textbook or comprehensive set of notes would be needed in addition to this collection. An instructor could assign specific topics to be studied using the collection. In addition to standard descriptive questions, a homework assignment might require students to use simulations to, for example, plot the throughput of TCP for different bandwidth-delay products and to then discuss the results and speculate on methods that could be used to increase throughput. The quizzes with many of the tutorials are a good way for students to review the material. Overall, this site is useful as supporting material for a first course in network architectures and protocols, as well as a reference for students interested in networking.
The various animations, games, etc. worked best with Microsoft Internet Explorer (tested with version 6). There were problems using Mozilla Firefox (version 1.0). A number of plug-ins and other capabilities are needed for some tutorials,
Evaluation and Observation
On the whole, the quality of the content is very good.
Most tutorials are complete and can be useful for the intended audience.
Tutorials are provided for a broad array of topics in computer networking. New (e.g., IEEE 802.16) as well as legacy (e.g., ISDN) technologies are represented. For the tutorials that I checked, content was accurate.
There are few minor factual errors in some modules. For example, in the IEEE 802..15/16 module, it is stated that the "principal characteristic of an ad hoc network is its limited temporal and spatial extent," when the "lack of shared infrastructure such as access points" would be a better statement about the principle characteristic of an ad hoc network. As another example, it is a bit sloppy to call IEEE 802.11 "wireless Ethernet" as a different medium access control (MAC) protocol is used, not just a different physical (PHY) layer.
Some of the animations, such as the videoconferencing animation in the H.323 tutorial, are cute but not informative.
Since each tutorial was created by a different group of authors, they are somewhat uneven in the quality of the writing, depth of coverage, and supporting visual aids (such as animations).
Potential Effectiveness as a Teaching Tool
A number of the animations and simulations effectively provide insight a number of important concepts.
The tutorials provide an effective way to introduce a variety of networking-related subjects and would be a good complement to a standard textbook.
Information is depicted using text, graphics, and, in some tutorials, animations and simulations to convey concepts.
The quizzes in many of the tutorials provide a good way for students to review the material.
The tutorials contain a lot of text that may not be very engaging to students, especially if a large number of the tutorials are used. While there are some graphics, animations, and simulations, these are not substantially present in most tutorials.
Most of the quizzes just indicate a score or a "right" or "wrong" response. Some feedback about why an answer is right or wrong would be useful in helping students learn the material.
There are other, perhaps better, simulations, animations, etc. for some topics. For example, the RIR application does not appear to be substantially different than some other WHO-IS applications.
Ease of Use for Both Students and Faculty
The overall collection is well organized. Topics are sorted into different categories to make it easy to find tutorials of interest.
Most of the modules are clear, easy to use, work properly.
Breadth of topics treated.
The backgrounds in some tutorials are too dark for the font color or have a pattern that makes it difficult to read the text. Most tutorials do not have this problem, though.
Different tutorials have different characteristics for "look and feel." Use of a common, well-designed template would have improved the ease of use.
The UDP Information Center tutorial has a broken graphic (the browser cannot findhttp://www2.rad.com/networks/2004/udp/images%5Cdemux.gif).
The maze game in the Networks-Interactive Games module did not work. The browser reported "'Applet notinited' ... 'Loading Java applet failed'." Other Java applets did work.
Something strange was happening with the Audio Presentations. The audio would not work on my computer. The system reported "no audio device available," even though this computer does have audio support and other audio content works.
Some of the sites are not easy to navigate,
and there is often no direct way to return to the main site.
Other Issues and Comments:
Overall, there is a lot of very good information in this collection. Several of the animations and simulations are very useful for learning. Some of the tutorials are really outstanding, However, some weaker tutorials detract from the overall quality.