Guidelines for Distance Training with TANGO Interactive

For Students

• TANGO-delivered classes are subject to technical problems with the network and other outside factors as well as the occasional glitch in TANGO itself. TANGO glitches can usually be remedied fairly quickly and easily with the help of experienced support staff.  Outside factors, on the other hand, may leave the instructor and support staff as frustrated as you.
• We plan to begin controlled experiments with "direct to the desktop" delivery (instead of to a local training room) in the near future.  Interested students should be aware that this will require some preparatory work with support staff (local or remote).  The goal is not to discourage direct to the desktop delivery, but to do it in a controlled environment in order to help insure its success, and to better understand the issues that will come with wider deployment.
• While many people express an interest in "direct to the desktop" delivery instead of having to go to a centralized training room, even local, it is worth noting that others have expressed a preference to get away from the distractions of one's office in order to really concentrate on the training.

For Instructors

• Although you may not be accustomed to practicing delivery of regular classes, it is very important to practice the delivery of TANGO-based classes until you are thoroughly comfortable with the tools.  Some of your practice sessions should include at least one TANGO recipient to help point out common mistakes, such as pointing with your hand instead of using the mouse (for tools with a shared pointer display) or describing where you want to point (in general).
• Expect TANGO-based classes to move a little slower than local classes -- words must replace gestures and body language that would suffice in a local class, and things like student questions can be somewhat more cumbersome.
• The audio codec typically used in TANGO (GSM) provide roughly telephone-quality sound -- not broadcast quality. You should be careful to speak clearly and perhaps a little more slowly than usual for face-to-face teaching to insure that you are understood by the remote students.
• Before setting up a TANGO-based class, give careful consideration to the content of your class, and be sure that TANGO will support your needs, and provide a way to share all of the content you plan on using.  If you're not sure, talk to the TANGO developers.
• Our experience is that the attention of remote students wanders a little more easily than in face-to-face classes. Probably because there is less stimulus, and less of a sense of connection with the instructor, so we suggest...
• Don't be afraid to make course materials colorful and visually interesting.
• Try to make the class a little more interactive than you would a regular face-to-face class to help hold student interest/attention.
• If there is a support person or technician available at the delivery site, don't be afraid to make use of them if it will make you more comfortable. They might be able to help monitor student questions on chat or assist in other ways. Talk to them before the class to plan roles, signals, etc.

For Delivery and Recipient Sites

Hardware Requirements/Recommendations

• We recommend the use of two separate machines to deliver classes where possible, one handling TANGO and the course materials (shared browser or WebWisdom), and the other handling audio and video. This is because the audio and video codecs can require significant amounts of CPU time, and the two system configuration prevents this from adversely impacting the rest of TANGO.
• In classroom environments beware of the microphones (and speakers) often built into computer systems.  Mics are typically omnidirectional -- they pick up sound from all directions.  In the distance education setting, this makes them prone to producing feedback, as they pickup the output of a speaker and feed it back into the audio system.  Cheap, lower sensitivity mics with more selective pickup patterns can help reduce feedback problems.  Headsets with boom microphones are another alternative.
• A wireless lapel microphone can give instructors a little more mobility without sacrificing audio quality. A wireless handheld mic can be helpful in allowing students to ask questions.
• Here is a list of audio and video hardware that we have used successfully with TANGO/BuenaVista. This is not an exclusive list!
• Video
• Winnov Videum Conference Pro card and camera (Windows 95/98/NT)
• Intel Smart Video Recorder III with any compatible camera (Windows 95/98/NT)
• Panasonic EggCam
• SGI O2 standard camera
• Audio
• SoundBlaster64 audio card with full-duplex driver
• Parrot ST Gold headphones
• VXI boom mic systems
• Please see the BuenaVista Manual for detailed guidelines for setting up audio and video.
• A good, well-tested audio setup is crucial to a successful class. Feedback, in particular, can be not only annoying but can also damage ears and equipment.
• Because it has to send so many a/v streams, the instructor's workstation generally has the greatest demand placed on it of any computer involved in the training. Give some thought to the available bandwidth (probably 10 MB/s ethernet), and CPU power (for the a/v codecs) in planning for the class.

Network Considerations

• Some thought and testing should be given to the quality of the network between all of the sites involved (primarily the path between the delivery site and each of the recipient sites).  We have found the DREN to generally provide good quality connections, but the commercial Internet can be highly variable.  If network quality is questionable or highly variable, it might be advisable to try to schedule class to avoid the highest network traffice periods (typically late afternoon on the east coast).
• In cases where the network quality is questionable or unreliable, using speaker phones (on a conference call, if there are multiple recipient sites) can be a useful alternative to using TANGO's BuenaVista to transmit audio, especially when coupled with proxy web servers at recipient sites to make the best use of the available network capability. Audio transmission is the most susceptible to network quality.
• Minimal bandwidth requirements (per stream) for TANGO are as follows: Audio (GSM) 13 kb/s, video (H.263) 15 kb/s, courseware 120 kb/s. The number of streams required during a training is varies greatly depending on details of the setup, which are often at least partly under the control of local training room staff.
  • Audio: The instructor's workstation must send one stream to each BV audio client. If students are listening individually on headphones, there would be one client per student. If sites are broadcasting audio to the training room using speakers, there would be one client per site. Each open student microphone which might be used for asking questions will also send a stream to all of the other BV audio clients. Since open mics tend to pick up and transmit environmental noise, we strongly recommend that student mics be used in a "click to talk" mode. Note that a multicast version of BuenaVista is under development, which will eliminate the stream multiplication caused be the current point-to-point architecture, but will require a working multicast backbone between sites.
  • Video: This is currently transmitted "point-to-point", just like the audio, so the number of streams is determined the same way. In TANGO trainings, video usually presents a "talking head", not actually conveying the course materials. Therefore, it is possible to get away with many fewer streams. Instead of separate streams of individual faces, the instructor would probably rather see an overview of the entire classroom. While courseware may not work so well on a centralized display at recipient sites, a video of the instructor probably will (as opposed to each student running their own video client).
  • Courseware: This is a web server delivering slides/pages to student browsers. In general, one stream is required to each receiving workstation. This can be reduced to one per site through the use of proxy web servers at recipient sites (see below). It can also be reduced by using a centralized large display at recipient sites, however these may have a less-than-acceptable image quality for some types of course material.
• Make sure each site's network connection are sufficient to handle necessary traffic. Likewise, check how the sites are connected to each other and especially to the delivery site. For example, a T-1 line (1.5 Mb/s) can carry at most 100 a/v streams, or about 10 simultaneous pages of courseware in the absence of any other traffic.

Software Requirements/Recommendations

• To reduce network bandwidth requirements, we recommend that all recipient sites setup a proxy web server with caching capability (i.e. Netscape Proxy Server; we would welcome reports of experience with others) and configure their browsers to use it.  During a class, each page of web-based course material will be downloaded to every participating browser, resulting in many simultaneous "hits" on the web server providing the class materials, and each request consuming bandwidth (a simple 20 kB GIF image distributed to 50 clients requires that the web server send 1 MB of data in total).  Properly configured, all requests at a given site can instead be handled by a local proxy server, reducing the demand on the class web server to one copy per site instead of one per client.
• If possible, all sites should use the same version of Netscape Navigator.  This helps to avoid "site-specific" problems caused by TANGO interacting with bugs specific to a particular version of Navigator.
• Pre-class testing should exercise all TANGO tools that will be used during class delivery to insure that they work correctly at all sites.  This is all the more important if all sites are not using the same version of Netscape Navigator.
• Use separate chat tools for communications between the instructor and students (i.e. questions), and among the support personnel.
• Use a robust HTTP server to provide the course materials.  Our experience suggests that some servers (in particular Netscape FastTrack normally provided on SGI boxes and Microsoft Peer Web Server) will hang easily when subjected to the demands of a typical class.  We recommend the free HTTP server Apache as a more robust alternative.

Other Guidelines

• The delivery site should try to arrange the instructor workstation and camera(s) so that the instructor can easily shift the focus of their attention between the screen, the local class, or the remote classes (camera) without having to completely change position.

General Comments

• Agree in advance on the web site and TANGO server that will be used to start TANGO for the class (and all tests). Using the same web site will help insure that everyone is using the same version of all Java-based TANGO tools, and of course everyone must connect to the same TANGO server. TANGO itself requires very little bandwidth (as opposed to the audio, video, and courseware streams), and it makes little practical difference which TANGO server is used.
• Testing in advance of the the actual class is very important to its success. The amount of testing needed depends on the novelty of the particular event planned, and on the level of experience of the participating sites. Care should be taken to exercise all of the tools (within TANGO or outside of it) that will be used during the class to check for any version conflicts that might cause problems. The audio and video setup at all sites should also be tested. Testing should be done far enough in advance to allow time to fix or work around problems that might be uncovered, but close enough that the configuration will not "decay" between the test and the actual event. Instructor practice to familiarize themselves with TANGO is a separate matter, but it can be useful to have the instructor "drive" the test sessions too -- they should be the most familiar with what tools they intend to use, and how they'll use them.
• Scheduling tests and classes at multiple sites can sometimes prove to be more trouble than actually delivering the class! Unfortunately, TANGO doesn't have a solution for this (yet?). Don't give up too early.
• In all discussions involving multiple sites, be sure to make clear which time zone is intended when setting schedules.
• Responses so far are mixed on the importance of video to the distance learning process. Since the courseware is assumed to be web-based, video in this case is typically the instructor ("talking head") and/or an overview of the recipient classroom.  We have conducted many successful classes without video in either direction, but some have commented that the video helps make the connection between instructor and students, and may increase student attention levels.
• Please see http://www.osc.edu/~troy/tango/ for a student-oriented introduction to TANGO Interactive.