Evaluation of Marratech video-enhanced collaboration (original) (raw)

This page is an online version of the final report generated by the Kan-ed project to evaluate video-enhanced collaboration as a potential Kan-ed service.

The project

Project scope:

"Conduct tests, and encourage testing by other groups, of the Marratech video conferencing system in order to render a recommendation for deploying a video-enhanced collaboration service within Kan-ed, and assess the suitability of the Marratech collaboration product for such services.

Note that this project does NOT extend to deployment of a productional service, but only to the assessment of the desirability of such a service."

Major project activities

As part of this project Kan-ed:

A review of the video tool landscape

To establish a role for "video-enhanced collaboration" tools, it is necessary to review alternative communications tools. One might argue that the major competitor is telephone conferencing, but this page will consider only selected video conferencing configurations that are either common in the Kan-ed community or germane to this project and/or this talk.

They are:

To understand these tools, one must first understand some of the technical components of the process of converting visual and auditory information into a form suitable for manipulation by computers and transmission among computers.

For a quick review of networked video basics, seeNotes on video compression and compression standards

Table of Contents

So...here's an outline of this talk:

The Access Grid

The Access Grid was developed by the Argonne National Laboratory Futures Lab during the late 90s for use over Internet2 and other networks supporting Multicast.

The "design point" for the Access Grid was "small group conferencing", though it was frequently used for auditorium-sized groups, using open-source components whenever possible.

Feature set:

Configurations of recent instantiations:

This system employs H.261 compression via the open-source program called "vic" and H.721 audio compression via "rat", VNC for application sharing, and dPPT for sharing PowerPoint slidesets (at full SVGA resolution).

vic and rat use RTP to exchange data.

The Grid can pretty effectively accommodate conferences of up to about 10 sites (40 cameras) connected simultaneously.

H.323

H.323 is an umbrella recommendation from the ITU-T, that defines protocols to provide audio-visual communication sessions on any packet network. H.323 references:

Also, H.323 requires the presence of H.261 and G.711, but allows other codecs such as H.263 and G.723. (Note that H.261 will provide 352x288 resolution at best, and that most H.323 interactions operate at this resolution.)

In addition, H.323 references (but does not require use of) the T.120 suite of protocols that define capabilities that may be used to build collaboration applications (control of multimember groups, simultaneous data transfer among members, transmission of whiteboard information, application sharing, etc.).

Finally, H.323 includes specs for

Point-to-point conferencing using H.323

There exist many H.323 clients that can engage in point-to-point conferences.

And there are quite a few vendors of such products.

The best known software client is NetMeeting.

The best known hardware manufacturer is PolyCom, which makes a whole line of H.323 devices.

Theoretically, H.323 clients from different manufacturers should be able to interoperate flawlessly. That is one of the advantages power of the "standards-based model."

Multipoint conferencing using H.323

H.323 defines a multipoint control facility that will allow multiple clients to interact with one another.

Several vendors supply such Multipoint Control Units.

Within a multi-point conference users may not be able to see all participants simultaneously. Typically the MCU will be configured to show users whoever spoke last or partition the screen showing one participant per partition. (This last approach must sacrifice video resolution as it forces multiple images into a single image.

PolyCom also makes units that combine the function of a client and a small MCU. For example, there are clients that can connect with three remote sites simultaneously and share images among all 4 communicating sites. (Note that these units usually reduce the quality of the bitstream to each remote site to be able to process multiple streams.)

The Cytek/NCKEN/KDLC IDL model

This model uses multiple point-to-point H.323 connections to achieve multipoint connectivity.

Each classroom is configured with 3 H.323 codecs connected directly to up to 3 other classrooms simultaneously. (This is sometimes referred to as "full mesh" connectivity.)

Configuration:

The current version of the IDL model offers several valuable capabilities:

full-screen views

Each classroom sees each other classroom as a full-screen image (at 352x288), rather than as part of an image on a partitioned screen.

continuous presence

Each classroom sees each other classroom continuously; there is no "screen switching".

remote camera control

The instructor can control the cameras in remote classrooms on-the-fly.

simple instructor controls

Instructors control the system using a very simple interface composed of either mechanical buttons or a computer touch-screen.

These systems typically employ a single 768 Kbps connection to connecteach pair of H.323 codecs, so that individual schools need only 3Mbps connections to Kan-ed to conduct 4-way classes.

H.263 at 352x288 at this bandwidth is probably "approaching" VCR quality.

The feature set of this model was arrived at through community discussion, experimentation, and systematic comparisons weighed against the economic and technical constraints then facing the community of potential users.

Note that some nodes have the ability to share PowerPoint slidesets at high resolution, and that some nodes use scan converters to display PPT, MS-Word, etc. (Marratech might offer an assist here.)

The "Western Kansas" IDL model

This model is configured like the Cytek IDL model, except for the use of MPEG-2 codecs which:

MPEG-2 quality at 720x480 (or so) at this bandwidth approaches or surpasses Satellite and DVD quality?

The Western Kansas consortia have developed "gateways" that allow their sites to interoperate with sites using the Cytek IDL equipment, and they also operate their own Renovo schedulers.

The Marratech version of "video-enhanced collaboration"

The Marratech system is quite similar to the Access Grid. In fact, it is interoperable with vic within a Multicast-enabled network, but is NOT H.323-compliant.

Feature set:

These features are available within a single window ("flexible" mode), and within multiple, independent windows ("expert" mode).

The Marratech client almost always presents a coherrent frame, and the amage stream adapts well to limited and/or congested bandwidth. However, partly as a result, video is seldom up to 25 fps, and H.261 image quality is perceivably lower than H.263, as implemented by PolyCom using 768 Kbps within IDL nodes.

Marratech was designed for desktop use, and, when used as such, requires the following configuration:

Note that PowerPoint and MS-Word are NOT required on remote systems to share PowerPoint and MS-Word documents. A "rendering" of each page is shared.

To use the product in a conference room environment one would usually require some additional components (looking suspiciously similar to an Access Grid configuration):

Marratech clients will run on Macs, PCs and Linux platforms, and generally install easily and run reliably.

The Marratech Server

Licensing rests upon a model that recognizes users and user groups, as well as virtual meeting rooms and "auditoria."

The server allows administrators to define:

Each (master) server is configured with a license for some number of seats and some number of auditoria.

Administrators may define rooms and auditoria ad lib within the license limitations.

This can cause problems when multiple rooms are defined.

The server can be configured to use an LDAP server for authentication.

The "server" can actually be configured as a collection of servers, a "master" server and up to 5 or so "slave" servers. A set of such servers can relay information among one another in the most dynamically economical topology.

Initial connections are made to the master server, which deals with license management, and the system as a whole decides to which server each client should actually connect for data transfer.

Servers can communicate with clients (and other servers) using Multicast if it is available, and otherwise via unicast. (If Multicast is available to all participants, the server does nothing but license management.)

The server offers no scheduling capability.

Responses to the questionnaire

The Kan-ed Video Services Workgroup worked with Kan-ed staff to develop a simple web-based questionnaire to help assess users' experience with the Marratech client and Marratech-based conferencing. Here are tabulated responses to every questionnaire item:

I have used Marratech:

I have had some training on either Marratech or another desktop videoconferencing system.

Using Marratech I have participated in:

It was easy to download the Marratech software.

It was easy to hook up the audio and video components.

It was easy to find and enter the conference.

I would be pleased to use Marratech again.

If it were available, I would consider making Marratech a standard part of my professional communication

Incompatibility with the H.323 video standard (i.e., PolyCom video conferencing units) is a problem for me.

If it were available, Marratech would save me, personally, in travel time:

I estimate that I would use such a service:

Comments from the questionnaire

Here is a list of the comments contributed by questionnaire respondents:

Log info

Within the last 5 weeks (4-12 to 5-18) there were:

Criteria for consideration of a new service

Some social considerations that may affect usage rates

Video conferences support only a portion of the range of expressiveness supported by face-to-face meetings due to:

There exist rituals and habits associated with face-to-face meetings that help provide structure, define roles, and reinforce group cohesion:

These factors exert idiosyncratic effects upon individul participants and groups in the areas of:

Note that people display a great diversity in interactive habits and styles and different kinds of conferences favor different behaviors. For example, some people are quite sensitive to correspondent feedback; others are less so, and such sensitivity will have a different impact as practiced by a teacher or a student, a boss or an employee, etc.

Such sensitivity will also be more or less affected by the characteristics of communications channels available during a teleconference.

(One can imagine categorization schemes that describe effective behaviors for persons playing various roles in various types of conferences, along with a set of dimensions that could be used to describe participant habits and preferences, that could be combined to estimate the impact of video conferencing technology on individual effectiveness in different types of conferences.)

The effects and uses of physical proximity (and variations thereof) in communications are quite varied, and probably not understood well enough to evaluate their absence in video conferencing.

Some ways to reduce the negative effects and limitations imposed by this technology:

Recommendations

Marratech appears to satisfy each of the criteria for establishing a new service, although cost-effectiveness will depend on actual use, which has been lower than expected, and reliability will be a function of network connectivity and end-user competencies.

Exactly what drives user satisfaction with and willingness to use such tools is not yet understood.

Convert the current leasing agreement to a server purchase.

Continue to offer use of AuditoriumOne and the 15 seats currently in place to any Kan-ed member institution.

Discuss and choose one of the following three options (or some variation thereupon):

Develop a hands-on training program and take it on the road. Include material on managing social issues.

Arrange for continuous technical assistance through NOC staff logged into a "TestRoom" and available via phone.

Acquire a provider for SIP-initiated connectivity between Marratech conference rooms and dial-in users.

Acquire and install the H.323 gateway when it becomes available.

Continue to investigate scheduling options, and implement some form of scheduling interface as soon as possible. Continue to investigate authentication options. Using the Kan-ed Desktop authentication data for Marratech authentication MIGHT be useful, but this service should NOT be integrated with the Desktop.

Even when augmented for use in a group setting, Marratech is an inferior technology for (K-12) classroom instruction, although use ancillary to existing IDL nodes may prove fruitful, and use as a conferencing tool for collaborating with remote students also seems to hold some promise.

This platform is probably adequate for many adult students taking short-term workshops, not requiring "sensitive" social interactions.

Additional information

Here are some documents related to the project and use of the server:

For more information please contact Michael Grobe at 785-817-2992 ormgrobe@ksbor.org.

Document last modified: Monday, 27-Jun-2005 17:28:28 PDT

| 1000 SW Jackson, Suite 510 Topeka, Kansas 66612 785-296-0843 phone 785-296-7052 fax | | | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | |