FAQs

A: Currently, the only supplier of off-the-shelf Access Grid nodes that we know is IOCOM Communications Inc. We have had contacts with a couple of other companies who are interested in getting into the field, so this situation may change shortly. Another option is to build your own node. Documentation on how to do this is available at http://www.accessgrid.org/agdp/guide/building-an-access-grid-node.html. If you need any more information we are able to offer advice on procurement and configuration matters.

Q2: How much bandwidth is required for an AG node?

A: 1Gbps bandwidth is ideal, 100Mbps dedicated bandwidth will probably suit most sites and the absolute minimum is 10Mbps bandwidth dedicated. If you look at the math each AG node sends out around 1.2Mbps (256Kbps for each video stream; 128Kbps for an audio stream). Therefore, in a meeting involving seven AG nodes, each node will receive around 8-9Mbps (6 remote sites X 1.2Mbps) which applies whether sites connect via a unicast bridge or multicast.

Reasons to use more than 10Mbps are simple, firstly you'll be lucky if you can utilise this bandwith efficiently enough to use all 10Mbps of theoretical bandwidth. Remember that many AG meetings involve more than seven nodes. Secondly, if you need to download files, e.g. a PDF document for discussion during the AG meeting you need spare capacity for this. Thirdly, there may be more than just video and audio being shared during the meeting; if there was a shared visualization taking place, then this could use a considerable amount of bandwidth. Fourthly, developments are underway to improve video and audio quality across the AG which are bound to necessitate increased bandwidth.

Q3: Is it possible to buy IOCOM client software?

A: Yes. IOCOM provides software which runs on a single Windows machine for 1 camera on a client desktop up to 4 cameras in a client room. A special deal has been negotiated with IOCOM for the desktop 1 camera software and a subsequent 1 year support package for Access Grid-registered users. If you want to take advantage of this offer, please contact the vtas@ja.net for further information and we will forward your details to IOCOM.

For existing AG studios, IOCOM offers software only licenses but they are not part of this special price. Also, note that the IOCOM software only runs on a single Windows machine, which means that for AG studios with four cameras, you will need a quad video capture card because most motherboards do not have enough PCI slots to hold four single cards. If you want to enquire about purchasing IOCOM software, please contact vtas@ja.net and we will forward your details to IOCOM.

Finally, IOCOM does offer many turnkey and custom hardware/software solutions, providing discounted pricing for educational institutions.

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Q4: Which video capture cards are recommended for an AG node?

A: The Videoconferencing Technology Advisory Service (VTAS) is planning a survey of video capture cards and other hardware for AG nodes. Until this is done, we suggest you research the AG-Tech mailing list archives, which is a list for open technical discussions regarding AG technology.

Q5: How can I ensure security on the Access Grid?

A: To secure sessions on the Access Grid we encrypt the media streams (VIC and RAT in the open source Access Grid client or the IOCOM client media software). The encryption key can be any string of characters (you may have been e-mailed this key when booking a session through the Access Grid Booking Service). Note: distributing the key using e-mail or telephone may not be completely secure because both methods are vulnerable to eavesdroppers. Depending on why you need a secure meeting, this may not worry you. The method of securing sessions depends on which of these software clients you are using:

To secure sessions on the open source Access Grid toolkit, encrypt the media streams using vic and rat. For a printable explanation with images click here or view the flash tutorial on Securing Meetings using AG Toolkit.

For a brief explanation, please read the following: in RAT, press Options.../Security, enter your key in the box provided, click the check box, and press Apply. In VIC, press Menu, click with your mouse in the box marked Key: (ignore the fact that this is greyed out), enter your key, and press Enter (note that you cannot click the check box, but this will be enabled after you press Enter). You need to do this for every VIC window, there will be one for each camera you have in your node and one used to receive video.

For IOCOM clients, a dialog box appears that asks whether you were supplied with an encryption key for the meeting. In this case, press \'Yes\' and enter the key into the box provided.

Security for applications beyond video and audio is beyond the scope of this FAQ.

If you have any further questions on this issue, please talk to us.

Q6: My IG Pix client (receiving) session keep works OK for a few slides then stops updating when the presenter is changing slides. How can I resolve this?

A: This issue is caused by your Internet Explorer settings. The solution is to go to the menu item Tools\Internet Options\General\Browsing History\Settings where you need to select the radio button Every visit to the webpages should make sure that IG Pix updates properly.

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Q7: How do I set up Jabber?

A: ANL currently run the main Access Grid Jabber server. Instructions for using the ANL jabber server are available from:
http://www-unix.mcs.anl.gov/fl/research/accessgrid/software/jabber.html

Q8: How do I connect to a Jabber Session using PSI?

A: To connect to a Jabber Session using PSI:

Start PSI
Select the profile created above and click on "Open". The PSI main window will appear.
At the bottom of the PSI main window, there is a star and the word "Offline". Select this button and Select "Online". You will now connect to the server.
Next to the button that now has a yellow star and is title "Online" is a second button (known as the Psi button). Select this button and select "Service Discovery" from the list that appears.
The PSI "Service Discovery" window now lists all text conversations. Clicking on the plus next to "AG Text Chats" lists all the current rooms on the ANL server.
To enter a room, double click on the room. In the window that appears, type in a nickname and select "Join".
To create a new room, double click on "AG Text Chats" and type in the name of the room and a nickname and select "Join".

Q9: My audio quality is not very good. Is there any documentation that may help me?

A: Yes, have a look at the following webpages:

http://www.accessgrid.org/agdp/tutorial/audio-troubleshooting.html

There\'s also documentation on setting up and configuring the APWare and GWare software for ClearOne echo cancellation systems:

Q10: What ports do I need to free up on my firewall for an Access Grid session?

A: We've created a Port Table giving details of the port useage for the Access Grid servers. The webpage gives details needed for network administrators to free ports for users of AGToolkit and IOCOM whether bridged or unbridged. Please note that these are the settings for connecting through the Access Grid servers; other servers may have different port settings.

Q11: Which audio and video codecs are in use on the Access Grid?

A: In the Access Grid, a codec (COder-DECoder) deals with the transformation of data signals, enabling users to see and hear others at different sites. Codecs are contained within the audio and video tools used by open source and IOCOM Access Grid clients. There are specific codecs in use for both audio and video and these must be compatible at different sites for everyone to be able to see and hear everyone else.

Currently, the only video codec that is compatible with both IOCOM and AGToolkit is H.261. However, the IG2 IOCOM software is capable of using H.264, which offers higher quality video at an equivalent data transfer rate, but uses more processing power. The open source Access Grid toolkit video client, VIC, is currently only capable of using H.261; this means that in a session with both IG2 and AGToolkit clients, IG2 users must use H.261 to enable VIC clients to see all video streams. (Note: the SUMOVER project at UCL is working to develop VIC to use H.264.)

If you are using AGToolkit, then the audio client RAT is set to use the audio codec Linear16 16Khz mono by default but is compatible with the G.711 standard. If you are using an IOCOM client, then the audio codec transmitted is the G.711 open standard which can be set for 8KHz (64Kbs of bandwidth) or 16KHz (128 Kbs of bandwidth) but can also seamlessly receive Linear16 audio streams. Therefore, open source and IOCOM users do not need to make any audio adjustments when joining a conference to hear and transmit to each other. The use of different audio codecs used by RAT is discussed in this thread on AG-TECH.

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Q12: Other than in meeting rooms where else can I use AG i.e. on a workstation from home?

A: When it was invented in 1997, the term "Access Grid" originally referred to a concept that supports effective group-to-group collaboration. This was the reason for incorporation into the Access Grid design of multiple cameras, projectors, microphones, etc., as well as collaborative software. However, the Access Grid does not have to be deployed simply in meeting rooms and can be used in a variety of contexts. Below is a brief description of some of the issues that may be encountered when deploying Access Grid outside of the typical meeting room scenario. This FAQ is, of course, no substitute for contacting the support centre for advice on your particular situation.

At a Workstation: It is possible to join Access Grid meetings from software installed on a workstation together with webcam and microphone headset. What sets Access Grid apart from other collaboration solutions is its focus on human factors (i.e. non-verbal cues, large displays and excellent audio). These factors deteriorate significantly when using Access Grid software from a workstation and it is inferior to the normal Access Grid experience both for the user and for others in the meeting because: the audio is usually worse quality; people are less expressive when staring at a monitor; and it is limiting having only a single monitor on which to display the possibly large number of video feeds from other sites together with any collaborative software in use. The key point to remember when using Access Grid from a workstation is the need to cancel echo. This can be done either by using a microphone headset, or by using an echo cancelling microphone.

At home: The current availability of high-speed broadband networks for domestic use means that it is now possible to take part in Access Grid meetings from home. To our knowledge, there are no commercial ISP's that offer multicast connectivity, so this is only possible using a bridge, such as those described here. In addition to this, Access Grid typically uses a lot of bandwidth (especially in large multi-site meetings) and therefore, even with a bridge, usage from home may not be straightforward. The version of IOCOM software known as IG2 incorporates low-bandwidth audio and video codecs and also allows the option to elect not to receive video streams. These features mean that IG2 can be used easily from home. Taking part in Access Grid sessions using the open source toolkit, however, is more complicated because RAT uses uncompressed audio by default, it is not possible to elect not to receive video streams, and the upload bandwidth may be a lot lower than for download, meaning that transmitting video may be impossible. Workarounds to these issues are: set RAT to use one of the audio codecs that uses compression; do not share video at all (i.e. turn VIC off)..

In an Office: Many of the features of Access Grid in larger nodes can be retained in an office at a reduced price and without the need for room modifications and yet still be suitable for use by 4-5 people with a far superior experience than from a workstation. Typically, an office Access Grid will comprise of a triple monitor display, PC, desktop echo cancelling microphones, and PC speakers. Prices for such systems vary depending on specifications and quantity of equipment.

In a Lecture Theatre: Most of the configuration issues relevant to installing Access Grid in meeting rooms are still pertinent when installing in lecture theatres. Particular issues to consider are camera placement, visible projector image, microphone placement and choice of microphone. Precise camera placement ensure good audience coverage as well as of those making presentations remembering that there may be more than one presenter at different locations. Ensuring that projector images can be seen even at the back of the theatre can be particularly challenging especially if there are multiple projectors. Proper microphone placement e.g. at a lectern for presenters and in the aisles for audience can make or break an AG session. Although it may be tempting to choose wireless microphones, these can require frequent battery replacement and can also be the cause of difficult-to-track-down echo when battery power is low so the microphone choices needs a good deal of consideration.

Q13: Where can I learn more about Multicast?

A: Here is a link to a guide produced for JANET available at http://www.ja.net/documents/publications/technical-guides/ipv4-multicast-web.pdf

Q14: How do I use shared/virtual whiteboards with the AG?

A: For information on how to use whiteboards with AG please talk to us.

Q15: Can Skype be installed on Access Grid nodes?

A: Skype can run on an Access Grid node but the services do not currently interoperate. In addition, if you install Skype on an Access Grid node rather than a desktop system, it may reset the Windows audio settings resulting in loss of outgoing audio from your node. To correct this re-set your Windows audio: set the record options to line-in rather than microphone. You may find this needs doing every time you log in, particularly if you have Skype auto-start enabled.

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