As part of the ACTS Tecodis project I participated in
a validation of Isabel over ISDN done during the fall 1997.
This resulted in a Technical report, TRITA-IT R 97:13, which I
was not part to (although I agreed with the conclusions).
Isabel was also used in the ACTS NICE project at
SICS.
I participated in the
Global360 demo 16/6 - 18/6 1997 in the SICS Grotto
and could conclude that Isabel hadn't improved since the evaluation.
ISABEL was a one year project devoted to put together two different ATM developments: RECIBA from Telefonica in Spain and RIA from Telecom Portugal. ISABEL is also the name of a cooperative work application developed on top of the ISABEL network infrastructure to demonstrate new usage of the emerging ATM technology [1]. It was also used in the RACE and ACTS summerschools 1993-1997. The ISABEL application runs on a Sun Workstation equipped with a Parallax Xvideo capture board generating MJPEG encoded video ranging from QSIF to 4SIF formats. Audio formats used are 8 - 16 bit PCM, the 8 bit format possibly compressed using GSM or G.721 codecs. It uses UDP/IP for transport. of voice and video and no loss recovery algorithms, so it needs a good quality link to work. A conference is initiated by a server to which additional clients may connect to participate in the conference. From the server, each client obtains the addresses of the other clients in the conference enabling them to set up and manage a mesh of point-to-point links. Thus ISABEL uses a mix of point-to-point mesh and reflector node technology to provide multipoint distribution. There is also a pure reflector-node-based version where each sender send to the server which in turn distributes the audio and video data using IP multicast [2]. Except from the audio and video it also incorporates a lot of X11-based shared collaboration tools.
Notes from Global360:
6Mbps ATM Unicast kontrollförbindelse 1 Mbps En central maskin styr övriga site:er via en kontrollpanel Handkonfigurerade route:ar till interaktiva site:er (IP to ATM) - slides över video (slöseri med bandbredd) - Talking head ibland - Använder inte inbyggd telepointer - Statisk mikrofon - Audio verkar ha lägre prioritet än video - Ej redundant audio kodning + Kan modifiera audio-uppspelningsbuffer - Blinkande videofönster vi restart - Icke robust - Default audiokodning: förlorade ATM-celler ger knäppningar och "rap"-effekter - Inte CBR video? - Silence detection som klipper för hårt (Bristfällig analog setup?) - Playback threshold i audiobuffern i kombination med hård silence detection gör att ljudet i slutet av en talspurt sparas till början av nästa talspurt. - Hårdvaru-reboot av centralmaskinen dödar lokal applikation 99% of the population of a normal european country are not aware of how technology work, and not even interested. Technology people are generally not aware of how people and society works. Technology and knowledge concentrated to the wealthy.
Maintained by Tobias Öbrink