Internet Voice Distribution System (IVoDS)

Developed for Marshall Space Flight Center (MSFC) Flight Projects Directorate (FPD) to support International Space Station (ISS) communications, IVoDS allows Internet-based participants to talk/listen on one conference while listening to seven others. This multi-conferencing system links researchers, NASA Operations Personnel, and ISS crew together to support collaboration during Space Station experiment operations & planning.

The core component of IVoDS is the CUseeMe Conference Server. It establishes H.323 connections with the clients, mixes the audio from all talkers, and sends the audio out to all listeners. The gateway, developed by VoIP Group, converts audio between the telephony-based MSFC FPD Voice Switch and the H.323 IP-based conferencing system. AZ Technology developed the IVoDS-unique software to interface with and control the Conf. Servers, maintain the user database, authenticate users, and control talk authority on Air/Space-to-Ground conferences (PAYCOM). In addition, AZ Technology developed the IVoDS Client that provides the interface to the end-user. AZ Technology is the IVoDS prime contractor.

An IVoDS Administrator creates the conferences, adds/maintains user accounts, and monitors conference activity. The PAYCOM has the means to quickly disconnect a user from a restricted conference, if desired.

All Clients connect to the Conf. Server using the H.323 protocol for call signaling and media control. All audio packets are compressed using a G.723 codec (code/decode algorithm). All access between the IVoDS Client and the Admin/Conf. Servers takes place through a VPN (virtual private network). Each audio stream requires a bandwidth of 39Kbps (kilobits per sec).