2.7 Video over IP: The Adirondack Area Network
Several years ago, a project was initiated to link the local area networks of institutions in the northern part of New York State to provide the local communities in the rural Adirondack Mountains region with continuing medical education, distance learning, video conferencing, telemedicine, and remote legal advice.The teleconferencing solution needed to be inexpensive, yet provide all of the traditional line services and video conferencing capabilities.
The Adirondack Region posed a variety of challenges to those creating this network.Technology infrastructure and high bandwidth lines were lacking in many areas that would be required for the planned applications.Of these applications, one of the most desirable was telemedicine, as there was a limited number of health care facilities in the Adirondacks, and therefore limited access to medical specialists.Network applications in support of the medical field included high-resolution data transfers of diagnostic procedures, such as X-ray, magnetic resonance imaging (MRI), and other tests, facilitating access to medical specialists, and expedited patient diagnosis.When consultations were required, physicians at one hospital wanted to easily connect with their colleagues at other network-connected institutions in the area. Another networking challenge was financial, as the ultimate network design and its telecommunications services had to be delivered as cost-effectively as possible.
Today, that project, known as the Adirondack Area Network, or AANet (www.aanet.org), serves more than 150 institutions, including colleges, school districts, health care centers, legal organizations, hospitals, and the St. Regis Mohawk Tribe.In addition to connections averaging four per week within New York State, institutions from the neighboring states and the Canadian province of Quebec want to join the network.In fact, the Adirondack Area Network is confident that it will have 150 additional members on line by the year 2000.The network started as a collaborative effort among The Sage Colleges, Albany Medical Center, Franklin-Essex-Hamilton Board of Cooperative Educational Services in Malone, New York, Champlain Valley Educational Services in Plattsburgh, Bell Atlantic, RADVision Inc., Tandberg, Cisco Systems, the New York State Education and Research Network (NYSERNet), New York State, and other organizations.
During the design phase of the network, a number of infrastructure alternatives were considered. The LANs had various technologies, including FDDI, switched segments, and 10BASE-T, which also added to the design challenges. On the WAN side, ATM technology was available in the region but was eliminated because of cost. ISDN was considered, but its low bandwidth and lack of universal service in the region were concerns. Satellite up- and down-links were considered for distance leaming, but they were considered too expensive for two-way interactive video conferencing. Fractional Tl lines were also ruled out because of cost. As a result, frame relay was identified as the only economical, comprehensive WAN solution.
Thus, a hybrid cloud infrastructure, using frame relay and TCP/IP at the core and other technologies for access, offered an innovative solution to the region's networking needs. Some of these other technologies included Volp, ISDN, Ti, T3, ATM, plus the various LANs and end-user applications (Figure 2-7).
Member institutions access AAnet through a virtual connection (PVC) into the frame relay network. Frame relay is a flat rate service so there are no long distance charges within the cloud. Fractional bandwidths are possible and high bandwidth pipes, with transmission rates from 1.5 Mbps (Tl) to 45 Mbps (T3) are available. A frame relay network is a shared resource, and therefore the cost is substantially less than for traditional dedicated network models such as ISDN. By creating logical circuits in the frame relay cloud dedicated to video applications and other circuits dedicated to data, the AAnet guarantees the necessary bandwidth for high quality video. Instead of costly point-to-point connections, sites need only to connect to the nearest access point for the cloud. Sites receive Internet connectivity and high quality video connections for about the price of Internet connectivity by other means. The audio/video signal is of television/compact disc quality, even at 384 Kbps bandwidth. The video signals can adhere to a number of standards, including ITU-T H.323e, IP encapsulated H.320, or H.323. Multipoint video calls are also supported in this environment.
Much of the network infrastructure hardware was supplied by RADvision, Inc., of Mahwah, New Jersey. Two RADVision products were instrumental in the creation of this ground breaking video conferencing solution: ONLAN VIU-323 (Video Interface Unit) and ONLAN L2W-323 Gateway. By using the Video Interface Unit and connecting it to the room video conferencing hardware, developers found a way to enable the network to assess the video data as just another piece of information content that needed to be routed. The Video Interface Unit accomplishes this by taking the video data, a stream of data compliant with the Ff'U-T H.320 standard, and converting it into an IP-encapsulated H.323 stream or a pure H.323 stream.
The gateway functions as a video PBX that allows H.320 systems from the PSTN (ISDN) into the frame relay IP cloud. The Video Interface Unit (VIU) contacts the RADVision L2W Gateway, requesting the network address of the ISDN lines. Thus, the gateway enables the VIU to establish its network connection. In addition, the gateway, through its WAN ports, also enables video conferencing users to make multipoint calls. In other words, the gateway makes possible video conference calls that involve more than two participants through legacy multipoint control units (MCUs). The gateway also translates telephone numbers to IP addresses, in effect serving as a video conferencing PBX, with support for both Basic Rate Interface (BRI) and Primary Rate Interface (PRI) ISDN lines. As noted above, ISDN service is not available at all member locations; however, calls can still be made via the frame relay cloud through the gateways to the ISDN connection. Thus, institutions that are remote from ISDN services may still use full ISDN capabilities. In addition, the flexibility of being able to move video conferencing equipment from room to room without ever having to move lines is also provided.
Each institution on the Adirondack Area Network has its own programming and video conferencing-based content distribution as well. Producers have the option of posting their sessions to a public calendar with programs that are open to outside viewers. Those interested in a particular program ask for a port on the multipoint control unit (MCU) and can participate actively orjust watch a session.
One example of such programming is offered by the Albany Medical Center, Albany, New York. In January 1999, the hospitals connected to the AANet participated in the first live minimally invasive surgery, a technique that allows the surgeon to perform the operation from outside the patient's body. Scopes, lasers, and other surgical devices are placed through portholes within the patient's body. During the surgery, the surgeon's scopes and workspace video are encoded and digitally mixed in real time. The patient's surgery and the instruments are visible in a split screen, while the surgeon is viewed in the other portion of the screen. To make this procedure visible to all call participants, the operation was broadcast to two rooms on the host campus, plus five other sites that joined via the frame relay network. The multipoint call is completely interactive; the surgeon can be seen and heard by participants, and those participants may pose questions to the operating room during the procedure.
A second example of the network's utility is in its support of natural disaster recovery efforts. When a savage ice storm ravaged this North County region during January 1998, New York State's Department of State deployed the Adirondack Area Network to assist and speed up disaster recovery. By using the AAnet, the Department of State was able to maintain direct voice and video contact with its lead people who were working around the clock to rebuild the shattered electric power and telephone systems in the stricken region. The network, which doesn't rely on standard telephone lines, was especially useful in areas that were without regular phone service for several weeks. Shortly after this devastating ice storm, floods hit many of the same areas. Again the design held up as a valid disaster recovery plan. Since that period many AAN institutions have implemented these processes into their individual disaster recovery plans.
By using frame relay and this network model, the average connection costs less than $1,000.00 per month. Other teleconference systems might cost as much as $100.00 per hour for video conferencing alone. A school or health care organization could purchase everything necessary for joining the network for about $70,000.00. Development of the network was supported in part by a $1.4 million grant from the Bell Atlantic Foundation, which thus reduced total project costs.