The state-funded network, called the Arizona Rural Telecommunications Network (ARTN), connects specialists at the University of Arizona's hospital and elsewhere with smaller hospitals, medical centers and, most recently, prisons across the state. ARTN is a private ATM network with IP-based store-and-forward applications, such as teleradiology, in which a CT scan is sent as part of a multimedia e-mail message. It also runs real-time ATM video clinical sessions between physicians and patients. Not surprisingly, ATM was the obvious choice back in 1996 when the network was built--VPNs (virtual private networks) had not yet taken off. "We run all this over our private network because we are concerned about security," says Kevin M. McNeill, associate director for network architecture with ARTN, based in Tucson at the University of Arizona.
With the IP-based teleradiology application, a local physician sends patient CT scans, X-rays, digital photographs and other information to a coordinator who refers the case to the appropriate specialist, typically at a big hospital such as the University of Arizona Health Sciences Center. "Some sites used to dial in before we had the high-speed connections and [information] took one to two hours to send," McNeill says.
ARTN uses LANE (LAN Emulation) to send these and other IP applications, including an upcoming distributed image archive for teleradiology, over the ATM WAN. LANE is infamous for its overhead and management issues, namely that it requires multiple "servers" to handle all the emulation. "I get beat up all the time for using LANE," McNeill says. "But we have found it to work just fine for us."
The good news with LANE is that you don't have to tweak your IP applications to work with ATM; the bad news is that since LANE lets these applications work transparently over an ATM network, you can't deploy ATM's QoS (Quality of Service) features for them.
Meanwhile, ARTN's emerging teleradiology archive not only would mean adding distributed storage technology, but also more bandwidth--at the least, among the three core switches--to run it.
Another bandwidth-heavy application about to hit ARTN is an anesthesia simulator, which will be used by medical students and residents. The application, which uses interactive video over ATM, can be programmed to simulate a patient's heartbeat and respiration while he or she is under anesthesia to train students at remote locations. "We will use videoconferencing, possibly in conjunction with data, which will impose additional bandwidth requirements for the network," McNeill says.
And change is afoot for the ARTN WAN transport. McNeill says his team is considering a microwave infrastructure in lieu of its DS-1-based ATM circuits, which cost about $350,000 per year. "We are concerned with failover and redundancy," he says, "so we may look at a combination of leased lines and microwave," or even an ATM service.
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