Sonet links VA medical centers

Veterans Affairs Department hospitals and clinics in the Chicago area have brought up
the department’s first regional Synchronous Optical Network ring and a hybrid
copper-fiber WAN. It links eight medical centers and 28 outpatient clinics in five states.


The Veterans Information Systems Network (VISN) 12 began carrying data applications in
August. Video, including telemedicine applications, will be added later this year.


Craig Davis, the associate chief information officer, said moving video onto the
asynchronous transfer mode network from the public switched network will more than pay for
the move to the $80,000-per-month Sonet ring.


Moving intra-VISN 12 telephone service onto the network will increase the savings, he
said, and other commercial services that now cost $225,000 a month eventually could run
over the network at no additional cost.


The greatest benefits, however, will be better service to patients visiting remote
clinics, Davis said.


“We have some of the most advanced telemedicine applications in the country,”
he said.


The new network came about because VISN 12 services had been taxing the capacity of an
existing frame relay network supplied by Sprint Corp. In addition to providing video and
data communications for telemedicine, VISN 12 was one of the first networks in the country
to carry videoconferences.


“There has been a mass integration effort from a corporate standpoint,” Davis
said. “We needed an infrastructure to support it.”


VISN 12’s most remote medical center, in Iron Mountain, Mich., is almost totally
dependent on telemedicine. All diagnostic radiology takes place remotely at the Milwaukee
Medical Center 240 miles to the south. Pathology services rely on a remote-control
microscope developed at Iron Mountain. A technician mounts a slide, and a pathologist in
Milwaukee or the Hines Medical Center in Chicago controls the microscope.


A single telemedicine unit can demand as much as 800 Kbps of bandwidth.


“We’ve got a dozen of those units and 22 others that run at 384 Kbps,”
Davis said.


When as many as six telemedicine units are running at the same time for
videoconferences among eight centers, the network must carry about 10 Mbps of
time-dependent traffic in addition to routine administrative data traffic.


“The network was being horrendously stressed,” computer specialist Ken Vander
Waal said.


Transmission costs compounded the urgency because telemedicine and video calls over the
FTS 2000 network cost VA 24 cents a minute, or nearly $95,000 per month.


About two years ago, a VISN 12 team began laying plans for a Sonet ATM backbone that
could integrate voice, video and data, giving a good level of service for time-sensitive
applications. The team at first planned a single ring to connect all facilities.


“We had to modify the topology with a combination of Sonet and leased lines”
because some of the facilities were too remote, Davis said.


Ameritech Corp., the regional Bell operating company, supplies the Sonet ring that
links four Chicago-area facilities. Medical centers in Milwaukee, Madison and Tomah, Wis.,
as well as Iron Mountain, connect to it over T1 circuits.


Another 28 outpatient clinics stretching from Indiana to Iowa also connect by T1s.


The major medical centers have IGX 8410 ATM switches from Cisco Systems Inc. of San
Jose, Calif. IGX 3810 switches connect the outlying outpatient clinics. The Cisco units
were chosen because they could support the frame relay applications already used by VISN
12.


“We had an investment in our legacy technologies, and we wanted to maximize
that,” Vander Waal said.


Although the medical centers might migrate to pure ATM in the future, “we
haven’t pushed the presence of the network much past the front door,” said Troy
Tepp, one of VISN 12’s computer specialists.  

About the Author

William Jackson is a Maryland-based freelance writer.

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