Organizations looking to invest millions of dollars in a new communications
network would be wise to develop a digital model of the system before
they commit to major hardware purchases. Although this advice seems
common sense, an expert said, it is surprising how many companies
and government agencies agree to buy new networks without really
knowing if they will work properly and meet their needs.
“When you are spending hundreds of millions of dollars on
a system, spending a small percentage on a simulation can help avoid
making a large mistake,” said Robert F. Brammer, chief technology
office at TASC, a division of Northrop Grumman Corp.
The company specializes in government and defense-related information
systems and analysis services. It has spent corporate research dollars
recently to come up with modeling technologies to simulate communications
networks and signals processing.
“There are several U.S. federal customers in sight”
for this technology, Brammer said in an interview. Projects currently
underway include communications network models for commercial satellite
firms, he said. The modeling covers the network’s basic physical
layer—predicting signal-to-noise ratios and achievable data
rates in various types of environments. The communications take
place via the Internet, by wireless terrestrial channels and by
space-to-ground channels.
“We worry about the fundamental physical communications channel
and network issues [such as] computer-to-computer protocols and
information security” that have to be included in the model,
said Brammer.
Models are done for different purposes, he explained. “In
some cases, you want to be able to predict the performance of a
communications system or network that a customer wants to build.”
In other instances, customers want to predict the network’s
performance in various environmental conditions.
“In other cases, they already have a network, so we build
a detailed model. In the event of an outage or emergency, we can
help with tactical planning of how to restore services,” Brammer
said. “There are number of reasons for the simulation models.”
High-fidelity models can predict failures, such as bottlenecks
in transmission, bandwidth availability and whether there is enough
computational power, he said. “They may be interested in trading
performance vs. security.” That means they must decide how
to transmit information at different levels of security through
a network. “You have to make sure that only the people who
are authorized to get the information can get it quickly and easily,”
said Brammer. “That is easy to say, but very difficult to
do in practice.”
Modeling of computer attacks is done frequently, he said. “Some
of these attacks have been well coordinated, involving thousands
of computers. So we have to be able to model what might happen and
what to do about it.”
The challenge for the industry, he said, is to “understand
how threats to the performance of communications systems are changing
as a result of rapid changes in computing and communications technology.”
At the same time, he added, “a lot of the technology is so
new and relatively immature, so there are security issues that you
have to be careful about.”
In information security, Brammer said, “we have a lot of
learning to do.”