WDM: NA, part III
But the 1990s are different. Traffic is
increasingly dominated by data, not voice. Pacific
Bell has reported that its traffic became
predominantly data in 1995; all carriers report
growing amounts of data traffic. Goldman Sachs'
Mary Henry projects voice traffic continuing its
traditional lethargic growth pattern, while video and
data traffic continue an inexorable exponential
growth, reaching as much as 70 percent of traffic by
the year 2000. Specifically: voice traffic is estimated
to grow at 8 percent/ year, data traffic in total
(including modem dial-up access to the Internet and
corporate frame relay, among other things) is rising
at rates estimated at 35 percent/year. Internet traffic
within that continues its dizzying growth rates of
greater than 100 percent/year, creating the prospect
that overall traffic growth in North America might
actually accelerate further!
Most important, telecommunications markets
seem to have established a strong positive
elasticity; in engineering terms, they have found a
new positive feedback cycle. What this means is
that if the unit price of a telecommunications service
(e.g., 1 min of transmission at 1.5 Mb/s over 1000
km) declines by x percent, traffic will rise by (x + y)
percent, so revenues will rise by y percent. Thus, for
the foreseeable future, so long as unit prices for
telecommunications services can decline, traffic will
soar (and telecom revenues will rise). The realities
of the competitive market bear this theoretical
picture out: operators strive to capture enterprise
traffic from each other and from older forms (e.g.,
leased lines) by deploying new technologies that
lower the unit cost and price of their services. The
results, in general, are rapidly rising traffic and
higher network utilization.
As if this rising tide of traffic were not
enough, the major long distance carriers were in the
process of implementing SONET ring technologies.
SONET rings provide an important means to
eliminate the risk of network outages caused by
cable cuts. They use network systems that sense
the failure of a link, and then reroute the signals,
going in the opposite direction around the fiber ring.
These systems have a fast restoration mechanism
that is of great value in ensuring network reliability,
but do so by sacrificing fully 50 percent of the fiber
capacity! |
