OM1/2 OM3 OM3/4 × n
Cat 5e Cat 6 Cat 6A
1995 2005 >2015
Physical layer architectures
for enterprise networks
Networks incorporate more applications than ever before,
and for many, new architectures best serve user needs.
BY PATRICK MCLAUGHLIN
When the concept of a structured cabling system emerged and took hold
in corporate environment, user needs
in enterprise networks were fairly
straightforward. A wired voice line and
wired data line to each desk connected
each worker to the outside world as
well as to internal network devices and
applications such as email, intranets,
and printers. To be prepared for future
needs, some organizations specified
one or two spare connections to each
desk. Typically, most workers resided
in open-office (cubicle) workspaces.
Some resided in hard-walled offices, so
the cabling-system design had to accommodate for these different physical workspaces.
Wireless networks theoretically operated in the range of double-digit
Megabits/sec. But that’s shared
throughput, so the handful of workers
in an enterprise who had mobile work
devices (e.g. laptop computers) shared
that data rate when they gathered in
a conference room that contained an
Now that we have taken a trip down
decades-old memory lane, we can com-
pare and contrast characteristics of
worker needs then with worker needs
now. In many cases, the buildings and
campuses have not changed much—drop
ceilings, cubicles (albeit with different
wall heights perhaps), conference rooms,
walled offices for executives—but user re-
quirements have changed significantly.
On one hand, speeds have increased.
The scenario described earlier likely
had 10-Mbit/sec data connections to
the desktop initially, with 100-Mbit/sec
network backbone speeds. When 100
Mbits/sec to the desk became practi-
cal and common, backbones had to ac-
commodate by increasing to 1 Gbit/sec.
For many organizations, the advent of
the 1-Gbit/sec backbone also meant de-
ploying fiber-optic cabling to support
it. Today, some of those organizations
have increased tenfold again, with
1-Gbit/sec connections to the desk and
10-Gbit/sec backbones. Wireless LANs
have experienced multiple generations
of advancement, to the point at which
the (theoretical, shared) throughput ca-
pability today is multi-gigabits.
Taken from the CommScope white paper “Fiber backbone cabling in buildings,”
this illustration shows the evolution in speed of backbones and horizontal links.
Note the current scenario depicted on the right shows various end devices
connected to the network.