Ethernet has evolved from using coaxial cable to a star topology using hubs and switches connected by UTP cable or fiber optics. FDDI was the first standard developed for high-speed local area networks using fiber optics in a dual counter-rotating ring topology. IBM's ESCON network connected mainframe peripherals in a switched star architecture using fiber optics, starting at 4.5 MB/sec and increasing to 10 MB/sec. Today most large networks use fiber optics in the backbone and UTP cabling at the desktop, allowing speeds up to 100 Mbps to individual devices. Fiber optics is also used in cellular networks, wireless LANs, utility grids, security systems, building management, industrial process control,

1. FIBER OPTIC BASICS
Part 6 - Evolution of Ethernet

2. Evolution of Ethernet
Ethernet began as
a coax network
using physical taps
onto the cable. It
has evolved into a
star architecture
using hubs and
switches. Devices
are connected to
the hub or switch
using UTP cable or
fiber optics.

3. FDDI-The First All-Fiber Network
Fiber Distributed Data
Interface (FDDI) is a high
speed local area network
standard that was
developed specifically to
use the advantages of fiber
optics by the ANSI X3T9.5
committee. Careful
development means that
interoperable products were
readily available.

4. FDDI-The First All-Fiber Network
FDDI has a dual counter-
rotating ring topology with
dual attach stations on the
backbone that are attached
to both rings and single
attached stations that are
attached to only one of the
rings, through a
concentrator. This dual-
attach structure allows for
one primary ring and a
backup ring.

5. FDDI-The First All-Fiber Network
Failure of either a node or a cable link is bypassed by
fiber optic switches in the node or looping back along
the two rings. It has a token passing media access
protocol and a 100-Mbit/s data rate.

6. IBM ESCON Mainframe Network
ESCON is a IBM-developed
network that connects
peripherals to the
mainframe, replacing "bus
and tag" systems. ESCON
stands for Enterprise
System Connection
Architecture. The network
is a switched star
architecture, using ESCON
directors to switch various
equipment to the mainframe
computers.

7. IBM ESCON Mainframe Network
Data transfer rate started at 4.5
megabytes/second but is now 10
Mbytes/second. With a 8B/10B
conduiting scheme, ESCON runs
at about 200 Mbits/sec. ESCON
was the key to interfacing main-
frames to the new PC LANs as
they developed. IBM offered
ESCON gateways that connected
to Ethernet, Token Ring, and
various telecom networks to
allow communications between a
mainframe and just about any
other device.

8. Fiber Optic LANs
• Every LAN offers a fiber option or can be
converted with “media converters”
– (Ethernet, Token Ring, Arcnet, etc.)
• FDDI was first LAN designed for fiber
• ESCON the first mainframe back-end network
in fiber
• LAN Backbones today are predominately
fiber
• Fiber to the desk has not been popular due to
cost of electronics

9. Fiber Optic LANs
Today most large LANs use fiber optics in the backbone and
UTP cabling to the desktop. The backbone is running at
100 Megabit/s or 1 Gigabit/s while 100 Mb/s is the max to
the desktop. Backbone distances and speeds, along with a
interest in going to even higher speeds (10 Gb/s) makes
fiber easy to justify in the backbone. In fact most backbone
cables have both SM and MM fiber for future upgrades.
But Category-rated UTP has been able to handle the desktop
connection speeds so far and the traditional architecture
standardized in TIA/EIA 568 favors the UTP solution.
Some users have analyzed using fiber to the desk without a
telecom closet (or telecom room as it is preferentially called
today) and found it cheaper than a backbone fiber/desktop
UTP connection, when one downsizes the telecom closet or
doesn’t use it all, due to fiber’s architecture not needing the
space, power, ground or AC.

10. Other Applications of Fiber Optics
Communications
– Cellular/Wireless/PCS
antennas
– Wireless LAN antennas
– Utility network management
Security
– Closed-circuit TV
– Intrusion Sensors
– Surveillance proofing
Fiber has found many
other uses.
Cellular systems are
not wireless - most
antennas are
connected via buried
fiber optic cables.
Likewise, wireless
LANs require cabling
and fiber provides
greater distances from
hubs and switches and
immunity to noise.

11. Other Applications of Fiber Optics
Communications
– Cellular/Wireless/PCS
antennas
– Wireless LAN antennas
– Utility network management
Security
– Closed-circuit TV
– Intrusion Sensors
– Surveillance proofing
Utilities have used fiber
for managing their
grids and
communications
throughout their
networks for many
years. Recent problems
have had many
upgrading their
systems.
Security systems use
lots of fiber.

12. Other Applications of Fiber Optics
CCTV cameras use fiber to extend their reach, for
example in large airport terminals, outdoors in power
plants or inside and outside big office buildings.
Fibers can also be used as sensors, for example
sensing intruders on fences or walking across buried
fiber sensors.
And, of course, fiber is very difficult to “tap,” making it
popular for secure military and government networks.

13. Other Applications of Fiber Optics
Building Management:
Process Control
Sensors
High voltage/current
Chemicals
Hazardous
environments
Building management systems can
use fiber in place of copper cable for
longer distances and greater
security.
Industrial networks favor fiber for
process control applications due to
its distance capability and immunity
to electrical noise.
Fiber optic sensors are available for
a number of applications, including
measuring high voltages and
currents as in power grids,
dangerous chemicals and can
operate in hazardous environments
since they are intrinsically safe.