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256 Chapter 10

What Then Can We Do?

Another topic that I addressed in the disaster recovery planning
book was to use what I termed “free space optics.” At the time, I out-
lined that in order to overcome the hesitation of installing fiber to
everyone’s door, the carriers may implement the speed and band-
width necessary over the airwaves. In the free space optics defini-
tion, I discussed that we could get hundreds of Mbps in the air to
manage our bandwidth needs. At the time, the choices were for RF
capability. The choices are outlined in Table 10-1.
Note that the speeds available were limited to 50 Mbps and less
for many of these choices. Some were also very slow compared to our
demands increasing exponentially. The motion for Local Multipoint
TEAMFLY
Distribution Services (LMDSs) and Multichannel Multipoint Distri-
bution Services (MMDSs) at the wireless local loop emerged as a pos-
sible substitute to a fiber or copper to the door. Unfortunately, the RF
choices available topped out at the 64-Mbps and below availability.
Moreover, the availability of the frequencies and the infrastructure
took too long to deploy for a customer to be satisfied. The ability to
dynamically add on capacity is not as easy as one would like. A rep-
resentation of the RF choice with LMDS and MMDS is shown in Fig-
ures 10-16 and 10-17 respectively.

Table 10-1
Technique Speed Distance Problem
Choices for Local
Access Microwave radio 8 T-1s is at 7-10 miles Licensing is
for local
dedicated to the
a problem
1544 Mbps
customer door T-3 at 44736 access
Mbps
Infrared light-based 6.312 Mbps Up to 1 1/2 mile Limited dis-
systems local access tance and
environmental
conditions
Cellular radio 64 Kbps up 3 to 5 miles Eavesdropping,
to 1.544 Mbps availability, and
cost
Fiber optics 622 Mbps 20 miles without Availability and
repeaters cost

Team-Fly
®