Information Technology Reference
In-Depth Information
2.
The chapter outlines a computation indicating that 45 cables
would be needed to connect each of 10 computers to each
other using pointtopoint communications.
a.
Follow a similar approach to determine how many cables
would be needed for connecting 100 machines to each
other using pointtopoint communications.
b.
Use a similar approach to determine the number of cables
needed in general for connecting n computers following
pointtopoint communications.
3.
Another difficulty with multiple pointtopoint communica
tions for a single computer arises from the number and size of
the jacks needed for the task. A single RJ11 jack measures
about 3/8" by 5/16", and each jack must plug into an appro
priate socket. Although the socket must have some insulating
materials around its outside, let's ignore that for now to keep
computations simple.
a.
Focusing just on the size of the RJ11 jack, how much
space would be required for 100 jacks?
b.
The Internet contains millions of computers. Suppose these
were connected by pointtopoint communications, each
with its own jack. How much plugin space would 1 mil
lion jacks require?
c.
How does the space computed in part b compare with the
size of a typical modern laptop computer? (You will need
to measure a laptop—use your own machine, the laptop of
a friend, or a computer available in the school, an office, or
a store.)
4.
The discussion of star networks indicates that some central
machines form temporary connections from one computer to
another, so computers can send messages directly through an
established circuit. As an alternative, a central machine could
receive data from one computer, store that data temporarily,
and then forward the data onward to the intended recipient.
Consider each of these approaches for communications in the
context of bridges from one Ethernet segment to another.
a.
Could a bridge make a direct electrical connection from
one segment to another so that messages could go simulta
neously over both segments?
