Much of the research literature available to the network designer may often appear impenetrable, since the language used to express ideas involves advanced mathematical notation. Although this book is not heavily numerical, it is assumed that the reader has a basic grasp of mathematics, as the use of mathematical conventions in some areas of network design is unavoidable. In this appendix we briefly review a selection of the more common techniques applicable to data communications design theory.

A.1 Operators

A.2 Numbers

Real numbers are numbers that can take a positive, negative, or zero value. For example:

• -400, -20, -11.75, -3, 0, +1, +3.76, +1000

Integers are whole numbers, positive or negative, that have no fractional parts. For example:

• -400, -20, -11, -3, 0, +1, +3, +1000

Rational numbers are fractional numbers and may be positive or negative. Rational numbers include fractions that are less than one, those that are greater than one (so-called improper fractions). Formally stated, rational numbers have the form a/b, where a and b are integers, b cannot be zero, and there are no common factors (i.e., 4/6 should be reduced to 2/3). Note that b can...