Boolean logic is based on digital circuitry that accepts one or two incoming voltages. Based on the input voltages, output voltage is generated. For the purpose of computers the voltage difference is associated as two states, on or off. These two states are in turn associated as a 1 or a 0, which are the two digits in the binary numbering system.

Boolean logic is a binary logic that allows two numbers to be compared and a choice generated based on the two numbers. These choices are the logical AND, OR and NOT. With the exception of the NOT, Boolean operations have the same function. They accept two numbers, which are 1 or 0, and generate a result based on the logic rule.

The NOT operation takes whatever value is presented, 0 or 1, and inverts it. A one becomes a zero and a zero becomes a one. Remember that the logic gates are electronic devices built specifically for this purpose. The logic rule that they follow is whatever the input is, the output is the opposite.

The AND operation takes two input values. If both are 1, the logic gate generates a 1 output. Otherwise it outputs a 0. There are four combinations of input values. Three of these combinations generate a 0, and one combination generates a 1.

The OR operation also takes two input values. If at least one of the input values is 1, the output value is 1. Again there are four combinations of input values. This time three combinations generate a 1 output and the fourth generates a 0 output.

The two networking operations that use Boolean logic are subnetwork and wildcard masking. The masking operations provide a way of filtering addresses. The addresses identify the devices on the network and allows the addresses to be grouped together or controlled by other network operations. These functions will be explained in depth later in the curriculum.

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