Errata exists for this version of the document.

This primitive data type is a UInt32 that represents the value of a counter. The initial value of a counter is specified by its use. Modulus arithmetic is used for all calculations, where the modulus is max value + 1. Therefore,

x + y = (x + y)mod(max value + 1)

For example:

max value + 1 = 0

max value + 2 = 1