A petabit is one quadrillion (1015) binary digits and is used in discussing possible volumes of data traffic per second in a large telecommunications network. A petabit is one thousand terabits. Petabits per second can be shortened to Pbps.
Although the bit is a unit of the binary number system, bits in data communications have historically been counted using the decimal number system. For example, 28.8 kilobits per second (Kbps) is 28,800 bits per second. Because of computer architecture and memory address boundaries, bytes are always some multiple or exponent of two. See kilobyte, etc.