Bandwidth is the amount of data transmitted or received per unit time, such as 100 Mbps. In a qualitative sense, the required bandwidth is proportional to the data’s complexity for a given level of system performance. For Table 4.1 illustrates the ranges of bandwidths commonly supported by the given technologies. Bandwidth is inexpensive in the LAN, where connectivity is typically limited only by hardware, implementation, and ongoing maintenance costs. In the WAN, bandwidth has typically been the overriding cost, and delay-sensitive traffic such as voice has remained separate from data. However, new applications and the economics of supporting them are forcing these conventions to change.