Like the layering models, it's useful to picture communications net- work applications at the lower levels, and business or organizational functions at the higher levels. Each location where communications network facilities and services will be used will require physical layer network access and transport. Physical layer access may only appear in one single room in the establishment, but higher layer functions are likely to be spread around the entire building or campus with appearances in each office, cube, conference room, operations center, equipment room, or even outside in parking lots or production areas. Once an understanding of a business need is clear and mapped to equipment, facilities, and services, it's helpful and enlightening to analyze the traffic by breaking it out by type across organizational and/or operational function. Voice, data, and Internet access are likely to be at all workstations and many items of shared equipment; however, it's unlikely that anyone except key individuals in payroll, accounting, and human resources would have access to payroll infor- mation. Core content transport may be limited to certain operational functions and even compartmentalized to limit individual access in certain cases. It is also helpful to characterize each application with a priority. For example, all the traffic from all the users necessary to get a commercial on the air would logically take priority over download- ing a new commercial from an ad agency website. The selection and invoking of standards helps to define applications and facilitates acceptance. For example, once a supplier has been qualified, inspection and verification of compliance can be conducted on a periodic sample basis instead of dealing with each and every telephone instrument, network interface card, or other high quantity items. Circuit and facility acceptance test and verification can be reduced from 72 to 48 or 36 hours. Simply stating that compliance with a particular standard, engineering guideline, or recommended practice c