multiple receivers of the same information. The physical aspect is one transmitter (albeit an expensive one) to many inexpensive receivers. If the satellite could radiate light waves instead of, or in addition to, radio waves, the consideration wouldn't change. What would change is the payload capacity for a given radiated source. It's well known that light waves are capable of carrying far more information than radio waves. The difference is primarily the fact that free space propagation or attenuation is dras- tically different than physical conductor propagation or attenuation. Network architecture is best described with a topology map or block diagram. Depending on the business requirements and nature of the traffic, the topology map and block diagram can be combined in a single figure and be used as a conceptual tool or have greater detail added and be used as a design detail document in test and acceptance work, network performance evaluation, or fault diagno- sis. The topology map or block diagram is used to capture and convey locations, number of sites, type of facilities, number and type of connections, service demarcation points, bandwidth, phone numbers, network domains, IP address, service provider boundaries and interface points, type and class of service, etc. Figure 5-2 is an example of a topology map or diagram that could be used to describe a network's topology and services required to support content trans- port, voice, data, and Internet traffic. This page intentionally left blank DEFINING NETWORK APPLICATIONS Application definition is perhaps one of the most critical work activ- ities or efforts in the practice of dealing with Internet and Telecom assets and resources. Define the application properly and it can significantly improve enterprise operations and profitability. Define it loosely, incompletely, or improperly and it could stifle growth, stop the business, or prevent a new venture from getting off the ground. Defining communications applications requires business and tech- nical knowl