Data Communications Requirements of Distributed Database Systems - High-Performance Web Databases: Design, Development, and Deployment - page 469

Exhibit 31-1. Steps for determining database communications requirements.
the central site to maintain the integrity of the database. If updates are
made frequently, the network can become congested, further increasing
response time.
If a network does not have the capacity relative to the amount of data it
carries, the network will become congested, and response time will
increase. When evaluating network capacity, the number of current loca-
tions over which data will be distributed should be considered. In addition,
future locations should be accounted for as well as the number of users at
each location. Users should be classified as to the type of data they can
access. Those that have rights to update or query information at remote
nodes will have a direct impact on the amount of traffic generated on the
network. By identifying the type and frequency of remote queries made at
each node in the network, the total network capacity can be determined.
The media used to transfer data affects both capacity and performance.
A chart showing different media available for different network configura-
tions appears in Exhibit 2. The choices here include twisted-pair, coaxial
cable and fiber optics, as well as radiated signal from microwaves and
broadcast signals from satellites. For high-end performance, fiber optics