Next: 3.3 User Interface Up: 3 Support Services Previous: 3.1.2 Backend Server Scalability
The issue of limited bandwidth concerns network applications which assume that the reliability and capacity of the underlying network is not sufficient. Thus, one goal is to keep the size of the transmitted data as small as possible by providing adequate data encoding schemes. When applying sophisticated data compression schemes, the availability of local resources for the encoding and decoding of the data has to be kept in mind. In general, since there is a tradeoff between managing bandwidth and the availability of local resources, a flexible strategy has to be provided which can be changed at run-time. For example, when the volume of the data is large and local decoding resources are available, apply adequate encoding mechanisms. Especially on the Web, the additional time for the decoding of the transmitted data has only little affect on the overall communication time. When the volume of the data is small, transmit the data without any additional encoding. This is also the default strategy.
Generally, scalability affects the limited bandwidth problem directly due to the increased volume of data, since an increasing number of clients demands an increasing throughput of method or object calls. The application middleware provides a solution to these problems by encapsulating the entire communication process and data transfer within the uniformly accessible message bus which offers a compressing, a secure and a default communication channel for transmitting messages. The strategy for choosing the appropriate communication channel is changeable at run-time.
Next: 3.3 User Interface Up: 3 Support Services Previous: 3.1.2 Backend Server Scalability Ralf-Dieter Schimkat
Thu Dec 9 14:08:00 GMT+1 1999