User's computer crashes when accessing Web site: Configuration problems with client machine, modem, or connectivity devices (e.g. cables)
User cannot connect to network devices: Router or other network hardware not connected correctly
Web pages download slowly: Client machine has too little memory, modem is too slow for anticipated downloads, server is overworked
User receives an error message when accessing a site: Web server is offline, site has moved to another URL, network at server end is down, firewall is improperly configured.
Only part of a file arrives: Bad router or network connection between client and server, cabling problem, bridge or router configuration problem.
Video reception is slow or uneven: Modem connection is too slow, Web server is very busy, IS
Even the best programmers occasionally write programs with errors. Errors can also be caused by
incorrect user inputs,
hardware failures, and
network failures.
A good programmer anticipates such problems and writes programs that respond gracefully when they occur. ASP.NET provides programmers with a number of powerful tools for debugging and error handling. ASP.NETs Try-Catch blocks allow programmers to write custom error-handling routines for problematic code, such as database accesses. When errors occur Try-Catch automatically redirects program execution to specific error-handling code blocks. The feature can be
used to provide a graceful response to the user and to report the problem to the system administrator. ASP.NET's trace object provides developers with a useful tool for debugging and fine-tuning code during development.
The trace object provides detailed analysis of code execution, including order of execution, CPU time, and memory usage
The application service provider is the entity that offers the outsourced application to the customer over the network.
However, the ASP must neither own the software, which it may license from an independent software vendor, nor must it own or operate the hardware, which it may lease from a server farm provider. In a further breakdown,
an ASP aggregator bundles several ASPs together and offers the user one unique interface.
This may be as simple as offering an ASP directory, a common log-in, and authentication, or more complex in that data can be seamlessly exchanged between the different ASPs.
ASP aggregators strongly depend on open standards for accessing disparate ASPs through software integration. The emerging Web Services standards may constitute a viable solution.
The overall architecture of a model ASP is depicted in Figure 5-6, which shows the interaction of the different elements of the ASP value chain.