Network Bandwidth

The bandwidth requirements of ExtraView on a network are relatively modest. This is one of the advantages of ExtraView being a web-based application as opposed to being a client-server application.

The requirement, of course, is a function of how many people will simultaneously be accessing the ExtraView server, how much data they will transfer and the required response time.

The fastest response times to a user are required when inserting and updating issues and ExtraView is optimized to provide the best possible performance in these areas. Each time a record is inserted or updated, the data passed to the server is a function of the number of fields on the data entry form. The number of fields on the user’s screen largely influences this, especially if a significant number of UDF’s have been defined and are being used to pass significantly large amounts of data to the server. Of course, even the adding of a single large file attachment to an issue may require significant bandwidth. However, the very nature of ExtraView is that the most users typically use the software infrequently for a relatively short period of time each day. Statistics from multiple installations show that the average internal user makes between three and five updates per day. On average, each of these updates moves approximately 50 KB of data from the client computers to the server and the server sends approximately 10 KB of data to the client computer.

ExtraView optimizes the performance of the network and the application using many techniques. Of primary interest here is that wherever possible, a technology known as Ajax is used to eliminate screen refreshes which involve the creation of a new screen window. Only the data required to perform any purpose is moved between the server and the client browser. Secondly, wherever possible, ExtraView will compress the JavaScript that is sent to the user's browser. This is a trade off between reducing the amount of data transferred over the network, compared to the time to decompress the JavaScript within the client browser. Measurement shows this technique to be particularly valuable on low speed networks and networks with high latency. Note that the javascript/user_javascript/UserJavaScript.js file is not compressed as this would make custom development problematic.

Reports are highly variable in nature and, of course, it is typically a smaller number of users who will run large reports on a frequent basis. As a guide, an ExtraView Detailed Report that shows 100 issues will move about 200 KB of data from the server to the client.