The CPU footprint of Virtel is so small that it is unlikely to impact the MSU cap and therefore the cost of the mainframe system it runs on

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SysperTec benchmarked similar Virtel and TN3270 workloads on a z/OS system to compare the respective CPU footprints of both web access solutions. The following table provides estimates of Virtel overhead for small, medium, and large applications:

It doesn't make any difference in terms of CPU consumption whether Virtel is configured to:

• Replace 3270 emulation using the default presentation template for classic 3270 screen experience
• Create user-friendly web pages (GUIs) with JavaScript widgets (dropdown lists, graphical calendars, check boxes, etc) and new AJAX application features using custom-developed presentation templates

In both cases Virtel inserts the data sent by the 3270 application into an HTML/JavaScript template to create a web page file that it sends to the client browser for rendering. The GUI smarts coded in the template do not run on the host and do not consume host resources: they run on the client browser and consume client resources. With Virtel, a rich GUI doesn't cost more MSU than a web page emulating a 3270 screen.

Traffic volumes have been calculated conservatively so that most customers fall within or below our estimates.

It is unlikely that customers will ever experience an increase of their mainframe costs due to Virtel because:

• Most systems are "MSU-capped" so that they will not automatically resize into a higher MSU band in case of high CPU consumption to avoid unwillingly increasing the systems' costs
• Most systems are sized for average use at 60-70% of capacity: with overheads ranging between one and five 1000th of capacity, Virtel has very little impact on overall system use, and very little chance of impacting the MSU cap
• Virtel doesn't need to run in the CICS, IMS, or TSO partition it serves: if that partition is running close to capacity, Virtel can be configured to run in a partition with lower use (for example a batch partition) and to serve the CICS, IMS or TSO applications in cross-domain mode to avoid impacting the MSU cap
• The comparison above is based on a standard Virtel configuration where exchanges between Virtel and the application it serves are through VTAM... But Virtel can be configured to bypass VTAM and use cross-memory (EXCI) exchanges with the application it serves to further reduce the CPU footprint

To estimate for your own application the overhead of a Virtel-based screen-based web access or user-friendly GUI send us average and peak 3270 emulation traffic statistics (connection/transaction counts per period, bytes per transaction/connection, daily transaction count) and MSU base cost.

• Read about our product architecture
• Read abouttechnology differentiators
• Read about pure web VS TN3270
• Read about Virtel Web Access
• Read about Virtel Web Modernization