Our industry is very dynamic, with product schedules and delivery plans changing constantly. LoadSim is no exception. As many of you discovered, LoadSim 5.0 was not available on the Microsoft Web site. Instead, Microsoft decided to limit distribution of version 5.0 and widely distribute version 5.5. By the time you read this article, LoadSim 5.5 should be available from Microsoft's Web site. (You can download LoadSim at http://backoffice.microsoft.com/downtrial/default.asp?product=5).

If you are using one of the LoadSim 5.5 release candidates, no significant differences exist between RC1 (build 2108), RC2 (build 2172), and the final version. I recommend you start using the final version, but you won't have to throw away any data from the RC versions. If you have been using LoadSim 5.0, I recommend that you either continue to use that version until your tests are complete, or switch to 5.5 and rerun your tests. I do not recommend that you compare 5.0 results with 5.5 results; stick to the same revision of LoadSim for your entire test process.

As for protocol support, LoadSim 5.5 supports simulating only Messaging API (MAPI) clients, specifically the Exchange 5 client and Outlook 8.02. Note that the Outlook module that comes with 5.5 is a beta version. Microsoft has no plans to add Internet protocol support to future versions of LoadSim. For testing with Internet protocols, use InetMonitor 3.0 (formerly known as InetLoad) which ships with the BackOffice Resource Kit 3.0. InetMonitor has modules for Internet Message Access Protocol (IMAP), Post Office Protocol (POP) 3, Simple Mail Transfer Protocol (SMTP), Network News Transfer Protocol (NNTP), Lightweight Directory Access Protocol (LDAP), HTTP, and Internet Relay Chat (IRC).