How does IBM Rational Performance Tester (RPT) assign IP addresses to each virtual users if "Enable IP aliases" is enabled in a location (agent computer)?
When IP aliases is enabled, it is expected that each virtual users have unique IP address available in order to emulate unique virtual users. However in some circumstances the number of IP address available may be less than the number of virtual users.
(For example; How RPT assigns IP addresses to 100 virtual users if only 50 IP addresses are available in a location).
When the location has IP aliasing enabled, RPT will ask the agent computer how many IP addresses it has available. It is up to you to have already configured the computer with these IP addresses. By default, RPT will use all IPv4 (but not IPv6) address available. You can also restrict the selection to IP addresses on particular interfaces.
If there are more virtual users on the location than there are IP addresses (which would normally be the case), RPT will distribute the virtual users evenly (more or less) across the available IP addresses. For example, if your location has IP addresses 192.22.22.02, 192.22.22.03, and 192.22.22.04 and you ran 10 users on the location, you would have a distribution similar to:
192.22.22.02: Users 1, 4, 7, 10
192.22.22.03: Users 2, 5, 8
192.22.22.04: Users 3, 6, 9
Note: On a Windows agent, you could use the ipconfig command to see how many IP addresses you have available.