Raj,
You might check with iPlanet, either their website or somebody 'live', but I seem to remember being told to use 2-3 kjs PER CPU. So your test machine would need 4 at a minimum. I haven't had that kind of user load yet on our systems, so I don't have any experience with this.
That is interesting thought that the kxs is the one having the problem. Have you adjusted the min/max
thread count for it in the admin tool? I haven't messed with flow control or even know much about it, but that may be something you need to tune as well.
Are you using any kind of caching? Either at the server or the application level? If you can get the requests handled faster out of the kjs, maybe that would help.
Also, have you gone into 'Monitoring' in the admin tool and set up some stuff to monitor? It should be able to tell you something about what's going on. You might need to shorten the default time interval.
Good luck, and let us know how you end up getting it fixed, since we're all in the same boat with this software! If you end up dumping iPlanet, could you let us know the details on the decision?
Gerry