I admit PhD students together with the other Professors in the Networked Systems Lab. If you're interested in working with me/us please apply to USC and list us as the faculty you'd like to work with. This will ensure we see your application.
For tips on how the process works and how to maximize your chances I recommend this slide deck from Matt Welsh. I endorse most of what is in there, but, in contrast, I think the research statement matters a lot.
In your research statement I recommend you tell us about past research you've done and proposed research you want to do. For past research tell us why the problem is interesting and important, and what your specific (very specific!) contributions were. For proposed research tell us why the problem is interesting and important, and how you think you could tackle it.
USC MS students interested in working with me should take my class and be one of the top students. If you're interested in working with me, you should indicate that in your application to the class (and explain why!).