What are the networking requirements for AirPrint?

I'm trying to get AirPrint setup at work. I've used it at home with AirPrint Activator with no problems. But it doesn't seem to work on my work network. I suspect our network is too locked down to allow this. But I haven't been able to find any documentation that specifically outlines the requirements for AirPrint in terms of ports required, etc. I need to be able to give my network admin something concrete in terms of what he needs to do to open this up for me. Does such a document exist? Or can someone at least give me pointers on what needs to be opened up?