Netbooting without owning DHCP

I work for a college and manage a couple hundred computers including 50 iMacs. I want to use deploystudio to reimage my Macs. But being that my router switches aren't configured for hosting (i think this is the issue). I can't netboot, I can see my netboot option from the client computer, but it will not boot from the netboot set. Even when using a sudo bless command with the .nbi specified. Any Ideas? Please help. This is driving me up the wall. More Info: I do not control dhcp. I am on a large network controled by another department (computing services). Any better commands to issue using ard? Please and thank you. Forrest