Not sure how to explain this: I have twenty site that link back to my CO. We are installing an HVAC device at each site. Each HVAC controller sends a UDP broadcast to the other HVAC devices on network so that they see each other. I have a 3Com 5500 layer three switch at each site being used as the router with a 3Com 4500 switches as the core switch at each site. Some of the controllers are plugged directly into the 5500 and some are plugged into the 4500s. My question is, do I need to enable UDP broadcast on the routers and the switches for this to work properly or should it work regardless?