Hi Not sure I fully understand what you mean by broadcast port, but I'll give it a try:
the 8443 is for the ePO console only, port 80 is for agent to server communication (ASCI). You can see all the ports used if you click on configuration and then ports in the ePO console. It's the agents who initiate the update process. The server can only wake the agent up so the agents are forced to make a ASCI.