I was reading DHCP ( RFC 2131 ), I have basic knowledge about Relay Agent and Broadcasting. But for Understanding DHCP in depth, I felt like I have to know Broadcasting and Relay Agent ( RFC 1542 ) in details. But could not find any RFC (RFC919,922 not much helpful) for broadcasting in details.

1. How broadcast packet routes ? Because if the packet is intended for a different network than source, obviously the router will drop the packet. Is there any protocols for this ? Does router prevents all broadcasting or only the Limited/Local broadcast ?

2. Can we send a packet with destination as a direct/limited broadcast IP without a broadcast MAC address ? If Yes, I think because of a perticular MAC address the packet will forward to a single Host, So the question, in which case this would be helpful.

3. Consider a router is enabled by relay agent. When a DHCPDiscover ( which is a broadcast packet ) comes to that router, How does it proceed ? Because first thing its a broad cast IP also the network "0" is there, Does always relay-agent first checks the packet if the Packet is of DHCP ? 

My questions are not from a perticular subject (DHCP ond Broadcasting ), so you might be angry, But Please do help me. Thank You