An apparatus for transmitting a broadcast signal comprising a IP packet generator generating Internet Protocol (IP) packets including broadcast data for a broadcast service, a link layer packet generator generating packets including the IP packets, wherein the link layer generator comprises, an overhead reduction processor performing header compressions on IP headers of the IP packets, an encapsulator encapsulating the IP packets having the IP headers into the packets, and a link layer signaling encoder en coding link layer signaling data including header compression information specifying whether the header compressions are applied to the IP headers, and a broadcast signal generator mapping the packets and the link layer signaling data into data pipes is disclosed.