The packet receive interface between the IP layer and the link layer MUST include a flag to indicate whether the incoming packet was addressed to a link-layer broadcast address.
Although the IP layer does not generally know link layer addresses (since every different network medium typically has a different address format), the broadcast address on a broadcast-capable medium is an important special case. See Section 3.2.2, especially the DISCUSSION concerning broadcast storms.
The packet send interface between the IP and link layers MUST include the 5-bit TOS field (see Section 3.2.1.6).
The link layer MUST NOT report a Destination Unreachable error to IP solely because there is no ARP cache entry for a destination.