In most cases, one SS will acquire the IP and/or MAC address of a peer either from the information derived from a TCP initiation from the other end, or through DNS in the case where it initiates. ARP usually does the L3-L2 address mapping where required. This behaviour is consistent with any other IP over 802 medium.

This memo defines an IPv4 option to provide a sender directed multi- destination delivery mechanism called Selective Directed Broadcast Mode (SDBM). The SDBM provides unreliable UDP delivery to a set of IP addresses included in the option field of an IPv4 datagram. Data reliability if required will be provided by the application layer. This approach was developed to support sender directed multi- destination delivery to sparsely populated groups with no additional control traffic. This approach will find application in the extremely bandwidth constrained tactical military environment, as well as in some commercial applications requiring sender control of data delivery.