A network adapter to support multicasting for EMCON restricted tactical subnetworks

It is assumed that within a tactical environment radio based broadcast communication is used to link subnetworks and/or hosts. It is a typical requirement for radio links within this environment to operate under EMCON (emission control) conditions. Hence these subnetworks or hosts, although being able to receive data, are not able to send any information back. Consequently, when being under EMCON restrictions, they cannot run any dialogue oriented protocol (e.g. application protocols like telnet, ftp, mail, etc. or routing protocols like DVMRP, PIM, etc.) to the outside world. However in a tactical environment it is highly desired that hosts being under EMCON restrictions continue in taking part in the information dissemination process for messages or files. This information distribution can be done very efficiently over radio based networks by using multicast addressing technology. As commercial routers normally do not support the military subnetwork types, it is necessary to develop special network adapters primarily offering an efficient access to the specific military network. This paper makes a proposal showing how the requirements of conventional unicast and multicast routing protocols can be fulfilled under EMCON restrictions to offer at least simplex connectionless traffic to the remote subnetworks or hosts.