This International Standardized Profile is applicable to interworking units concerned with operating in the Open Systems Interconnection (OSI) environment. It specifies a combination of OSI Base standards that collectively provide a Network Relay function for the connectionless-mode Network Service. This part of ISO/IEC ISP 10613 specifies the RA51.54 profile, which is applicable to interworking units operating between CSMA/CD LAN subnetworks and FDDI LAN subnetworks.