[I asked this in alt...cisco, but there were no takers. Perhaps some of you Network+ folks have seen something on this] .... I've checked several sources, and I've seen the DoD/TCPIP model's Layer 3 equivalent written as "Internet" and "Internetwork." In the class lab book I've found it both ways. Which is it, or does it make any difference? While I'm on the subject, is it always safe to treat the "DoD Model" as synonymous with "TCP/IP." One other discrepancy, the Layer 4 equivalent is "Host to Host" apparently, but I have seen it listed in diagrams as "Transport" just like OSI's terminology. Thanks for your time.