[HECnet] Multinet protocol description

On May 8, 2013, at 5:14 PM, Dennis Boone wrote: Yes, I saw the DECnet/Linux code. It's rather puzzling because it seems to tie into a tun/tap device -- so it expects Ethernet behavior. But then it converts to short headers, which suggests point to point behavior. Which is it? The data headers are only a tiny part of the difference between the two datalink flavors... If I understood it correctly when I looked at it a while back, Multinet uses the DECNET point-to-point frame format in the UDP packets it exchanges with the remote. But Linux DECNET is unlikely to have any real hardware point-to-point links, and quite reasonably expects any frames from the local LAN (including those on e.g. a Linux virtual bridge from a simh instance running locally) to be in the broadcast format used by DECNET if its interface is an ethernet. Linux DECNET therefore converts between the two formats as necessary. Once I got past that, I was able to follow what was going on in packet captures based on how the Linux multinet program shuffled around array elements. Thanks everyone, I believe I got it now. paul