Hello, On Mon, Feb 7, 2011 at 12:21 AM, Guy Harris <[email protected]> wrote: > > On Feb 4, 2011, at 12:25 AM, M.Baris Demiray wrote: > >> In fact this is not what STANAG 5066 Annex H "Implementation Guide and >> Notes" section suggests. According to this section and the tests held >> by DRA (Defence Research Agency), >> >> 1) The throughput is not strongly sensitive to frame size >> 2) 200 bytes is a good 'compromise' selection for frame size >> >> Besides, STANAG 5066 has the ability of doing DRC (Data Rate Change) >> in accordance with SNR values so what is suggested by that white >> paper, I think, is not applicable. > > That's somewhat of an implementation detail that shouldn't affect code that > tries to dissect those packets.
While I was writing this I was aware that I was diverging from the topic a little yet I wanted to add that since now I use DLT_USER0 and there are header and payload size fields at the Wireshark interface where I associate DLT_USER0 and s5066mac dissector. So I thought it may be helpful to provide that information. Sorry if I bothered with implementation details. >> Precisely. Yet may be a little clarification is needed. You might have >> noticed that in my first e-mail I mentioned about DTS (Data Transfer >> Sublayer) and that one of our dissector methods has the name >> dissect_s5066dts() but now we are talking about MAC layer and all this >> may look like a confusion but it is not. As explained in Isode white >> paper there are three versions of STANAG 5066. MAC (Medium Access >> Control) layer was introduced in Edition 2 (which was later renamed as >> Edition 3) and designated to manage HF modem interface that DTS was >> designated to do the same before. > > So is there a publicly-available specification that documents what the > packets using this link-layer type look like?- Unfortunately no, there is not. As in SIS Layer dissector this is also a part of a standard which is available only to NATO member states and that therefore we access through an account. However there is a version called 1.0.2 on the Internet and there you may find the section C.3 Structure of sublayer protocol data units (D_PDUs) in order to observe what a DPDU header looks like. This is a really old version and I think that's why it's unclassified. Here is the link, http://www.armymars.net/ArmyMARS/HF-Email/resources/stanag5066.pdf Besides this I will check if I can provide any recent versions of DPDU headers. Thanks, > This is the tcpdump-workers list. > Visit https://cod.sandelman.ca/ to unsubscribe. -- M. Baris Demiray - This is the tcpdump-workers list. Visit https://cod.sandelman.ca/ to unsubscribe.
