mm06@bunny.UUCP (Michael Murphy) (07/06/88)
Well, are there? The IP-over-X.25 I mean is the one in
use by some csnet members ("x25net"). I am given to understand
that this is a different animal from DDN X.25. Csnet has an implementation
for Unibus and Q-bus vaxes using ACC cards, but we won't be able to
use this. There is a description of the protocol in a 1982 paper by
D. Comer and J. Korb "CSNET Protocol Software: The IP-To-X.25
Interface"; I do not know where this was published.
And now for the Obligatory Request: please mail directly
to me; I will post a summary of the replies.
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mike murphy mm06@gte.com {harvard,vaxine}!bunny!mm06philipp@LARRY.MCRCIM.MCGILL.EDU (Philip A. Prindeville) (07/08/88)
Yes, in a nutshell. The method for transmitting IP packets over X.25 requires: (a) the User Data field in the Call request contains 0xCC as the first octet and (b) the IP datagrams be sent over the VC aligned on packet boundaries, with packets greater than the maximum X.25 PDU being sent as complete-packet-sequences (ie. M bit on for all but the last packet of the seq). We use an ACC X.25 card to do this, and we speak to the original X25net hardware, which is an Interactive Systems (INcard). I have heard of people using the SUNlink X.25 S/W (in PDN, *not* DDN mode) with success. In fact, SUN has their own internal internet spanning North America and parts of Europe/Japan using IP over X.25. For more information, contact your SUN rep. As for the Comer/Korb paper, it was published by CSNet. It is available via anonymous FTP from sh.cs.net, as the file "dn5" (or something like that). I can mail it to you if you need it. Hope this helps, -Philip