[nos-bbs] Remote AX25 Attach with JNOS

Barry Siegfried k2mf at nnj.k2mf.ampr.org
Wed Apr 6 16:32:26 EDT 2005

[maiko at pcs.mb.ca wrote]:

> > axip has the advantage that it has all the tcpip transport functions so
> > you can be sure that everything that is send will get there in the end
> Sorry but that is not correct. See the following :
>   http://www.iana.org/assignments/protocol-numbers

Whew!  I'm glad Maiko cleared up that one!

> AXIP is an IP protocol, at the same level as the other IP protocols,
> like UDP, TCP, ICMP, EGP, and the list goes on.
> AXIP is simply AX25 frames in IP.  There are no transport functions,
> it's more or less raw IP.  There is no guarantee that the frames will
> get to the other end.

Correct, BUT if you are encapsulating AX.25 VC frames, then the AX.25
level 2 time out will see to it that any lost frames are resent.

> There has been talk in past times about having a AXTCP (which would see
> AX25 Frames transported over TCPIP).  But I don't see the point of that.

*Particularly* since hams invented a level 2 "timeout" using VC mode
it is not even necessary.  What about for UI frames you say?  Ah well,
nothing is perfect.

> > where axudp has no garantees
> AXUDP is AX25 frames in UDP.  More or less the same functionaly as AXIP,
> but with the extra size of the UDP header.  Functionally the same thing.
> > axudp is easier to route over firewalls and routers.
> Yes.  AXIP is not easy or just impossible to route through alot of
> the cheap home units.
> > so if you can get it to work axip is better
> I would say for most DSL and Cable users, that AXUDP is a better choice,
> since UDP is passed by most home and consumer routers, where anything
> other than UDP, TCP, or ICMP (ie AXIP) likely will not make it.

If you need to use 44-net IP addresses for the end links of your
AX.25 link and you have a cheap home cable router that won't pass
anything other than ICMP, TCP and UDP, then you could use IPUDP
(like IPIP only with the extra size of the UDP header) and then
use your 44-net IP address to encapsulate an AXIP link to the
other end.

73, de Barry, K2MF >>
          <|>      Barry Siegfried
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