Strange AXIP / AX25 Frames

Strange AXIP / AX25 Frames

[Stewart Wilkinson]

Hi,

I have been looking into a problem on a remote (from me) Linux system
which is running a couple of AXIP links (configured as port '9'). 

The system is running Kernel 2.4.19 with libax25-0.0.10, ax25-apps-0.0.6,
and ax25-tools-0.0.8 .

'listen -ap 9' shows quite a number of corrupted frames, such as:

9: fm [invalid] to [invalid] via 90gGB7-2* M0GB7-3* [invalid] [invalid]* 
[invalid] gGB7BM 0GB7CR [invalid] ctl [invalid]0^ [DAMA]

which are repeated quite often.

as well as some like:

9: code 14 arg 132

Anyone got any idea what is going on here, or what might cause this ?

-- 
Stewart (G0LGS)
g0lgs@gb7lgs.co.uk

Re: Strange AXIP / AX25 Frames

[Wilbert Knol]

> 9: fm [invalid] to [invalid] via 90gGB7-2* M0GB7-3* [invalid] [invalid]* 
> [invalid] gGB7BM 0GB7CR [invalid] ctl [invalid]0^ [DAMA]

I had the same thing happen here, a couple of nights ago.
A re-boot fixed it.

Kernel 2.4.20 & latest AX25 apps, lib, tools. TNC-2 in KISS-mode.

Wilbert.

Re: Strange AXIP / AX25 Frames

[Robert Steinhäußer]

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Wilbert Knol wrote:
> > 9: fm [invalid] to [invalid] via 90gGB7-2* M0GB7-3* [invalid] [invalid]*
> > [invalid] gGB7BM 0GB7CR [invalid] ctl [invalid]0^ [DAMA]
>
> Kernel 2.4.20 & latest AX25 apps, lib, tools. TNC-2 in KISS-mode.

KISS mode normally has no checksumming, so any stray HF will mess up the data 
on your serial line between TNC and PC. Use shielded cabling and SMACK or 
RMNC-CRC-KISS or (even better for numerous reasons) 6PACK.

73, Robert DL1NC/N9KBK
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Re: Strange AXIP / AX25 Frames

[Thomas Osterried]

> > > 9: fm [invalid] to [invalid] via 90gGB7-2* M0GB7-3* [invalid] [invalid]*
> > > [invalid] gGB7BM 0GB7CR [invalid] ctl [invalid]0^ [DAMA]
> >
> > Kernel 2.4.20 & latest AX25 apps, lib, tools. TNC-2 in KISS-mode.
> 
> KISS mode normally has no checksumming, so any stray HF will mess up the data 
> on your serial line between TNC and PC. Use shielded cabling and SMACK or 
> RMNC-CRC-KISS or (even better for numerous reasons) 6PACK.

the initial question was for a problem with axip.
because axip frames have a checksum, these errors should not occur.


kiss: there are some checksum variants for kiss. one is crc-rmnc, the
other is smack. for crc-cmnc, there's no tnc software available. on the
other hand, smack is not implemented in the linux kernel kiss module.

considering this, 6pack is the better choice.


back to the problem. kernel 2.4.20 is quite new. it would be great if
you could test, if it is
  - a kernel problem
  - a problem with libax25 / ax25tools
  - listen does not exactly match with the libax25 library - a recompile
    may help

whil still running kernel-2.4.19, i could say nothing abt 2.4.20 issuses,
but if i remember correctly, there were only some scc driver fixes.


73,

	- thomas  dl9sau