[asterisk-users] Strange problem with PRI on 64-bit?

[Matt Fredrickson]

On Tue, Apr 3, 2018 at 5:44 AM, Tony Mountifield <tony at softins.co.uk> wrote:
> I have some more investigation to do on this, but I wanted to see if anyone
> here had any insight into the issue I've run into.
>
> The hardware is a HP DL360 G6 with a TE420 gen 5 4-port T1 PRI card. It is one
> of several systems that have been running without issue since 2010/2011. They
> have all been running CentOS 4 32-bit with Zaptel 1.4.12.1 (with patch for gen
> 5 card), libpri 1.2.8 and asterisk 1.2.32.
>
> Having taken this particular system out of production, I updated it to CentOS
> 6.9 32-bit, with DAHDI 2.11.1, LibPRI 1.6.0 and Asterisk 11.25.3 (this version
> of Asterisk is required at the moment due to custom modifications).
> This appears to work fine.
>
> In order to reduce the number of different versions we support, I reinstalled
> the OS using the 64-bit version of CentOS 6.9 instead, and rebuilt, using
> the same versions as above.
>
> However, for reasons I don't understand, the 64-bit version was logging
> frequent PRI errors every few minutes:
>
> [Apr  1 03:40:52] VERBOSE[8989] chan_dahdi.c: PRI Span: 2 TEI=0 MDL-ERROR (A): Got supervisory frame with F=1 in state 7(Multi-frame established)
> [Apr  1 03:40:58] VERBOSE[8988] chan_dahdi.c: PRI Span: 1 TEI=0 MDL-ERROR (A): Got supervisory frame with F=1 in state 7(Multi-frame established)
> [Apr  1 03:44:06] VERBOSE[8990] chan_dahdi.c: PRI Span: 3 TEI=0 MDL-ERROR (A): Got supervisory frame with F=1 in state 7(Multi-frame established)
> [Apr  1 03:46:38] VERBOSE[8990] chan_dahdi.c: PRI Span: 3 TEI=0 MDL-ERROR (A): Got supervisory frame with F=1 in state 7(Multi-frame established)
> [Apr  1 03:47:20] VERBOSE[8988] chan_dahdi.c: PRI Span: 1 TEI=0 MDL-ERROR (A): Got supervisory frame with F=1 in state 7(Multi-frame established)
> [Apr  1 03:47:24] VERBOSE[8989] chan_dahdi.c: PRI Span: 2 TEI=0 MDL-ERROR (A): Got supervisory frame with F=1 in state 7(Multi-frame established)
>
> This left the PRIs in strange states - trying to make a call failed with cause 101.
>
> So I re-installed the 32-bit OS again, and rebuilt, and the above MDL-ERRORs
> were no longer present, and the system operated normally again.
>
> So my question is: does anyone have any clues why there would be a difference
> in PRI behaviour between 32-bit and 64-bit builds? Has anyone else run into
> anything similar?


That does seem quite odd.  If I remember right, those messages would
come up if it looked like the other end hadn't received a message when
it thought it should have.  I can't think of anything that would
particularly impact 64 bit systems versus 32 bit systems in that
domain (ISDN real time message timing, etc).  Are you sure there's
nothing else different (kernel version or something else like that)?
Maybe also run a patlooptest on the spans in question to make sure
that they're running cleanly.

Matthew Fredrickson

>
> Cheers
> Tony
> --
> Tony Mountifield
> Work: tony at softins.co.uk - http://www.softins.co.uk
> Play: tony at mountifield.org - http://tony.mountifield.org
>
> --
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-- 
Matthew Fredrickson
Digium, Inc. | Engineering Manager
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA