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

[Tony Mountifield]

In article <CAHZ_z=w5DMg93gShtC93kuC+fnmraPgV46BS956U5BQXVgyhxg at mail.gmail.com>,
Matt Fredrickson <creslin at digium.com> wrote:
> 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.

Hi Matt, thanks for the reply.

Both the 32-bit and 64-bit were fresh installs of the latest CentOS 6.9 from
online repositories using a kickstart build. I'm going to try installing the
64-bit version again tomorrow to see if the problem re-appears, just to be
certain it wasn't anything transient. I don't think there is anything unclean
about the spans, because they were running fine on CentOS 4 with the versions
I mentioned, and are now running well again with 32-bit CentOS 6.

Cheers
Tony
-- 
Tony Mountifield
Work: tony at softins.co.uk - http://www.softins.co.uk
Play: tony at mountifield.org - http://tony.mountifield.org