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

[Tony Mountifield]

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?

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