Summary:ASTERISK-13239: Dahdi 2.1.0 causes HDLC Bad FCS (8) and Primary D-Channel on span 2 down
Reporter:Matt King, M.A. Oxon. (kebl0155)Labels:
Date Opened:2008-12-18 04:35:56.000-0600Date Closed:2011-06-07 14:03:11
Versions:Frequency of
Description:With one of our customers, with Dahdi 2.0.0, every day we see typically between 50 and 80 messages of the type:

chan_dahdi.c: PRI got event: HDLC Bad FCS (8) on Primary D-channel of span 2

These don't normally result in the span going down, so that's not so serious.

We tried upgrading them to Dahdi 2.1.0, and got *1400* of these messages over the course of the day.  The span went down 52 times over the course of that day.

I reverted them back to 2.0.0 and things seem back to normal.


I just thought you guys should know, in case this update causes problems for other users.  

We have a 2 span card, one span to the telco, the other span to their legacy PBX.  We always see these HDLC errors on the telco end, which is the timing source.

We're set to hardhdlc on the data channels for each E1 span.  Asterisk is run as a RT process, with a niceness of -20.

It would be great if we could find a way to get rid of these HDLC errors entirely...
Comments:By: Shaun Ruffell (sruffell) 2008-12-18 12:30:55.000-0600

kebl0155, could you contact Digium customer support about this.  They will be able to collect some information and triage your system in order to troubleshoot this.  That being said, I'm surprised by this report since there haven't been any changes to DAHDI between 2.0.0 and 2.1.0 in this area.  My best guess is that there is something that is just barely marginal in your original setup, so it would be worth working with them to troubleshoot the source of the errors on DAHDI 2.0.0.

By: Leif Madsen (lmadsen) 2009-01-20 14:18:30.000-0600

I'm going to close this issue as sruffell has directed the reporter to opening a case with Digium tech support for better triage of the issue. Thanks!