[asterisk-users] PRI Alarms, Comes Back, But Asterisk Won't Touch It!

[George Pajari]

Here is the scenario: Asterisk 1.14.13; zaptel 1.4.6; Digium TE120P 
(same problem with various previous versions; same problem with 
different TE120P cards).

The customer has a partial (10 B-Channel) PRI that when it is busy 
(eight or more B channels in use), tends to fail as shown below...

[Jan 26 23:00:31] ERROR[31893] chan_zap.c: Write to 28 failed: Unknown 
error 500
[Jan 26 23:00:31] ERROR[31893] chan_zap.c: Short write: 0/15 (Unknown 
error 500)
[Jan 26 23:00:31] WARNING[31893] chan_zap.c: Detected alarm on channel 
1: Red Alarm

we then see every channel fail with a write error followed by a Red 
Alarm. Then....

[Jan 26 23:00:34] VERBOSE[7646] logger.c:   == Primary D-Channel on span 
1 down
[Jan 26 23:00:34] WARNING[7646] chan_zap.c: No D-channels available!  
Using Primary channel 24 as D-channel anyway!
[Jan 26 23:00:36] NOTICE[7647] chan_zap.c: Alarm cleared on channel 1
(alarm cleared messages for all channels deleted)
[Jan 26 23:00:36] NOTICE[7646] chan_zap.c: PRI got event: No more alarm 
(5) on Primary D-channel of span 1

Yet even with all alarms cleared, a "pri show span 1" command shows 
"Status: Provisioned, Down, Active". It appears that Asterisk is not 
recovering from the errors.

Restarting Asterisk will not bring the PRI back up -- that requires the 
zaptel drivers to be unloaded and reloaded.

Why is this happening and what can be done about it?

-- 
George Pajari (dCAP), netVOICE communications 604 484 VOIP(8647) x102
   www.netvoice.ca  www.ip-centrex.ca  www.ip-pbx.ca  www.vpas.ca
     www.digium.ca www.grandstream.ca www.sipura.ca www.snom.ca
Open Source VoIP/Telephony Specialists  1 877 NET VOIP (638 8647 x102)