[asterisk-biz] PRI dropped calls, D channel traces, and more

Thu Apr 2 00:07:05 CDT 2009

Hi Mitul,

Mitul Limbani wrote:
> Hi harry,
>
> Over the past 1+ year I have encountered similar issue as u saying,  
> bad HDLC and the line resets dropping all the calls on the line.
>
> After diagnosis of each different case I got the following reasons:
>
> 1) the card is conflicting with some other resource on the pc, 90%  
> time it conflicts with either the USB controller or Ethernet  
> controller, try disabling these hardware or try different PCI slots or  
> in some cases I have tried entirely different PC and the line drop  
> issue disappeared.
>
> Cat /proc/interupts
>   

Well, unless I am reading this wrong, we don't have any IRQ sharing:

hmcgregor at rppbx:~$ cat /proc/interrupts
           CPU0       CPU1      
  0:         34          1   IO-APIC-edge      timer
  1:        294       2955   IO-APIC-edge      i8042
  6:          0          3   IO-APIC-edge      floppy
  7:          1          0   IO-APIC-edge      parport0
  8:          0          1   IO-APIC-edge      rtc0
  9:          0          0   IO-APIC-fasteoi   acpi
 12:         19        318   IO-APIC-edge      i8042
 14:          1         87   IO-APIC-edge      ide0
 18:  194114861  481832830   IO-APIC-fasteoi   wanpipe1
 19:   86761424  251172881   IO-APIC-fasteoi   wanpipe2
 20:     841032    9434148   IO-APIC-fasteoi   sata_nv
 22:          1        117   IO-APIC-fasteoi   ehci_hcd:usb2, HDA Intel
 23:     408202    4839750   IO-APIC-fasteoi   ohci_hcd:usb1, sata_nv
1276:    3077018   47863500   PCI-MSI-edge      eth0
NMI:          0          0   Non-maskable interrupts
LOC:   13557666   16509579   Local timer interrupts
RES:   20741331    8566946   Rescheduling interrupts
CAL:       1755        297   function call interrupts
TLB:     210532     232038   TLB shootdowns
TRM:          0          0   Thermal event interrupts
THR:          0          0   Threshold APIC interrupts
SPU:          0          0   Spurious interrupts
ERR:          1

> 2) Use Xorcom's AstriBank although it is bit exp and doesnt have  
> onboard echo cancellation v/s PCI cards but you dont have worry about  
> PCI slots n stuff anymore, no line drop due to HDLC has been reported  
> by any of my customers using the Xorcom hardware.
>   

That may be an option....
> 3) If you did 1 and still facing issue raise a support ticket with  
> Sangoma they would definitely fix or provide cure
>   

Ok
> 4) based on 1 and 3 you can go back to telco and get them to layout  
> the Fibre once again from their junction box, coz then your line is  
> failing due to physical disturbance in line, and this is something  
> which the tester unit is capable to withstand, but not asterisk. So  
> although they show you line perfectly ok on their tester units it  
> would fail after unpredictable time delay on asterisk.(make sure you  
> fix 1 and 3 before doing this or else you loose reputation in front of  
> customer and telco both)
>
>   
The telco has not even been running a T-Bird, just a loop test on the
smart jack and their CPE equipment.

Since it's an integral access type setup, there is the incoming telco T1
into the Telco's CPE equipment, which then hands over ethernet for
internet access, pots for our fax lines, and fractinal PRI for our
digital voice trunks.

It's quite possible that most, but not all of our issues are on that
fractional PRI, and not the incoming T1.

                         Harry
> Let me know,
>
> Regards,
> Mitul Limbani,
> Founder & CEO,
> Enterux Solutions Pvt Ltd,
> The Enterprise Linux Company(r),
> http://www.enterux.com/
>
>
> On 02-Apr-09, at 7:21, Harry McGregor <hmcgregor at biggeeks.org> wrote:
>
>   
>> Hi,
>>
>> We are having some issues with dropped calls on our combined voice/ 
>> data
>> T1 (ISDN PRI hand over of the voice channels).
>>
>> Our users are reporting frequent (3-10/day for an 8 person office)
>> dropped calls, including calls with the other party being on a land  
>> line.
>>
>> The telco keeps coming back that the line is clean.
>>
>> Anyone here have solid experience in reading through D-Channel  
>> traces to
>> figure out what is going on exactly, enough that we can either fix our
>> Asterisk issue or push the telco for a fix.
>>
>> Most of the issues started when we switched from doing our own analog
>> split out for fax (Sangoma T1 card, Sangoma Analog), to having our  
>> telco
>> split out the fax lines.
>>
>> We had issues with fax reliability on the sangoma pair (even though it
>> had worked well for us in the past with other installs), and  
>> switched to
>> telco analog hand over for fax (which permitted the Windows SBS fax
>> server to work, though we are getting a lot of cut off faxes).
>>
>> Environment is Asterisk 1.4.21 on Debian Lenny Kernel 2.6.26
>>
>> 01:06.0 Network controller: Sangoma Technologies Corp. A101 single- 
>> port
>> T1/E1 (rev 01)
>> 01:07.0 Network controller: Sangoma Technologies Corp. A200/Remora
>> FXO/FXS Analog AFT card
>>
>> -----
>>
>> We really need to get to the bottom of this fax issue.  We can provide
>> logs, and we can provide supervised (screen),bastion host based SSH
>> access to the asterisk system.
>>
>> I would like to keep the cost down of course, but can offer between  
>> $150
>> (looking at the logs, giving suggestions), up to $500 (if you can  
>> truly
>> solve the issue, and our users are happy).
>>
>>
>>                                        Harry
>>
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>
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