[Asterisk-Users] Distortion/crackling/skipping
problems on outgoing calls -- please help!!!
Robert Geller
robert at worksofmagic.com
Sat Sep 3 21:21:03 MST 2005
Robert Geller wrote:
> Rich Adamson wrote:
>
>>>>
>>>>
>>>>
>>>
>>> Thank you very much for your response. I do acknowledge that my
>>> previous posts did not contain much technical information to speak
>>> of, but it was mainly because I wasn't/am not familiar with the
>>> Asterisk CLI and troubleshooting Asterisk problems, so I apologize
>>> for that.
>>>
>>> I did get the idea early this morning to try to analyze packets with
>>> ethereal, and I captured packets when I was made an internal IAX
>>> call to the Asterisk system (voicemail). I don't really know what to
>>> look for, but I will learn (again, I'm not very familiar with
>>> ethereal). Do you hapeople say ve any suggestions for filters to
>>> use, to evaluate possible packet loss or resending of data?
>>>
>>
>>
>> An important item to look at in each packet is the timestamp. In sip
>> packets, the timestamp should be increasing by 160 for each conseq pkt.
>> In iax packets, the timestamp should be increasing by 20 for each pkt.
>>
>> So if you see a timestamp of 3290 in one pkt and 3310 in the next (a
>> diff
>> of 20), that's good. Notice the increasing timestamp value and the diff.
>> If pkt 3310 arrives before 3290, then something in the network is
>> delaying
>> the delivery of packets so as to cause them to not arrive in the proper
>> order.
>>
>> If there are missing packets, then you'll see timestamps jumping by 40,
>> 60, 80 or some other value (diff) for iax packets, or, similar for sip
>> packets.
>>
>>
>>
>>> Regarding the command that you suggested in the CLI, iax2 show
>>> netstats, it doesn't recognize that command or anything similar, and
>>> 'help' doesn't return anything similar that I can see (I'm using
>>> 1.0.7 if that helps).
>>>
>>
>>
>> Since 1.0.7 is rather old (in the scheme of things), I'd suggest you
>> install something newer to play with. There has been a ton of stuff
>> that has changed since 1.0.7, but I don't recall if those changes would
>> have anything to do with your problem. (I use nothing but cvs head, but
>> I kind of keep an eye on how many changes are happening (and for what
>> reason), and upgrade when the number of problems seem to be at a low.
>> The 'iax2 show netstats' would have been added in a later version.
>>
>>
>>
>>> At this point, I'm thinking that it could be a matter of bad cabling
>>> or something. The Cat5 cable that's running the 8 or so feet from my
>>> PC to my router is homemade by me, and many people do report
>>> problems with homemade cables. I may not have made it exactly right,
>>> or the untwisted segment may be longer than 1/2", which supposedly
>>> causes distortion and interference. Perhaps I ought to run out and
>>> buy a couple factory-made cables to test the difference, if any,
>>> between them.
>>>
>>
>>
>> Replacing the cable would probably be a good start since they are
>> relatively cheap. Go buy a new one so there's no question about its
>> quality. Also, keep the cable at least a little distance away from
>> transformers, ballasts, and other things that tend to generate tons
>> of electical noise. (Some desk lamps even have extremely noisy
>> transformers
>> or ballasts in them.)
>>
>>
>> _______________________________________________
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>>
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>>
>>
>>
>>
> Your advice was *extremely* helpful. It seems that I learn something
> new each time I read you all's posts. To me, it looked like each
> packet was correctly sent at the right interval each time, but I
> didn't evaluate each one. However, the general trend is that there
> seems to be no packet loss or resending.
>
> I could buy another cable as well, just to be safe, but it seems to me
> the potential IRQ conflict is more the more likely problem--of course,
> even when I "ifconfig eth2 down"ed the interface, it still showed up
> in /proc/interrupts -- does bringing the interface down not completely
> bring it down? Should I permanently disable it and reboot?
>
> Again, thank you very much for your ongoing help; I feel like I'm
> paying (or ought to) for professional support here. :-)
>
> Regards,
> Robert Geller
> _______________________________________________
> --Bandwidth and Colocation sponsored by Easynews.com --
>
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>
>
I modprobe -r'ed prism54, the wireless kernel modules for my card, and
here's what /proc/interrupts looks like:
robert at linux:~/torrents$ cat /proc/interrupts
CPU0
0: 81981003 IO-APIC-edge timer
1: 49755 IO-APIC-edge i8042
7: 2 IO-APIC-edge parport0
8: 1 IO-APIC-edge rtc
9: 0 IO-APIC-level acpi
12: 499429 IO-APIC-edge i8042
14: 224679 IO-APIC-edge ide0
15: 900392 IO-APIC-edge ide1
169: 0 IO-APIC-level uhci_hcd
177: 67917 IO-APIC-level Intel 82801BA-ICH2
185: 0 IO-APIC-level uhci_hcd
193: 2 IO-APIC-level ohci1394
201: 2020679 IO-APIC-level eth0
NMI: 0
LOC: 81991943
ERR: 0
MIS: 0
Well, eth2 isn't even on there, let alone being shared with that Intel
device. Still, however, the softphone sounds just as bad. Who would have
thought it was a coincidence that there was IRQ sharing/conflicts going
on, yet that isn't the soure of my problem?
I'm stumped. I even tried moving the power/surge strip farther away from
the computer, but it can't be too far away, about 18 inches-2 feet now.
So, 1) there doesn't *seem* to be any packet loss or incorrect packet
sending, 2) there are no more IRQ conflicts, and 3) I even tried moving
my power strip away from the PC. What gives?
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