[Asterisk-Users] Strange Quality problems with Asterisk, Gentoo, Redhat and Kernels - /dev/dsp

[Deon Rodden]

Does /dev/dsp exist for you? What are you using for zaptel timing?

Duane Cox wrote:

> For what it's worth, I'm using linux-2.4.27 kernel built with gcc-3.3.4
> and glibc-2.3.3  and everything is completely fine...  totaly custom 
> distro.
>
> Duane Cox
>
> ----- Original Message ----- From: "Deon Rodden" <drodden at webunited.net>
> To: <asterisk-users at lists.digium.com>
> Sent: Wednesday, September 29, 2004 9:56 AM
> Subject: [Asterisk-Users] Strange Quality problems with Asterisk, 
> Gentoo, Redhat and Kernels - /dev/dsp
>
>
>> I've compiled Asterisk on Redhat 9 and Fedora Core 1 in the past, 
>> generally without any problems. Especially w/ the stock kernel, which 
>> I generally loathe. When I tried to upgrade my Redhat 9 Server to the 
>> 2.4.27 kernel, doing a manual/clean compile, I had massive quality 
>> issues. I was forced to go back down to a stock 2.4.24 kernel. Never 
>> figured out why.
>>
>> Now, I've installed Gentoo and am using the 2.4.26 kernel, and things 
>> initially appeared ok. I emerge'd Asterisk, the dependencies were 
>> downloaded compiled, Asterisk 0.9.0 was compiled, I then used cvs to 
>> update to the latest libpri/zaptel/asterisk. Everything seemed fine. 
>> However, I'm noticing the occasional quality issue. First I just 
>> thought the music on hold was a little choppy, but that always seems 
>> normal, I blamed the zaprtc/rtcsetup thing I'm using to get zaptel 
>> timing.
>>
>> But then we noticed problems with Grandstream phones. The grandstream 
>> would connect to the Gentoo Asterisk Server via SIP, then go out via 
>> IAX across a T1 to the main asterisk server (Redhat 9), which then 
>> pushes the call via SIP to a Cisco Router that's connected to several 
>> PRI's. My last clue therem ay be a problem with Gentoo is the T1 card 
>> we put in another server. We put a T100P in another Gentoo server, 
>> therefore didn't need zaprtc/rtcsetup, and it uses pri-net to 
>> simulate a Voice T1 PRI for a PBX system. Calls will come in via 
>> IAX2, from my main asterisk server, and it will then (using Zap) go 
>> out the T100P into the PBX. There's an intermittant quality issue 
>> there as well.
>>
>> The only clues in the log files was something about /dev/dsp missing. 
>> This didn't seem a big deal, music on hold worked, etc. but I noticed 
>> that /dev/dsp existed on my redhat machines, even though they're the 
>> same servers, no sound cards or anything. The kernel on the Redhat 
>> machines was compiled with several sound card modules, but nothing 
>> integrated. An 'lsmod' reveals a module called soundcore loaded, but 
>> I can't find soundcore on my Gentoo machines.
>>
>> Is there anything mandator in the compilation of the kernel that will 
>> affect Asterisk's quality? The CPU load on the systems is nothing. 
>> Everything "appears" normal. The only common factor is custom 
>> compiled kernel. A custom compiled 2.4.27 on Redhat had problems, and 
>> a Custom Compiled 2.4.26-gentoo on Gentoo has not-so-apparent 
>> problems too.  I've always been on top of the latest CVS updates on 
>> Zaptel/Asterisk/libPRI
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>
> .
>