[asterisk-users] Improving the voice Quality,

Steve Totaro stotaro at totarotechnologies.com
Fri Oct 3 21:36:44 CDT 2008


BT3 (BackTrack) LiveCD is one of the best things out there, even has sipp
built right in, as well as other great apps, utilities, and security
"auditing".

I suggest everyone have a copy in their arsenal, and it is free of course.

Thanks,
Steve Totaro

On Fri, Oct 3, 2008 at 10:09 PM, Jai Rangi <jprangi at gmail.com> wrote:

> All,
>
> Just an update on this. This turned out to be a bug in Cisco firewall. We
> ended up in upgrading the Firmware on the firewall.
>
> One thing I want to add, this was first time we used the fail over unit
> during peak time. In the whole process (failover, upgrade and failover back
> to active unit) was completely seamless. Did not had any down time, there
> was just a pause for just 1 second in the audio. I was very impressed.
>
> -Jai
>
>
>
> On Fri, Oct 3, 2008 at 1:21 PM, Jai Rangi <jprangi at gmail.com> wrote:
>
>> Oh yes, how could I forgot about that?
>> Thank you,
>>
>> -Jai
>>
>>
>>
>> On Fri, Oct 3, 2008 at 1:08 PM, Alex Balashov <abalashov at evaristesys.com>wrote:
>>
>>> sipp can simulate RTP traffic.
>>>
>>> Jai Rangi wrote:
>>>
>>> > Al and Alex,
>>> > Thank you for your input,
>>> > Sorry TDM is not the option at this time :( .
>>> > Everything has been great until last 2-3 days. Machine loads is not the
>>> > issue, we have multiple asterisk server to share the load. Not much
>>> > change in traffic.
>>> >
>>> > Now it been narrowed down to networking and we are trying to find out
>>> > where the issue is?  In our Firewall or SP's router. Does any one know
>>> > of any tool to simulate RTP traffic. Its pain to find out the bad calls
>>> > out of hundreds of calls.
>>> > BTW, What should be right value for tos in sip.conf.
>>> > We have
>>> > tos=0x68
>>> > Dont remember how did I come up with this value.
>>> >
>>> > I found this
>>> > http://www.voip-info.org/wiki/index.php?page=Asterisk+sip+tos
>>> >
>>> > tos=0x10      low delay
>>> > tos=0x08      high throughput
>>> > tos=0x04      high reliability
>>> > tos=0x02      ECT bit set
>>> > tos=0x01      CE bit set
>>> >
>>> >
>>> > -Jai
>>> >
>>> >
>>> > On Fri, Oct 3, 2008 at 4:58 AM, Al Baker <bwentdg at pipeline.com
>>> > <mailto:bwentdg at pipeline.com>> wrote:
>>> >
>>> >     USE TDM Circuits - Voice Quality Good
>>> >
>>> >     Alex Balashov wrote:
>>> >      > Jai Rangi wrote:
>>> >      >
>>> >      >
>>> >      >> All,
>>> >      >>
>>> >      >> I am having audio quality problem in some calls (1-2%) on
>>> >     asterisk. I
>>> >      >> captured RTP traffic using ethereal and this is what I found
>>> >     with the
>>> >      >> problematic calls. (Worst cases)
>>> >      >> Drop by Jitter buff: 25-75%
>>> >      >> Out of Seq: 50-100% (100 % means very very poor call quality).
>>> >      >>
>>> >      >> Has anyone had similar problem? If yes, can you please share
>>> your
>>> >      >> experience on how did you fix this?
>>> >      >>
>>> >      >
>>> >      > Such poor performance is not fixable.  The network, connectivity
>>> >     issues,
>>> >      > machine load, etc. needs to be addressed - the underlying cause,
>>> in
>>> >      > other words.
>>> >      >
>>> >      > BTW, 100% out-of-sequence RTP packets leads to a lot more than
>>> just
>>> >      > "very very poor call quality."  I don't see how the conversation
>>> >     could
>>> >      > even be coherent in that situation.
>>> >      >
>>> >      > What is more likely is that Wireshark's RTP stats are giving you
>>> some
>>> >      > distorted information.  I've found its stream analysis to be
>>> somewhat
>>> >      > buggy in that regard.
>>> >      >
>>> >      >
>>> >      >> I was wondering if I can decrease the MTU size to 250-500 on
>>> the
>>> >     network
>>> >      >> card and use that card only for VoIP traffic. Will this have
>>> any bad
>>> >      >> effect on sip traffic/packets?
>>> >      >>
>>> >      >
>>> >      > No.  RTP packets are very small - much smaller than that MTU, or
>>> any
>>> >      > reasonable MTU you could set.
>>> >      >
>>> >      >
>>> >
>>> >     _______________________________________________
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>>> >
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>>> >
>>> >
>>> >
>>> >
>>> ------------------------------------------------------------------------
>>> >
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>>>
>>> --
>>> Alex Balashov
>>> Evariste Systems
>>> Web    : http://www.evaristesys.com/
>>> Tel    : (+1) (678) 954-0670
>>> Direct : (+1) (678) 954-0671
>>> Mobile : (+1) (706) 338-8599
>>>
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>>
>>
>
> _______________________________________________
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>
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-- 
Thanks,
Steve Totaro
+18887771888 (Toll Free)
+12409381212 (Cell)
+12024369784 (Skype)
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