[Asterisk-Dev] Henning G. Schulzrinne quote on IAX2 from von magazine

John Todd jtodd at loligo.com
Sat Aug 13 13:55:46 MST 2005


At 1:56 PM -0500 on 8/13/05, Brian West wrote:
>On Aug 13, 2005, at 1:45 PM, John Todd wrote:
>
>>I hereby kill this thread and take it to the -users list.
>>
>
>
>Actually this should be on -dev because IAX2 does have scalability 
>issues.  It will not and CAN NOT scale to large scales.  This is due 
>to the single thread that handles all traffic in and out of the 
>single UDP port.  As you start to load the box with calls the call 
>quality starts to degrade and the delay shoots thru the roof.  You 
>have one queue for receive and one for transmit that is serviced by 
>the same thread.  Now if you pile on 30 calls with say a 300ms of 
>latency it starts to sound like crap while running sip in the same 
>situation sounds perfect.  IAX2 has its place but not in a large 
>scale deployment at this time unless we can solve the issue with the 
>bottle neck in the tx/rx queues.  I think we have talked about 
>splitting the tx and rx queues into two threads that only gains a 
>little bit of speed.  The next step would be to move this operation 
>into the kernel since it does this and does it well already.  Then 
>again on the other hand if you had an option to use a dedicated udp 
>port per call that would also cause the issue to go away.  We could 
>add something to punch thru nat and cause it to work just like it 
>does now without much if any thought on the users side.
>
>/b

err.... was that mentioned in the previous thread?   This is a 
non-sequitur referring to some other bug, and should have a thread 
title change, but I'll leave that up to you.

I agree that your comments reference a -dev issue, but is 
implementation specific to Asterisk and does not reference the 
discussion prior to this point.  This is not an IAX2 issue, this is 
an Asterisk issue.

JT



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