[Serusers] TCP high load problems

[Klaus Darilion]

Hi Nils!

the problem is within sipp. I managed to capture the suspect TCP 
connection and sipp does send broken SIP messages when the TCP 
connection gets congested (window=0). I now use TLS as then the socket 
handling is done in openssl (not in sipp) which is probably more stable 
than the one in sipp. I guess there should not be much difference 
between TCP and TLS with NULL encryption (only a single TLS connection).

regards
klaus

Nils Ohlmeier wrote:
> Hi Klaus,
> 
> On Wednesday 26 July 2006 17:31, Klaus Darilion wrote:
>> Scenario: sipp sends INVITE to ser, ser replies with 404. sipp sends
>> 3000 INVITEs per second with TCP. sipp + ser on the same machine,
>> packets will be snet over loopback device.
>>
>> Suddenly ser reports a bad message:
>>
>> Jul 26 16:39:31 t4000 ser[14152]: ERROR:parse_first_line: method not
>> followed by SP
>>
>> Jul 26 16:39:31 t4000 ser[14152]: ERROR:parse_first_line: bad message
>>
>>   > rtpmap:0 PCMU/8000 087637 IN IP4 83.136.32.91sg:
>>
>> message=<p at 83.136.32.91:5066>;tag=6688
> 
> two things are coming to my mind:
> - the log output looks like their are nor CRLF in the SDP but only CR. Please 
> check with the hexoutput of ethereal how the lines and in this message, and 
> maybe in the last request before.
> - the content length if very important for TCP. If the content length of the 
> previous request is wrong SER would try read the next request from within the 
> SDP of the previous request (the one with the wrong content length). Could 
> you check the Content-Length is correct in the previous requests?
> 
> These are just two ideas. I do not blame any software yet ;-)
> 
>   Nils
> 
>> Jul 26 16:39:31 t4000 ser[14152]: ERROR: receive_msg: parse_msg failed
>>
>>
>> Although the message captured looks fine:
>>
>> INVITE sip:service at 83.136.32.91:5060 SIP/2.0
>> Via: SIP/2.0/TCP 83.136.32.91:5066;branch=z9hG4bK-6688-0
>> From: sipp <sip:sipp at 83.136.32.91:5066>;tag=6688
>> To: sut <sip:service at 83.136.32.91:5060>
>> Call-ID: 6688-14331 at 83.136.32.91
>> CSeq: 1 INVITE
>> Contact: sip:sipp at 83.136.32.91:5066
>> Max-Forwards: 70
>> Subject: Performance Test
>> Content-Type: application/sdp
>> Content-Length:  135
>>
>> v=0
>> o=user1 53655765 2353687637 IN IP4 83.136.32.91
>> s=-
>> c=IN IP4 83.136.32.91
>> t=0 0
>> m=audio 6002 RTP/AVP 0
>> a=rtpmap:0 PCMU/8000
>>
>>
>> Any hints for the problem debugging?
>>
>> thanks
>> klaus
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