[Serusers] TCP high load problems

Hi! 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 message=<p@83.136.32.91:5066>;tag=6688 Jul 26 16:39:31 t4000 ser[14152]: ERROR: receive_msg: parse_msg failed Although the message captured looks fine: INVITE sip:service@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@83.136.32.91:5066>;tag=6688 To: sut <sip:service@83.136.32.91:5060> Call-ID: 6688-14331(a)83.136.32.91 CSeq: 1 INVITE Contact: sip:sipp@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