[Serdev] TCP problems

[Katty Xiong]

Hi Klaus,

I use sipp-1.1rc8. The version seems fixed the problem
you mentioned. I didn't observe any broken SIP message
sent by SIPp.

The problem seems: 
With high load, one cpu @ SER is saturated, TCP @ SER
have 0 receiver window first. When SER has 0 receiver
window, SIPp UAC couldn’t send anything and stucks
somewhere in the send() function, so it couldn’t
receive anything. As a result, TCP @ SIPp has zero
receive window finally, and TCP @ SER has zero sending
window as a result.

I couldn't understant why the non-blocking send in
SIPp blocks when SER close its TCP window.

Thanks,
Joy

--- Klaus Darilion <klaus.mailinglists at pernau.at>
wrote:

> Hi!
> 
> I had similar problems when testing TCP performance.
> When the TCP window 
> is set to 0, sipp corrupted a buffer and sent broken
> SIP messages. AFAIK 
> this is fixed in CVS version.
> 
> Thus, before looking for bugs in ser make sure to
> use the newest sipp 
> (which still might have some bugs).
> 
> regards
> klaus
> 
> 
> Katty Xiong wrote:
> > Hi, 
> > 
> > I am using SER (Ottendorf) and SIPp for some
> > performance study and get several errors when
> using
> > TCP protocol. From the packet trace, I notice when
> TCP
> > publicize zero window at SIPp or SER side, SIP
> message
> > will get truncated or several partial or whole SIP
> > message get combined in one TCP packet, which
> leads to
> > error. I haven’t checked the code yet, but if
> somebody
> > already knows this off the head, please clarify me
> of
> > the following questions.
> > 1) When SER receives a truncated SIP message, how
> does
> > it handle the partial message? 
> > 2) When SER receives a packet that has one partial
> SIP
> > message combined with another partial SIP message,
> how
> > does it handle the packet?
> > 3) When SER receives several SIP messages in one
> TCP
> > packet, how does it handle the packet?
> > 4) Does SER care how TCP send one SIP message (in
> > several TCP packets, combined with other SIP
> > messages)?
> > 
> > I joined the alias recently, so if the alias
> already
> > had discussions on TCP stream behavior and its
> effects
> > on SER implementation, could somebody point the
> link
> > to me?
> > 
> > Thanks,
> > Joy
> > 
> > 
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> 
> 
> -- 
> Klaus Darilion
> nic.at
> 
> 



 
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