RE: [lwip-users] Lwip 1.3.0 Running out of TCP PCB's fast

[B B]

Hi Jim,
 
Thanks for your answer.
 
@Jonathan: Indeed i was just speculating whether it was an real error or not.
Maybe that count should be removed, if a pcb is reused.
 
best regards,
Martin

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> Date: Wed, 27 Aug 2008 15:06:48 +0100
> From: address@hidden
> To: address@hidden
> Subject: Re: [lwip-users] Lwip 1.3.0 Running out of TCP PCB's fast
>
> Pettinato, Jim wrote:
> > This is due to pcbs being placed in a TIME_WAIT state; i.e. when you
> > close a connection they're not really freed yet, they're hanging around
> > waiting for enough time to pass to make sure no stray packets come in
> > and screw up a future connection. Note that the default 'enough time' is
> > like two hours, so an automatically refreshing web page will eat up pcbs
> > very quickly. (This is TCP standard behavior as defined in the RFQs,
> > though it makes little sense in today's high-speed networks.)
> >
> > Even though the error count gets incremented, lwIP will (upon finding no
> > free pcbs) allocate a pcb from the TIME_WAIT list and use it, so this
> > may not actually be a problem for your implementation.
>
> Ahh, while I knew about TIME_WAIT and lwIP reusing them, I didn't remember
> it would increment the error count anyway, and I assumed B B was saying an
> allocation had failed, corroborated by the error count. So yes, hopefully B
> B was only speculating and not reporting a problem.
>
> Jifl
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