Date: Thu, 08 Nov 2007 17:40:58 +0100 From: Bram <bram@diomedia.be> To: Nikos Vassiliadis <nvass@teledomenet.gr>, freebsd-questions@freebsd.org Subject: Re: TCP/IP questions Message-ID: <47333C1A.7070709@diomedia.be> In-Reply-To: <200711081408.22387.nvass@teledomenet.gr> References: <4731E1A4.6020809@diomedia.be> <200711081408.22387.nvass@teledomenet.gr>
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Nikos Vassiliadis schreef: > On Wednesday 07 November 2007 18:02:44 Bram wrote: > >> Hi all, >> >> Can you change the timeout for a tcp connection ? >> I need to do the following: start a tcp connection , unplug the network >> cable (it's actually wifi but the effect is the same),send some data >> over the connection,wait 20 seconds , reinsert the network cable and >> just keep working. >> When you normally do this the connection will be dead. >> Is there a way in freebsd to change this ? are there parameters wich you >> can set so that the above would work (20 seconds without network can >> happen) ? >> > > TCP using the default FreeBSD settings, can survive > 20 secs of inactivity. It can be an application forced > timeout. What application/protocol are talking about? > > Nikos > This is the more full explanation: I have setup a mobile pc to roam across our building. By reducing the dwell time and changing the channel list to only the channels I use roaming now works within ten seconds en sometimes within one or two seconds. The previous configuration was with fedora and there I was unable to get roaming time under 25 seconds. I do have one very annoying problem however and I have no idea how to solve it. The software uses psycopg (a python postgresql module) wich uses the standard system parameters for connections (At least that is what I think). -On fedora if the connection gets lost and it takes 30 seconds to remake a new connection operation is not interupted, after the 30 seconds you get the data you've been waiting for. -On freebsd however we get it a lot that the connection is "lost", you can easily start a new connection wich works fine, but the old connection you wore using stops working and the app. hangs (If I had to guess I would say that roaming works about 95% of the time and the connection is lost about 5% of the time). I also get a lot of IFDOWN IFUP messages but this seems normal to me. I am now going to program something in twisted using udp to see if this works better. kind regards
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