nanog mailing list archives
RE: TCP congestion
From: "Brian Knoll \(TTNET\)" <Brian.Knoll () tradingtechnologies com>
Date: Thu, 12 Jul 2007 15:48:41 -0500
Are you using TCP offloading on your windows box? I have seen issues with that in the past where it was dropping data. Turn it off and see if the issue goes away. Are other the other connections traversing this path seeing the same issues? Still - the only definitive way to solve the problem is by getting captures from both ends. If you can isolate your wan with taps on each side and see packets being dropped, you know it's your ATM circuit. QOS will not help you if you aren't exceeding bandwidth. Thanks, Brian Knoll Senior Network Engineer, TTNET 312-698-6017 desk 312-823-0957 mobile -----Original Message----- From: owner-nanog () merit edu [mailto:owner-nanog () merit edu] On Behalf Of Philip Lavine Sent: Thursday, July 12, 2007 3:28 PM To: Stephen Wilcox Cc: nanog Subject: Re: TCP congestion I just don't understand how if there is 1 segment that gets lost how this could translate to such a catastrophic long period of slow-start. How can I minimize the impact of the inevitable segment loss/out of order over a WAN. Is QoS the only option? ----- Original Message ---- From: Stephen Wilcox <steve.wilcox () packetrade com> To: Philip Lavine <source_route () yahoo com> Cc: nanog <nanog () merit edu> Sent: Thursday, July 12, 2007 1:09:24 PM Subject: Re: TCP congestion Well, if its out of order its the same as if its lost or delayed, it needs to see that missing segment before the window is full As mentioned you need to get dumps from both ends, you will almost definitely find that you have packet loss which tripped tcp's slow start mechanism. Steve On Thu, Jul 12, 2007 at 12:02:49PM -0700, Philip Lavine wrote:
Even if the segment was received out of order what would cause
congestion avoidance to starve the connection of legitimate traffic for 15 to 20 seconds? That is the core of the problem.
----- Original Message ---- From: Fred Baker <fred () cisco com> To: Brian Knoll <Brian.Knoll () tradingtechnologies com> Cc: Philip Lavine <source_route () yahoo com>; nanog <nanog () merit edu> Sent: Thursday, July 12, 2007 11:56:06 AM Subject: Re: TCP congestion On Jul 12, 2007, at 11:42 AM, Brian Knoll ((TTNET)) wrote:If the receiver is sending a DUP ACK, then the sender either never received the first ACK or it didn't receive it within the timeframe
it
expected.or received it out of order. Yes, a tcpdump trace is the first step.
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Current thread:
- Re: TCP congestion, (continued)
- Re: TCP congestion Fred Baker (Jul 12)
- Re: TCP congestion Jared Mauch (Jul 12)
- Re: TCP congestion Valdis . Kletnieks (Jul 12)
- RE: TCP congestion michael.dillon (Jul 12)
- Re: TCP congestion Joe Loiacono (Jul 12)
- Re: TCP congestion Jay Hennigan (Jul 12)
- Re: TCP congestion Warren Kumari (Jul 13)
- Re: TCP congestion Philip Lavine (Jul 12)
- Re: TCP congestion Stephen Wilcox (Jul 12)
- Re: TCP congestion Philip Lavine (Jul 12)
- RE: TCP congestion Brian Knoll (TTNET) (Jul 12)
- Re: TCP congestion Iljitsch van Beijnum (Jul 12)
- Re: TCP congestion Stephen Wilcox (Jul 12)
- Re: TCP congestion Kevin Loch (Jul 12)
- Re: TCP congestion Joel Jaeggli (Jul 12)
- Re: TCP congestion Leigh Porter (Jul 12)