Date: Tue, 19 Mar 2002 15:48:50 -0800 (PST) From: Doug White <dwhite@resnet.uoregon.edu> To: Aaron Baugher <abaugher@esc.pike.il.us> Cc: freebsd-stable@FreeBSD.ORG Subject: Re: Network stalls with 4.5 Message-ID: <20020319154511.L80289-100000@resnet.uoregon.edu> In-Reply-To: <m2vgbsifnj.fsf@haruchai.esc.pike.il.us>
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On 19 Mar 2002, Aaron Baugher wrote: > To add to the previous info, here's a chunk of a tcpdump. I logged in > through ssh, and ran 'top' to generate some traffic. My home machine > (Mandrake Linux, connected with a modem) is 11.22.33.44, and the > FreeBSD machine having the problem is 55.66.77.88. (I should stress > that the problem occurs from several different client machines and > OS's, so it's definitely caused at the server end.) This looks like simple packet loss on the network. Can you set up a monitor port on the Cisco switch and confirm the packet that is retried is actually making it onto the wire? Also set up other monitors downstream and see if you can isolate where the packet disappears. > 09:41:22.371874 55.66.77.88.22 > 11.22.33.44.4257: P 33324:33472(148) ack 161 win 65535 [tos 0x10] > 09:41:23.371716 55.66.77.88.22 > 11.22.33.44.4257: P 33324:33472(148) ack 161 win 65535 [tos 0x10] > > That's the same packet sent twice, right? > > 09:41:24.381831 55.66.77.88.22 > 11.22.33.44.4257: P 33472:33628(156) ack 161 win 65535 [tos 0x10] > 09:41:24.629822 11.22.33.44.4257 > 55.66.77.88.22: . ack 33324 win 51360 (DF) [tos 0x10] > 09:41:25.371763 55.66.77.88.22 > 11.22.33.44.4257: P 33324:33628(304) ack 161 win 65535 [tos 0x10] > > Now here's the same number (33324) as the doubled packet above, but > with a different second number and size. The change in size is the system gluing the payloads of the two packets together since the remote sent an ACK up to 33324. > 09:41:34.666565 11.22.33.44.4257 > 55.66.77.88.22: . ack 33324 win 51360 (DF) [tos 0x10] > 09:41:34.666621 55.66.77.88.22 > 11.22.33.44.4257: P 33324:34336(1012) ack 161 win 65535 [tos 0x10] > 09:41:35.147334 11.22.33.44.4257 > 55.66.77.88.22: . ack 34336 win 51360 (DF) [tos 0x10] Look like your network keeled over for 10 seconds. Bandwidth problems downstream? Also make sure something downstream isn't, say, loosing the ARP entry for it's default gateway. Doug White | FreeBSD: The Power to Serve dwhite@resnet.uoregon.edu | www.FreeBSD.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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