Re: TCP stalls in 2.0.33 and 2.1.x
Richard Gooch (rgooch@atnf.CSIRO.AU)
Wed, 18 Mar 1998 23:39:43 +1100
David S. Miller writes:
> Date: Wed, 18 Mar 1998 10:51:10 +1100
> From: Richard Gooch <rgooch@atnf.CSIRO.AU>
>
> OK, dump appended. Please let me know if there is anything else I
> can do. I got this output by doing:
>
> % tcpdump >& tcpdump.log
>
> This was on 2.1.76 (machine receiving data). The ftp host is
> running SunOS.
>
> This dump makes no sense, in your original report:
>
> I get reasonable performance with TCP, sending from machines on the
> LAN to machine A. However, most times when I send a large amount of
> random data (say 10000 bytes) from a LAN machine to machine B, I get
> TCP stalls. These stalls last for at least 15 minutes (I give up after
> that).
>
> And you dump shows (sans ARP packets etc. which I've edited out):
>
> 10:44:29.167467 130.155.194.32.ftp-data > jubemgee.atnf.CSIRO.AU.1030: S 2061632000:2061632000(0) win 4096 <mss 1460>
> 10:44:29.167646 jubemgee.atnf.CSIRO.AU.1030 > 130.155.194.32.ftp-data: S 3351443739:3351443739(0) ack 2061632001 win 32767 <mss 1460> (DF)
> 10:44:29.297544 130.155.194.32.ftp-data > jubemgee.atnf.CSIRO.AU.1030: . ack 1 win 4096
> 10:45:03.662022 jubemgee.atnf.CSIRO.AU.1030 > 130.155.194.32.ftp-data: F 1:1(0) ack 1 win 64240 (DF) [tos 0x8]
> 10:45:03.771359 130.155.194.32.ftp-data > jubemgee.atnf.CSIRO.AU.1030: . ack 2 win 4096
> 10:45:03.771532 jubemgee.atnf.CSIRO.AU.1030 > 130.155.194.32.ftp-data: R 3351443741:3351443741(0) win 0
>
> Not even one byte was transferred. And this shows a lot of TCP bugs
> which were present before pre90-3. Can I suggest you rerun your tests
> in the following way:
>
> 1) Do it with either 2.0.x latest or pre90-3, these we believe to have
> reasonably behaving TCP stacks.
>
> 2) When you trace the dumps, turn on tcpdump well before you do the
> transfers and perhaps add some arguments such as:
>
> tcpdump -i eth0 port 20
>
> (port 20 is FTP data, /etc/services is your friend)
>
> Then we can get down to buisness. From the dump you provided, there
> is nothing to diagnose ;-)
OK. I've done as you suggest, with 2.1.90 for machine B. Log
appended. Machine A is running 2.1.86 and the LAN ftp server is
running SunOS.
Regards,
Richard....
begin 644 tcpdump.log.gz
M'XL("."_#S4"`W1C<&1U;7`N;&]G`+V304O#0!"%[_D5<VP/+C.;9#>[2$&4
M@J="BR?QD#;;NC;9A&2K]=^;1)HHHH<6O,TR\+[WAK=^4V6'HM*0V\8;9]T.
M2@?&/V/`0QW&.B2&'%$JH!`9Q3$C%;&0LZVOKK+4IS"#E\/:%#MC6.K=EMVN
M[I<+=O/`"+G4L((8(QX+1-3#-,$IO%D'$2H!UT73`$4"9]^8)/$OY9;[BZ..
MR4.9"!4+DGH<.VJZV0^&J/<0<N+XQ01,[N;3T0G%B$ER;GK6`VD(V^N*5IJU
MLE+R<Q/.@32=\GS-T9F'1U\V@,?DZ81+6*14$B;_AA-$**++KL9_7*W7O:`7
MR[$7:NR%.K41@T!"U:*-;Z`V&V-?30;K=]C:W)LZP&&9U655?>[VIG8F#W+K
@#D=HRFZO85&9.O6V_4JN]-`^"NN]R3X`HCF52VX#````
`
end
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