Date: Fri, 23 Nov 2012 00:07:14 +0100 From: Ingo Flaschberger <if@xip.at> To: freebsd-net@freebsd.org Subject: Re: Low Bandwidth on intercontinental connections Message-ID: <50AEB022.6050608@xip.at> In-Reply-To: <50AE47D4.7080608@mpeters.org> References: <50ACF62C.8000408@mpeters.org> <CAOgwaMuUuJ2%2BmKqsFVp=DyVFkfm8Et%2Brnt2iEGDO8i1Kt_kDVA@mail.gmail.com> <50ad087d.1892cc0a.2cce.3bf2@mx.google.com> <50AD1012.7020209@mpeters.org> <50AD14F8.8050001@xip.at> <50ADE5E4.9090708@mpeters.org> <50AE0B12.8000309@xip.at> <50AE1CCC.7080706@mpeters.org> <50AE2686.8070007@xip.at> <50AE47D4.7080608@mpeters.org>
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> nearly every packet is fragmented, if i read th [TCP segment of a
> reassembled PDU] correct. Those have a length of 1364. Thera are also
> lots of [TCP Window Update] (every two to three acks from the receiving
> host, where the tcpdump took place). After some time, there were lots of
> [TCP Dup ACK] from the receiving host and the throughput went to a crawl
> and had lots of retransmissions. After 30 sec. everything went back to
> "normal" as of transmitting pakets without dubs and retransmissions.
how you can detect fragmented packets:
tcpdump at sender and at receiver site.
If you send 1500 byte packets but receive 2 differnt sized packets (a
bigger and a smaller one) at the other site - than there is fragmentation.
1364 packet length seems strage, as your
max icmp packet is 1322 byte + 20byte IP header + 8byte icmp = mtu 1350?
> The same tcpdump collect on the Linux hosts, the packets had a length of
> 1514 and no dubs or retransmissions.
1514? max mtu on ethernet is 1500
can you send me (directly) a send and receive site tcpdump from linux
and freebsd for a whole data-transfer?
Kind regards,
Ingo Flaschberger
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