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    SubjectRe: Slow start -- Linux vs. NT -- it's time to acknowledge the problem!
    Sooo... having the Windows-type person remove NetBEUI and Windows
    filesharing (SMB) would fix this if this is indeed the cause of problems?

    On Fri, 30 Nov 2001, Richard B. Johnson wrote:

    > On Fri, 30 Nov 2001, Jessica Blank wrote:
    >
    > > Hello esteemed kernel hackers:
    > >
    > > As you doubtless know, NT and BSD both have a broken slow-start
    > > implementation. As you may not know, when you try having a Linux box
    > > co-exist on a network with a Windows box, this seems to cause the Windows
    > > box to CROWD OUT the Linux box on the network.
    > >
    > > There is a fix to Solaris for this-- or a "workaround", I should
    > > say:
    > >
    > > http://www.sun.com/sun-on-net/performance/tcp.slowstart.html
    > >
    >
    > > THERE IS NO FIX TO LINUX FOR THIS. At least, not as far as I could
    > > find-- and I just got done Web-searching for a solid 15 minutes, finding
    > > MULTIPLE references to the Solaris workaround in the process.
    >
    > I seriouly doubt that your problem has anything to do with Linux, but
    > rather that the NT machines are set up to use Netbeui which puts
    > NETBIOS packets into broadcast packets. This means that all the data
    > to/from the M$ file-servers ends up being handled by your Ethernet board
    > and driver, then dumped onto the floor.
    >
    > A properly implimented IP Network minimizes the amount of broadcast
    > traffic. M$ tends to maximize it. Such a typical mess looks like
    > this:
    >
    > # tcpdump -n
    > 10:47:03.349550 10.110.128.209.138 > 10.111.255.255.138: udp 215
    > 10:47:03.349607 10.110.1.173.138 > 10.111.255.255.138: udp 216
    > 10:47:03.350618 10.110.129.85.138 > 10.111.255.255.138: udp 221
    > 10:47:03.351338 10.110.129.95.138 > 10.111.255.255.138: udp 213
    > 10:47:03.352340 10.110.1.152.138 > 10.111.255.255.138: udp 211
    > 10:47:03.352973 10.110.130.143.138 > 10.111.255.255.138: udp 212
    > 10:47:03.356839 10.110.130.53.138 > 10.111.255.255.138: udp 215
    > 10:47:03.359190 10.110.129.11.138 > 10.111.255.255.138: udp 217
    > 10:47:03.360571 10.110.129.47.138 > 10.111.255.255.138: udp 208
    > 10:47:03.361669 10.110.128.96.138 > 10.111.255.255.138: udp 215
    > 10:47:03.361938 10.110.129.51.138 > 10.111.255.255.138: udp 214
    > 10:47:03.363611 10.110.129.182.138 > 10.111.255.255.138: udp 213
    > ^C
    > #
    >
    > Here, data is being sent from a server 10.110.129.182, port 138
    > to a broadcast address, 10.111.255.255, port 138. Port 138 is
    > NETBIOS Datagram. So, all this data gets sent to every machine
    > on the LAN. It generates an interrupt, the driver gets the data
    > and passes it on. The IP stack looks at it and says "It ain't for
    > me...", and throws it away. This all takes CPU cycles that
    > Microsoft is stealing from you. The solution is to fire your
    > M$ administrator. Failing that, you need to get the fastest
    > Ethernet card, with a good fast driver. This allows the M$ data
    > to be thrown away without using too much of your CPU time.
    >
    > IP filtering in your machine doesn't do any good. It just adds
    > CPU cycles. The broadcast packets aren't for your machine anyway
    > so they are being rejected without any additional filter.
    >
    > Cheers,
    > Dick Johnson
    >
    > Penguin : Linux version 2.4.1 on an i686 machine (799.53 BogoMips).
    >
    > I was going to compile a list of innovations that could be
    > attributed to Microsoft. Once I realized that Ctrl-Alt-Del
    > was handled in the BIOS, I found that there aren't any.
    >
    >


    =========================================
    J e s s i c a L e a h B l a n k
    -----------------------------------------
    Programmer * Unix Sysadmin * Web Geek
    jessica@jessl.org -- cell@jessl.org
    -`-,-{@ http://www.jessl.org/ @}-,-`-
    =========================================


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