Low performance rate between ssh nodes - SSH

This is a discussion on Low performance rate between ssh nodes - SSH ; Hi, I have a wired problem with ssh and no idea how to analyze the problem. So every hint is appreciated inlcuding the hint to another newsgroup. Here the configuration of the 4 computers which I used pc83 (OpenSSH_3.8.1p1 Debian-8.sarge.6, ...

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Thread: Low performance rate between ssh nodes

  1. Low performance rate between ssh nodes

    Hi, I have a wired problem with ssh and no idea how to analyze the problem.
    So every hint is appreciated inlcuding the hint to another newsgroup.

    Here the configuration of the 4 computers which I used
    pc83 (OpenSSH_3.8.1p1 Debian-8.sarge.6, OpenSSL 0.9.7e 25 Oct 2004) a PC
    which could only have an outgoing ssh connection, so I initialized
    a tunnel from there to one of the next 2 notebooks. The connection is via
    DSL/Internet

    tine an older notebook Intel Celeron 184 Mhz
    OpenSSH_3.8.1p1 Debian-8.sarge.6, OpenSSL 0.9.7e 25 Oct 2004
    inside local network.

    onnie a newer notebook Intel Celeron 547 MHz
    OpenSSH_4.3p2 Debian-9, OpenSSL 0.9.8c 05 Sep 2006
    inside local network.

    pondus a workstation in my local network
    OpenSSH_3.8.1p1 Debian-8.sarge.6, OpenSSL 0.9.7e 25 Oct 2004


    The connection between all runs over an DSL-Internet-Router.

    Now I copy an mp3-file to measure the network rate.
    Here the result (Please don't be amazed about the localhost, it is a
    scp-connection through an ssh-tunnel for technical reasons).

    Copy the file from pc83 to onnie (Very SLOW!)
    niels@onnie:~$ scp -P50022 localhost:dlf/DLF_FuT_30-10-2007.mp3 .
    DLF_FuT_30-10-2007.mp3 100% 10MB 18.0KB/s 09:56

    Copy the file from pc83 to tine (Acceptable Rate 6 times faster)
    niels@tine:~$ scp -P50022 localhost:dlf/DLF_FuT_30-10-2007.mp3 .
    DLF_FuT_30-10-2007.mp3 100% 10MB 124.4KB/s 01:26

    To I thought there must be a network configuration or hardware problem at
    onnie. But than I measured the rate between onnie/tine and my workstation
    pondus. Here the result:
    niels@pondus:/tmp$ scp onnie:dlf/DLF_FuT_29-10-2007.mp3 .
    DLF_FuT_29-10-2007.mp3 100% 11MB 987.2KB/s 00:11
    niels@pondus:/tmp$ scp tine:dlf/DLF_FuT_29-10-2007.mp3 .
    DLF_FuT_29-10-2007.mp3 100% 11MB 434.4KB/s 00:25

    So this time is tine a little bit slower, perhaps here is the slower cpu the
    reason. Anyway the network configuration or hardware could not be the
    problem.

    So are the different SSH-version the reason? Or what else could it be?

    Thanks for reading this long description. Last hint: all measurement was
    made more than onetime and the result was allways the same.
    Niels





  2. Re: Low performance rate between ssh nodes

    On 2007-10-31, Niels Stargardt wrote:

    > Now I copy an mp3-file to measure the network rate.
    > Here the result (Please don't be amazed about the localhost, it is a
    > scp-connection through an ssh-tunnel for technical reasons).


    Have you got measurements not involving ssh for comparison?

    Is compression turned on? Applying compression multiple times
    to am mp3 file is likely to be an unrewarding experience.

    --
    Elvis Notargiacomo master AT barefaced DOT cheek
    http://www.notatla.org.uk/goen/

  3. Re: Low performance rate between ssh nodes

    Hi thanks for the answer:
    >
    >> Now I copy an mp3-file to measure the network rate.
    >> Here the result (Please don't be amazed about the localhost, it is a
    >> scp-connection through an ssh-tunnel for technical reasons).

    >
    > Have you got measurements not involving ssh for comparison?
    >
    > Is compression turned on? Applying compression multiple times
    > to am mp3 file is likely to be an unrewarding experience.
    >

    Well I turned compression off and indeed the performance increase, but at
    onnie it was still bad.
    I made than another test. I copied the file to an public server in the same
    net where pc83 stands. I get than the same problem. So it seems that it has
    nothing to do with ssh.
    The interesting point is that the problem occurs only for connection to my
    company. If I try to download via wget the kernel source everything is
    fine. BTW No firewall is installed on both notebooks. So it looks that this
    is a wired network problem - so I'm in the wrong newsgroup.

    Thank for the help and have a nice time.

    Niels


  4. Re: Low performance rate between ssh nodes

    Niels Stargardt schrieb:
    > Hi thanks for the answer:
    >>> Now I copy an mp3-file to measure the network rate.
    >>> Here the result (Please don't be amazed about the localhost, it is a
    >>> scp-connection through an ssh-tunnel for technical reasons).

    >> Have you got measurements not involving ssh for comparison?
    >>
    >> Is compression turned on? Applying compression multiple times
    >> to am mp3 file is likely to be an unrewarding experience.
    >>

    > Well I turned compression off and indeed the performance increase, but at
    > onnie it was still bad.
    > I made than another test. I copied the file to an public server in the same
    > net where pc83 stands. I get than the same problem. So it seems that it has
    > nothing to do with ssh.
    > The interesting point is that the problem occurs only for connection to my
    > company. If I try to download via wget the kernel source everything is
    > fine. BTW No firewall is installed on both notebooks. So it looks that this
    > is a wired network problem - so I'm in the wrong newsgroup.


    despite the reason of your problem:
    instead of tunneling ssh over ssh, its faster to use nc (netcat) as
    forwarding tunnel.
    Wolfgang

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