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Jeff 08-24-2011 12:15 PM

SSH Compression
 
Hi all,
I don't have easy access to a server at the minute, and not sure where the settings are anyway; but I've been wondering about this for a while and am just hoping that someone can point me in the right direction:
A week or so ago when I was onsite at a school, I ran a binary tcpdump to get an indication of network usage with approximately 12 thin clients working.
It wasn't a very precisely measured test or anything, but the server sent/received a Gigabyte of traffic in about a couple of minutes.
So I'm just wondering whether SSH compression is enabled by default or not? And if it is, whether there's any way to tweak it?
Also, it occurs to me that SSH compression would have to be lossless, by nature. So I'm wondering if there's any way to get something like tight-vnc working; or whether we should try a lightweight X desktop like XFCE?
I'm not really happy about the performance, compared to terminal server, for ex, or even the old Fedora/Gnome K12-LTSP we upgraded from.
Insights and pointers appreciated. Flames > /dev/null
;-)
--Jeff Brown
Tel:+27-74-101 5170Fax:+27-86-532 3508www.wildcoast.co.za

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David Groos 08-24-2011 01:24 PM

SSH Compression
 
Hey Jeff, Sounds like you are looking for good gui remote access over
ssh? I use FreeNX as the server and use NoMachine's client and
now also use OpenNX since it works well with lion-10.7.* The access over
broadband internet is just like sitting at the computer--works great to
manage remote servers running Edubuntu/ltsp.* I hear it is even a decent experience over dial-up.* So, while I don't know what the compression is, it must be pretty good to work this well in this situation.* If you have more
questions, let me know.

David

On Wed, Aug 24, 2011 at 7:15 AM, Jeff <jeff@wildcoast.com> wrote:

Hi all,
I don't have easy access to a server at the minute, and not sure where the settings are anyway; but I've been wondering about this for a while and am just hoping that someone can point me in the right direction:

A week or so ago when I was onsite at a school, I ran a binary tcpdump to get an indication of network usage with approximately 12 thin clients working.
It wasn't a very precisely measured test or anything, but the server sent/received a Gigabyte of traffic in about a couple of minutes.

So I'm just wondering whether SSH compression is enabled by default or not? And if it is, whether there's any way to tweak it?
Also, it occurs to me that SSH compression would have to be lossless, by nature. So I'm wondering if there's any way to get something like tight-vnc working; or whether we should try a lightweight X desktop like XFCE?

I'm not really happy about the performance, compared to terminal server, for ex, or even the old Fedora/Gnome K12-LTSP we upgraded from.
Insights and pointers appreciated. Flames > /dev/null

;-)


--Jeff Brown
Tel:+27-74-101 5170
Fax:+27-86-532 3508www.wildcoast.co.za




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Jeff 08-29-2011 10:10 AM

SSH Compression
 
Thanks for the input, David.
Still getting my head around *NX. Can the client work from the thin-clients without loading a windowing system?
In the meantime, I found this article*http://ubuntuforums.org/archive/index.php/t-368869.html about compression.
Looking around the configuration files I don't see any compression enabled in*/var/lib/tftpboot/ltsp/i386/lts.conf so I've added:
## SSH compression between LTSP client and serverNETWORK_COMPRESSION = True*
remotely, but haven't been onsite to test it yet.
/var/lib/tftpboot/ltsp/i386/config-2.6.38-8-generic has several compression parameters, but nothing explicitly about SSH from what I can see.
Will post an update when I've had a chance to test.
Cheers,
Jeff



On 24 Aug 2011, at 3:24 PM, David Groos wrote:Hey Jeff, Sounds like you are looking for good gui remote access over ssh? I use FreeNX as the server and use NoMachine's client and now also use OpenNX since it works well with lion-10.7.* The access over broadband internet is just like sitting at the computer--works great to manage remote servers running Edubuntu/ltsp.* I hear it is even a decent experience over dial-up.* So, while I don't know what the compression is, it must be pretty good to work this well in this situation.* If you have more questions, let me know.
David

On Wed, Aug 24, 2011 at 7:15 AM, Jeff <jeff@wildcoast.com> wrote:
Hi all,
I don't have easy access to a server at the minute, and not sure where the settings are anyway; but I've been wondering about this for a while and am just hoping that someone can point me in the right direction:
A week or so ago when I was onsite at a school, I ran a binary tcpdump to get an indication of network usage with approximately 12 thin clients working.
It wasn't a very precisely measured test or anything, but the server sent/received a Gigabyte of traffic in about a couple of minutes.
So I'm just wondering whether SSH compression is enabled by default or not? And if it is, whether there's any way to tweak it?
Also, it occurs to me that SSH compression would have to be lossless, by nature. So I'm wondering if there's any way to get something like tight-vnc working; or whether we should try a lightweight X desktop like XFCE?
I'm not really happy about the performance, compared to terminal server, for ex, or even the old Fedora/Gnome K12-LTSP we upgraded from.
Insights and pointers appreciated. Flames > /dev/null
;-)
--Jeff Brown
Tel:+27-74-101 5170 Fax:+27-86-532 3508www.wildcoast.co.za


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Jeff 08-29-2011 01:06 PM

SSH Compression
 
Update:
So far, with only a few clients on the network, I can't tell how much difference there really is, but subjectively it seems much (much!) faster with compression enabled. Apps like Libre Office, when minimized and maximized, feel pretty much like working on the server.
Can anyone else please check this? It seems a worthwhile exercise to me. Why is it not enabled by default?*
On 29 Aug 2011, at 12:10 PM, Jeff wrote:Thanks for the input, David.
Still getting my head around *NX. Can the client work from the thin-clients without loading a windowing system?
In the meantime, I found this article*http://ubuntuforums.org/archive/index.php/t-368869.html about compression.
Looking around the configuration files I don't see any compression enabled in*/var/lib/tftpboot/ltsp/i386/lts.conf so I've added:
## SSH compression between LTSP client and serverNETWORK_COMPRESSION = True*
remotely, but haven't been onsite to test it yet.
/var/lib/tftpboot/ltsp/i386/config-2.6.38-8-generic has several compression parameters, but nothing explicitly about SSH from what I can see.
Will post an update when I've had a chance to test.
Cheers,
Jeff



On 24 Aug 2011, at 3:24 PM, David Groos wrote:Hey Jeff, Sounds like you are looking for good gui remote access over ssh? I use FreeNX as the server and use NoMachine's client and now also use OpenNX since it works well with lion-10.7.* The access over broadband internet is just like sitting at the computer--works great to manage remote servers running Edubuntu/ltsp.* I hear it is even a decent experience over dial-up.* So, while I don't know what the compression is, it must be pretty good to work this well in this situation.* If you have more questions, let me know.
David

On Wed, Aug 24, 2011 at 7:15 AM, Jeff <jeff@wildcoast.com> wrote:
Hi all,
I don't have easy access to a server at the minute, and not sure where the settings are anyway; but I've been wondering about this for a while and am just hoping that someone can point me in the right direction:
A week or so ago when I was onsite at a school, I ran a binary tcpdump to get an indication of network usage with approximately 12 thin clients working.
It wasn't a very precisely measured test or anything, but the server sent/received a Gigabyte of traffic in about a couple of minutes.
So I'm just wondering whether SSH compression is enabled by default or not? And if it is, whether there's any way to tweak it?
Also, it occurs to me that SSH compression would have to be lossless, by nature. So I'm wondering if there's any way to get something like tight-vnc working; or whether we should try a lightweight X desktop like XFCE?
I'm not really happy about the performance, compared to terminal server, for ex, or even the old Fedora/Gnome K12-LTSP we upgraded from.
Insights and pointers appreciated. Flames > /dev/null
;-)
--Jeff Brown
Tel:+27-74-101 5170 Fax:+27-86-532 3508www.wildcoast.co.za


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--Jeff Brown
Tel:+27-74-101 5170Fax:+27-86-532 3508www.wildcoast.co.za

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David Groos 08-30-2011 10:04 PM

SSH Compression
 
Hi Jeff,
I'm thinking I hadn't understood what you were asking for--NX is an application to do remote access, like tight-vnc. *Sounds like you want to compress the video as it gets sent over the network as part of the normal LTSP thin client process. *Yes?
Compression is part and parcel of the LTSP thin client system, I think. *For questions like you are asking, I would recommend that you jump on some irc application like pidgin internet messenger and go to the #ltsp room and ask your question on line. *It is much more active than the #edubuntu room and it seems that most all of my questions seem to be about ltsp :-) *This list server has been kinda thin on answers lately.
Good luck on tracking down some satisfaction.David
On Aug 29, 2011, at 5:10 AM, Jeff wrote:Thanks for the input, David.
Still getting my head around *NX. Can the client work from the thin-clients without loading a windowing system?
In the meantime, I found this article*http://ubuntuforums.org/archive/index.php/t-368869.html about compression.
Looking around the configuration files I don't see any compression enabled in*/var/lib/tftpboot/ltsp/i386/lts.conf so I've added:
## SSH compression between LTSP client and serverNETWORK_COMPRESSION = True*
remotely, but haven't been onsite to test it yet.
/var/lib/tftpboot/ltsp/i386/config-2.6.38-8-generic has several compression parameters, but nothing explicitly about SSH from what I can see.
Will post an update when I've had a chance to test.
Cheers,
Jeff



On 24 Aug 2011, at 3:24 PM, David Groos wrote:Hey Jeff, Sounds like you are looking for good gui remote access over ssh? I use FreeNX as the server and use NoMachine's client and now also use OpenNX since it works well with lion-10.7.* The access over broadband internet is just like sitting at the computer--works great to manage remote servers running Edubuntu/ltsp.* I hear it is even a decent experience over dial-up.* So, while I don't know what the compression is, it must be pretty good to work this well in this situation.* If you have more questions, let me know.
David

On Wed, Aug 24, 2011 at 7:15 AM, Jeff <jeff@wildcoast.com> wrote:
Hi all,
I don't have easy access to a server at the minute, and not sure where the settings are anyway; but I've been wondering about this for a while and am just hoping that someone can point me in the right direction:
A week or so ago when I was onsite at a school, I ran a binary tcpdump to get an indication of network usage with approximately 12 thin clients working.
It wasn't a very precisely measured test or anything, but the server sent/received a Gigabyte of traffic in about a couple of minutes.
So I'm just wondering whether SSH compression is enabled by default or not? And if it is, whether there's any way to tweak it?
Also, it occurs to me that SSH compression would have to be lossless, by nature. So I'm wondering if there's any way to get something like tight-vnc working; or whether we should try a lightweight X desktop like XFCE?
I'm not really happy about the performance, compared to terminal server, for ex, or even the old Fedora/Gnome K12-LTSP we upgraded from.
Insights and pointers appreciated. Flames > /dev/null
;-)
--Jeff Brown
Tel:+27-74-101 5170 Fax:+27-86-532 3508www.wildcoast.co.za



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Jeff 08-31-2011 05:47 AM

SSH Compression
 
Hi David,
Yes I noticed the echo in here. ;-)
Actually I found the answer I was looking for. The parameter*NETWORK_COMPRESSION = True does the trick.*
It's disabled by default according to*http://manpages.ubuntu.com/manpages/lucid/man5/lts.conf.5.html
NETWORK_COMPRESSION boolean, default False

Enables compression of the SSH traffic over the network. Note that
while this will reduce your network traffic, it will increase your
cpu load.

I've yet to test it with more than half a dozen terminals, but from what I can tell so far it is a well worthwhile trade. You should try it. :)
Cheers,
Jeff
P.S. Hey Jonathan, how's Canada? Hope you don't mind but I thought I'd CC you in to solicit your comment if possible.*



On 31 Aug 2011, at 12:04 AM, David Groos wrote:Hi Jeff,
I'm thinking I hadn't understood what you were asking for--NX is an application to do remote access, like tight-vnc. *Sounds like you want to compress the video as it gets sent over the network as part of the normal LTSP thin client process. *Yes?
Compression is part and parcel of the LTSP thin client system, I think. *For questions like you are asking, I would recommend that you jump on some irc application like pidgin internet messenger and go to the #ltsp room and ask your question on line. *It is much more active than the #edubuntu room and it seems that most all of my questions seem to be about ltsp :-) *This list server has been kinda thin on answers lately.
Good luck on tracking down some satisfaction.David
On Aug 29, 2011, at 5:10 AM, Jeff wrote:Thanks for the input, David.
Still getting my head around *NX. Can the client work from the thin-clients without loading a windowing system?
In the meantime, I found this article*http://ubuntuforums.org/archive/index.php/t-368869.html about compression.
Looking around the configuration files I don't see any compression enabled in*/var/lib/tftpboot/ltsp/i386/lts.conf so I've added:
## SSH compression between LTSP client and serverNETWORK_COMPRESSION = True*
remotely, but haven't been onsite to test it yet.
/var/lib/tftpboot/ltsp/i386/config-2.6.38-8-generic has several compression parameters, but nothing explicitly about SSH from what I can see.
Will post an update when I've had a chance to test.
Cheers,
Jeff



On 24 Aug 2011, at 3:24 PM, David Groos wrote:Hey Jeff, Sounds like you are looking for good gui remote access over ssh? I use FreeNX as the server and use NoMachine's client and now also use OpenNX since it works well with lion-10.7.* The access over broadband internet is just like sitting at the computer--works great to manage remote servers running Edubuntu/ltsp.* I hear it is even a decent experience over dial-up.* So, while I don't know what the compression is, it must be pretty good to work this well in this situation.* If you have more questions, let me know.
David

On Wed, Aug 24, 2011 at 7:15 AM, Jeff <jeff@wildcoast.com> wrote:
Hi all,
I don't have easy access to a server at the minute, and not sure where the settings are anyway; but I've been wondering about this for a while and am just hoping that someone can point me in the right direction:
A week or so ago when I was onsite at a school, I ran a binary tcpdump to get an indication of network usage with approximately 12 thin clients working.
It wasn't a very precisely measured test or anything, but the server sent/received a Gigabyte of traffic in about a couple of minutes.
So I'm just wondering whether SSH compression is enabled by default or not? And if it is, whether there's any way to tweak it?
Also, it occurs to me that SSH compression would have to be lossless, by nature. So I'm wondering if there's any way to get something like tight-vnc working; or whether we should try a lightweight X desktop like XFCE?
I'm not really happy about the performance, compared to terminal server, for ex, or even the old Fedora/Gnome K12-LTSP we upgraded from.
Insights and pointers appreciated. Flames > /dev/null
;-)
--Jeff Brown
Tel:+27-74-101 5170 Fax:+27-86-532 3508www.wildcoast.co.za




--Jeff Brown
Tel:+27-74-101 5170Fax:+27-86-532 3508www.wildcoast.co.za

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Neal McBurnett 08-31-2011 04:15 PM

SSH Compression
 
They don't mention it there, but I think adding compression might also
increase latency. That would be a bad thing for those who mainly use
ssh for interactive access to the command line using terminal
emulators - you often see a round trip for every character, and
clearly that can't be compressed very much.

As others have mentioned, there are probably other protocols that are
better and more convenient for doing remote GUIs, with more effective
compression built in.

Neal McBurnett http://neal.mcburnett.org/

On Wed, Aug 31, 2011 at 07:47:43AM +0200, Jeff wrote:
> Hi David,
>
> Yes I noticed the echo in here. ;-)
>
> Actually I found the answer I was looking for. The
> parameter NETWORK_COMPRESSION = True does the trick.
>
> It's disabled by default according to http://manpages.ubuntu.com/manpages/lucid
> /man5/lts.conf.5.html
>
> NETWORK_COMPRESSION
>
> boolean, default False
>
> Enables compression of the SSH traffic over the network. Note that
> while this will reduce your network traffic, it will increase your
> cpu load.
>
>
>
> I've yet to test it with more than half a dozen terminals, but from what I can
> tell so far it is a well worthwhile trade. You should try it. :)
>
> Cheers,
>
> Jeff
>
> P.S. Hey Jonathan, how's Canada? Hope you don't mind but I thought I'd CC you
> in to solicit your comment if possible.
>
>
>
>
> On 31 Aug 2011, at 12:04 AM, David Groos wrote:
>
>
> Hi Jeff,
>
> I'm thinking I hadn't understood what you were asking for--NX is an
> application to do remote access, like tight-vnc. Sounds like you want to
> compress the video as it gets sent over the network as part of the normal
> LTSP thin client process. Yes?
>
> Compression is part and parcel of the LTSP thin client system, I think.
> For questions like you are asking, I would recommend that you jump on some
> irc application like pidgin internet messenger and go to the #ltsp room and
> ask your question on line. It is much more active than the #edubuntu room
> and it seems that most all of my questions seem to be about ltsp :-) This
> list server has been kinda thin on answers lately.
>
> Good luck on tracking down some satisfaction.
> David
>
> On Aug 29, 2011, at 5:10 AM, Jeff wrote:
>
>
> Thanks for the input, David.
>
> Still getting my head around *NX. Can the client work from the
> thin-clients without loading a windowing system?
>
> In the meantime, I found this article http://ubuntuforums.org/archive/
> index.php/t-368869.html about compression.
>
> Looking around the configuration files I don't see any compression
> enabled in /var/lib/tftpboot/ltsp/i386/lts.conf so I've added:
>
> ## SSH compression between LTSP client and server
> NETWORK_COMPRESSION = True
>
> remotely, but haven't been onsite to test it yet.
>
> /var/lib/tftpboot/ltsp/i386/config-2.6.38-8-generic has several
> compression parameters, but nothing explicitly about SSH from what I
> can see.
>
> Will post an update when I've had a chance to test.
>
> Cheers,
>
> Jeff
>
>
>
>
> On 24 Aug 2011, at 3:24 PM, David Groos wrote:
>
>
> Hey Jeff, Sounds like you are looking for good gui remote access
> over ssh? I use FreeNX as the server and use NoMachine's client and
> now also use OpenNX since it works well with lion-10.7. The access
> over broadband internet is just like sitting at the computer--works
> great to manage remote servers running Edubuntu/ltsp. I hear it is
> even a decent experience over dial-up. So, while I don't know what
> the compression is, it must be pretty good to work this well in
> this situation. If you have more questions, let me know.
> David
>
> On Wed, Aug 24, 2011 at 7:15 AM, Jeff <jeff@wildcoast.com> wrote:
>
> Hi all,
>
> I don't have easy access to a server at the minute, and not
> sure where the settings are anyway; but I've been wondering
> about this for a while and am just hoping that someone can
> point me in the right direction:
>
> A week or so ago when I was onsite at a school, I ran a binary
> tcpdump to get an indication of network usage with
> approximately 12 thin clients working.
>
> It wasn't a very precisely measured test or anything, but the
> server sent/received a Gigabyte of traffic in about a couple of
> minutes.
>
> So I'm just wondering whether SSH compression is enabled by
> default or not? And if it is, whether there's any way to tweak
> it?
>
> Also, it occurs to me that SSH compression would have to be
> lossless, by nature. So I'm wondering if there's any way to get
> something like tight-vnc working; or whether we should try a
> lightweight X desktop like XFCE?
>
> I'm not really happy about the performance, compared to
> terminal server, for ex, or even the old Fedora/Gnome K12-LTSP
> we upgraded from.
>
> Insights and pointers appreciated. Flames > /dev/null
>
> ;-)
>
> --
> Jeff Brown
>
> Tel:+27-74-101 5170
> Fax:+27-86-532 3508
> www.wildcoast.co.za
>
>
>
>
>
>
>
>
> --
> Jeff Brown
>
> Tel:+27-74-101 5170
> Fax:+27-86-532 3508
> www.wildcoast.co.za
>
>
>

> --
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> ubuntu-education@lists.ubuntu.com
> Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-education


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