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How Much Bandwidth Does VNC Require? 88

Posted by timothy from the as-much-as-you-have dept.
jhartnagle asks: "For VNC (Virtual Network Computing) we are trying to determine what the minimal bandwith would be on a network and still have a functional experience for the user (no or very little lag/latency). Information on any type of network connection would be useful, 10/100Mbps, cable/DSL, and modems. What are some of the setup parameters for the machine that would be the VNC server, x number of bits for color for example. Are there any white papers about VNC, bandwidth requirements and usability? Also, is there similar information about telnet? How low of baud rate can you go before it stops being functional? We would be interested in any academic and practical information. Thanks!" So does anyone have any rules of thumb or words of caution in allocating enough bandwidth here? Better yet, are there any good hints in accomplishing VNC over relatively low bandwidth networks?
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How Much Bandwidth Does VNC Require? More

How Much Bandwidth Does VNC Require?

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  • Some tips for VNC. (Score:1)

    by Anonymous Coward
    Most of this stuff is mentioned in the getting started section at the VNC page.
    If you're going to be doing this over a WAN, use SSH to tunnel. Again the VNC page has some good directions on how to do this. The benifits to using VNC through SSH are three fold. First you know that eveything is reasonably secure, and another benifit, is that with SSH you can use data comprestion. As far as I know you can't do this with standard VNC. I use the highest level of compresion I can before my connection starts to get wacky. Also another big beifit is, when the 1337 kiddies try to do a port scan on your server, VNC won't show up as an listing port. The VNC page also has a list of some good windows SSH clients and servers. Also keep your resolution low ie, 800X600, and 8bit depth. This should save on some more bandwith. Another thing I have noticed (on my LAN), the cpu on the server machine makes a ton of diffence. On my switched lan at home, I have a p200MHZ box running a Redhat 7.0, and when I VNC into it from 1 hop, the session totaly lags... Now if I'm at work on our butt slow lan, and I VNC into another RH 7.0 box about 7 hops away, I get a really decent session. The work server had a pIII 850 in it. These are just a few things to consider. Also, if your trying to do this on win2K, or NT, I would go with PC anywhere, or the termial service in NT Server, and Win2k Server. They both IMHO run a little better than VNC on that platform.

  • One data point (Score:3)

    by Anonymous Coward on Wednesday July 11, 2001 @10:29AM (#91430)

    For a while I tried using a VNC server on Windows with an X-based VNC viewer on Linux. This is on a 10Mb/s ethernet network: the server and client were about five hops away.

    It was so slow as to be unuseable. Response latencies, repaint times and things not repainting when they should were constant problems. All and all it might be useful to do something quick, in an emergancy, but I never want to be subjected to it again. I'll stick with X thank-you-very-much

  • I use VNC to do remote administration of Windows 2000 servers (don't ask, I prefer using SSH with our *BSD and Debian boxes) over a 14.4K connection on a Kyocera Smartphone (Palm based cell phone) and I find it very usable for starting and stopping services, dealing with Active Directory and our backup tape libarary software. On a full screen redraw I might have to wait a few seconds, but it's rather usable. Oh yeah, our servers sit on a 1.5 Mbps link to the Internet.

    Would I use it for word-processing over that 14.4K link? No way. But then I don't need to do that.

    Please tell us a little more about what programs you are planning to run via VNC and I'm sure someone else here has already tried and will relay their experience.
  • That's exactly what I do. I connect from my Palm-powered Kyocera Smartphone to a single Win2K machine and use the Computer Management tool for the rest. But I need VNC to connect from that Palm to the Win2K when I am not in the building and am far away from a laptop or other suitable machine.
  • I set up the following in a config file for ssh:



    Host vnc1
    HostName machine.com
    Compression yes
    CompressionLevel 9
    LocalFoward 5900 vncmachine 5900


    This way I have machine.com accessable to the internet (through a firewall) for ssh, and have it forward the vnc ports to the nt machine (not accessable from the internet).


    All I did for the nt machine was install winvnc, set up the password.

  • I connect to our win2k server over an adsl link, which is 128k going out. It is fine. Yes, it is a little slow, but better than having to drive over to the other office just to create a user id, or change permissions on a file. I even do it over an encrypted ssh tunnel.

  • Netscape was unusable with lbxproxy the last time I tried (client: RH6.1, server: solaris 2.5.1), which was about a year ago. For me, VNC has been much faster, although it is still not enough for me. I need to look into this Tight VNC thingie, as any thing that makes work-from-home easier is a good thing.

  • Re:One data point (Score:3)

    by tzanger ( 1575 ) on Thursday July 12, 2001 @07:25AM (#91436) Homepage

    It was so slow as to be unuseable. Response latencies, repaint times and things not repainting when they should were constant problems. All and all it might be useful to do something quick, in an emergancy, but I never want to be subjected to it again. I'll stick with X thank-you-very-much

    Try turning off "Poll entire screen" in the VNC server. I'm using TightVNC (google search it if you want it) over a DSL link to a VMWare session on a Cel450 located on moderately-loaded T1 and it's responsive enough to almost program over. (1024x768x32) -- if I drop to 8 bit colour it seems to get a little laggier but the screen updates are faster (duh).

    The trick for me was to make sure that "Poll Full Screen" was DISABLED. VNC is totally unusable over a 100mbps switched network if that option is set. I have all the others set (Poll window under cursor, foreground window, console windows and on event received) -- don't worry about the "only" clauses on some of them, that seems to be incorrect.

  • "in a hurry to get second post and forgot the not" Forgot what not? Are you ___ making sense today? (Oops, I forgot the not)
  • Don't forget to take a look at TridiaVNC [tridiavnc.com]. They seem to update the code more often.
    ---
  • MOST COOL! Why hasn't this been modded up to a 4 or 5!?

    I just downloaded and compiled it...works VERY well and is VERY fast...nice.

    Thanks for letting us know!!!!
    ---
  • It depends on many different parameters.

    It might matter what sort of server you're running.

    It probably depends on what size of screen you're sending.

    It definitely depends on what applications you're running.

    It definitely depends on how much you're willing to tollerate lag.

    Anyway, my experience has been with using a Linux client and a Windows NT server with a fairly small screen and a fairly calm application. (By "calm," I mean it's not changing things on the screen a lot.) I found that over ISDN, it was just too slow to be worth bothering with. Over a cable modem, it is perfectly usable. Hence, 128Kbps is not enough, but for my use, 1Mbps is adequate, though I still notice lags.

  • vnc security (Score:3)

    by complex ( 18458 ) <complex@nOsPAM.split.org> on Wednesday July 11, 2001 @09:02PM (#91441) Homepage
    it may be a bit off-topic, but it's worth mentioning, esp. since the poster included cable modems/dsl in his question.

    please please please use the AuthHosts [att.com] setting if you have VNC installed on a publically accessible ip. it limits access by ip, ranges and wildcards are acceptable.

    considering the relatively weak default password sceme in vnc (including no delay in missed password attempts and no default attempt logging), it's a good first step in securing access.

    complex
  • While I agree that 9600 baud is fine for a connection to a bbs or for telnet. The protocol that telnet uses relies heavily on round trip time rather than the speed of the line for it's speed. Telnet is also IP based and has a much lower network utilization than many other applications. At time telnet can feel pretty tight at 56k because of these conditions. It's still a good protocol though. The real question being how well connected the host is by hops rather than how well by bandwidth, but bandwidth can exacerbate the problem. Telnet IS much more comfy on cable. Bare in mind that I recently moved from my 28.8 connection from an appartment at school, to a different state, and a cable connection... and telnet is much happier of here than it was there. Of course, the servers also have much lower load now than they did then, so it's really a circular argument. The point of the argument really was that telnet is a different beast from a BBS on a local dialup.
  • TightVNC code has been folding into TridiaVNC.
  • Well, they can't use TS if they are sitting at anything but another Windows box. (OR maybe a Macintosh, if Mac IE supports ActiveX.) In fact, I haven't been able to install the TSAC (Terminal Services Advanced Client) on a Win98 box. It says I have the wrong version of Windows. I had to load the NT TS 4.0 client, which I haven't been able to find on MS' site. The advantage to VNC is the multiplatform capability. The client can be a PalmPilot, a HP, a Mac. Also, not every application runs well under TS. If someone wanted to check the status of a legacy application, that application might not handle a non-console session well. I know that the Norton AV client gets confused by remote sessions, so there may be other apps that have similar difficulties.
  • OK, can't find information elsewhere and this is _nearly_ on-topic :-)

    I've just been presented with an ancient computer, which I'm thinking of extremely gentle uses for. At the moment it'll probably get used to take printer load off a desktop or two, which it should manage well enough.

    Anyway. Looking at where it's going to be dumped, I'll be happier if it doesn't have to have a monitor, keyboard or anything like that. So, if VNC will run it's rather useful.

    We're currently looking at a P120 running Windows 95 (original) with 16MB and 600MBish free drive space. Oi, no laughing! Yes, it might be getting more RAM and a bigger HDD if we can come up with a strong enough motivation and find some SIMMs... I don't mind turning it down to 640*480 @ 16 colours, I don't care if it'll be slow because I'll hardly ever use it. It would be running over 100Mb ethernet so bandwidth isn't a problem.

    But would it work at all? Honestly, I can't find this sort of information at the moment!

    Thanks,

  • Have a look over here (Score:3)

    by Aphexian ( 29497 ) on Wednesday July 11, 2001 @12:41PM (#91446)
    I was surprised no one had mentioned TightVNC [tightvnc.com], yet.

    It is supposed to be anywhere between 5 and 75% thinner than even plain zlib compression on a VNC stream.

    The original goal appears (to me) to be usability over a dial-up. There are unix as well as win32 variants.

    Hope that helps, good luck!
  • Maybe I'm talking out the wrong end of my anatomy here, but if there is any buffering, there should be a number of race conditions going on. I would guess that the system is better behaved if the bottleneck is closer to the client than the server. If the bottleneck is closer to the server, it is likely to be committed to keep plugging away at something that is already destined for the bit bucket. Offhand, I'd say the phenomenon could be rather startling, something like the initial discovery of thrashing.

  • Check out www.rdesktop.org (Score:3)

    by Raleel ( 30913 ) on Wednesday July 11, 2001 @06:08PM (#91448)
    The rdesktop project implements RDP 4 (aka terminal services) on most unix platforms. I've been using it for the better part of a year as my only windows desktop. It rocks.

    I might also add that I have had no problem whatsoever with norton on terminal services.

    And as for a win98 client, you can make one off your win2k server. Look under your control panel.

  • parameters to greatly increase performance (Score:4)

    by Raleel ( 30913 ) on Wednesday July 11, 2001 @04:27PM (#91449)
    especially over a slow connection...

    ssh -C -L localport:vncmachine:remoteport and tunnel it

    vncviewer -encodings "hextile"

    of course, I have not gotten to try tightvnc.
  • My cable modem is about 100K up and 200K down. I am running a Win 2000 Server under VMware.

    With a Windows VNC client, and a Windows VNC Server at 1152 x 864 @ 32 bits (client forcing 8 bit), I can use VNC for everyday tasks. There is a noticable lag on screen updates, but nothing that can't be lived with.

    Under the same setup, with a Linux VNC server at 1200 x 900 @ 16 bits (not forcing to 8 bits), I get better speeds.

  • I forgot to mention....

    With the Windows Server, I have 'Poll Full Screen' activated.
  • ...try TightVNC. It's a new compression technology added to VNC. It's availble from tightvnc.com [tightvnc.com]. I have found that it is more than usable over a 56k connection even if you are using the java applet in Netscape. The patches are GPLed, just like VNC so there are no unneeded restrictions on using it. Setting your bitrate is a different issue. If you are going to have people accessing via the Java applet, use a 8bit depth. Java can only handle 8bit, and dithering takes forever. If you are going to use the standalone clients (available for all major OSes), then use a depth of 16bit or 24bit. The dithering in the standalong clients is much faster than it is in Java.
    If you need it, I also have a patch for VNC that only allows one session and then kills the server. It will even run a script on exit if desired. Drop me an email if you would like a copy. I would link to a page for it, but I heven't tested it in a high-load production setting yet.
  • PPP is notoriously heavy - that's why many of us (when we were unfortunate enough to have to dial into the net) refused to use PPP, but insisted on ISPs that supported CSLIP instead. It's a little less common, but CSLIP (also known as SLIP with Van Jacobsen (VJ) header compression) is quite a bit more efficient than PPP - do the math for yourself to see the reduced overhead...

    FWIW, I love VNC and use it nearly every day, but if you're trying to remotely control a Windows machine and it's running W2K server or better, I'd stick with the Terminal Services stuff, which is quite a bit faster than any VNC. Also, the VNC clients for some platforms (CE is one notable example) are terrible, while there are pretty good TS clients available (surprise, surprise...)

    FWIW, VNC is very good software, even if it's not the fastest thing out there. I used to work for Tivoli, which sells a really expensive remote control product as part of its management solution. When I showed VNC to the RC team (this was 2-3 years ago), they were amazed, impressed, and recoiled in horror once they realized that there was a completely free solution that worked better than the one we charged megabucks for. (But then that sort of thing was, sadly, true of most all of Tivoli's software...)

    I prefer the Tridia VNC to other VNC "distros", but YMMV, especially if you want Constantin's latest Tight encodings, on which Tridia seems to lag a bit.

  • VNC speed (Score:3)

    by AtariDatacenter ( 31657 ) on Wednesday July 11, 2001 @12:50PM (#91454)
    I can't give you a direct answer, and a lot of it depends on the application you are doing and how its drawing algorithm compares to X. It also depends on what settings you have on your VNC. (And I am assuming we're talking a VNC client on Windows and a VNC server on UNIX.)

    I can say that Netscape on X-Windows over a VPN was DOG SLOW to the point of being near unusuable (Netscape mail, specifically). Switching to VNC over my VPN made things dramatically faster.

    Of course, VNC doesn't quite act the same as a perfect X interface.
  • Very nice. Notice though that Tim Edmonds has been
    posting that he's working on bringing together
    the rdp code with the vnc code to allow you to
    get round the slowness of vnc on windows servers -
    simply take advantage of the rdp server.

    Why? Well, why would you want an rdp client when
    you can manage all of your boxen (not just windows
    or X) - from all of your boxen, with vnc?

    -Baz
  • whoops I should have followed all the threads. The rdp2vnc work is now available, having been completed by James Weatherall:
    http://www.uk.research.att.com/~jnw/downloadable s/
  • There was a paper with benchmark comparisons of Citrix (ICA), WTS (RDP), VNC, and SunRay thin clients at usenix.

    http://www.cs.columbia.edu/~nieh/publications/us en ix2001_slowmotion.pdf

    Summary:
    'Overall, VNC and Sun Ray were faster at higher
    network bandwidths while Citrix and RDP performed
    better at lower network bandwidths.' (this on a web browsing test)
    They also did a streaming video test which basically seemed to show everything except SunRay got processor bound at high bandwidths and that 'visually,
    only Sun Ray achieved good performance even at 100
    Mbps.'

    From your point of view another interesting observation was that VNC sends less data than the others at low bandwidths. ie, the other protocols were still trying to to real time updates, VNC just began to appear sluggish as it waits for client responses. However in the words of the report 'none of the platforms
    provide good response time at 128 Kbps'

    -Baz
  • I would strongly recommend against anything using anything less than ISDN (128kbps) on the client side; I tried running a VNC client over a 28.8kbps modem connection to a server at by school (which I think had 6 T1 lines at the time) and I nearly went insane because of the high latency.

  • I use VNC over my 192k SDSL line to access my PC at work in order to use Bloated Notes from home (yes, supposedly NOTES would work with WINE, but the VPN software doesn't like that), and to access intranet web pages. It's not the most lively interface, but it's ok for light use. (OTOH, I also typically have two telnet connections going at the same time, and I think there's a bit of a bottleneck in the VPN access that reduces the effective bandwidth even more.)

    I use the -bgr233 option to set 8-bit color, it helps a lot though it uglifies things a bit.

    Tom Swiss | the infamous tms | http://www.infamous.net/

  • My question is how did you set this up? What config files are needed to work together for secure VNC, and does ssh work on W2K? THx
  • Yes, I have version 5.0 and its shareware. It runs for 2 hours before you have to shut it down and start it up again. I actually think of this more as a feature.

    It helps me keep track of how long I have been working and gives me an excuse to take a short break every two hours.
  • X-Win32? Blah. The Unix version of the VNC server (it's actually just an X server) works great. X provides a lot more information to VNC than windows, and in an event-driven manner, so that VNC can do minimal updates with good results. The Windows GUI essentially has to be polled, which is why you'll often see WinVNC eating 80-100% CPU on windows while doing even simple things, while on unix it barely makes a dent.

    - - - - -

  • Over ~600kbps it works fine. (Score:4)

    by Doco ( 53938 ) <{moc.ekleo} {ta} {naD}> on Wednesday July 11, 2001 @12:10PM (#91463)
    My situation - my home is hanging off an 802.11 network and I get about 600kbps over that (give or take). My work is connected via T1 and we are about 9 hops away. Ping times around 60-100ms.

    I used VNC all day yesterday with screen resolutions of 1600x1200 @ 32 bits.
    Windoze 98 client, Windoze NT server.

    General performance was "ok". Pulling up a new window had a 1 second or so of lag, and once in a while the rxvt or xemacs screen wouldn't update until I clicked or did some typing in the window. I noticed it most if I was watching while I typed. Then it was ok sometimes, and sometimes I ran into more lag and could be 10-20 characters ahead in my typing from what was being displayed.

    I have tried using TightVNC which works ok - but I 've also had some stability problems with it. It is supposed to work better for low bandwidth applications, but I haven't been able to do a side-by-side type of comparison.
  • Are you using the latest version? I'm not getting the bahaviour you discribe.

  • I would recommend XFree86 4.x for Windows, it has been available for some time now, compiled with Cygwin/Mingw32.

    Works great, and costs nothing, unlike X-Win32, which works great, but costs a lot.
  • >>Also the speed of the connection at the server is more important than at the client end.
    >What on earth does that mean?
    What I meant by this was that the amount of available bandwidth, be it dialup, 1.5mbps, 10mbps, etc. seems to have a greater improvement on the connection, when the increase is at the server side.
    eg (just an example): The conection seems to be much better when you connect from a Dialup Client to a T1 server; than from a client on a T1 line to a server on a dialup line.
    -OctaneZ

    "I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones."

  • VNC usage (Score:5)

    by OctaneZ ( 73357 ) <ben-slashdot2 @ u m a . l i t e c h.org> on Wednesday July 11, 2001 @12:01PM (#91467) Journal
    Note: this is not based on any white papers, but rather years of usage. VNC [att.com] server from experience is much more adept on UNIX servers than on Windows. Remember if you are running Windows you can always change the polling [att.com] to change what part of the screen gets updated (use less bandwidth). Another option to reduce bandwidth (this works on all servers/clients) is reduce the color to 8bit. Also the speed of the connection at the server is more important than at the client end. I have used a client on a Dial-up (29.6 kbps) to connect to windows and unix servers on a T1 line. Remember to keep your software [att.com] up to date, as they make improvements to handling regularly.
    -OctaneZ

    "I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones."
  • ML View [medialogic.it].
    It's a beta, but hey, we're on Slashdot ;-)
    They claim, that it is MUCH better lbx Stuff from X.
    Plz. moderate this up, I think it's a rather useful project, that needs a few good hackers.
    Bye egghat.
  • I actually use a Palm VNC client running over my GSM phone at 9.6.
    The purpose of this is, that I Hotsync over a dialup connection to the Office network.
    Sometimes the Hotsync manager dies during the sync. Then I can use VNC to start the Hotsync Manager again.
    This does require a LOT of patience, but it works (and the nerd in me gets a little kick out of it, each time)!
  • 10Mb/s ethernet, 5 hops away? Hopefully you have that much bandwidth through all 5 hops, or your 10Mbs statement is pretty meaningless.

    I use vnc from my linux box to manage a bunch of NT servers a couple hops away (over a twin T1 setup), and don't find it unuseable. The fact that it's a bunch of NT servers pretty much sucks, but the vnc itself is pretty much bearable, and seems much better than trecking over to the remote provider.

    The one problem is that polling the window on MSWindows seems pretty hard on the CPU. A 3x200 mhz pentium pro on the same 100bT switch is much slower than the 900mhz P3 across the internet.

  • vnc does refuse connections from hosts after about 5 or six attempts. Not that that should stop you from using authhosts or anything. (grin)
  • I can telnet on 56k and still be able to do PINE just fine. What really kills you is the lag time more then the bandwidth. Type in Q and wait .2 seconds to view it is not fun.

    Spoiled brat ;-).. try telnet over a 300bps acoustic coupler SLIP connection. (no, not CSLIP, SLIP) 10 yrs ago.

    But then again, who knows how many /.ers actually remember what KA9Q is and how to use it.

    Speed corrupts. Absolutely.

    Cheers,
    Chris

  • ever hear of ssh
  • We used VNC for several years on our servers, but when the time came to evaluate it for remote desktop control (troubleshoot from home via SSH tunneled VNC), it fell pretty short. We eventually decided to go with Remote Administrator for a couple of reasons: 1. cheap ($700 site license) 2. more efficient than VNC (10-30% utilization on our web servers vs VNC's 30+) 3. easier to setup and configure using the same OpenSSH tunneling setups Radmin has proven to be a very effective "middle-of-the-road" solution between freeware VNC and big-$ remote access solutions.
  • I have used VNC on a LAN and over the internet (DSL <-> Frac. T1 ), I have never tried it over a modem connection. It does jump arround a little, but is very useable. I have found that one of the best ways to improve it's performance is to have a background of one color. Get rid of the fancy wallpaper image, and make it one solid color.
  • The Microsoft 16bit client provided on the WTS CD works marvelously under Wine. The 32 bit, I've never gotten to work, although I haven't tried with newer builds of Wine.
  • I use VNC to admin W2K servers both from on-site and from home. At home, it's 640K DSL over about 9 hops; it's a little sluggish, but I've spent hours doing server configs without running from the room screaming. I've even rebooted from home; comes back up just fine. I've had to turn on "entire-screen polling" in order to get some MS apps to update the screen, but even that doesn't kill the experience. Didn't know about TightVNC until this thread; I'm going to try it tonight!

    I did it once from my in-laws over a modem to show my father-in-law what kind of work we're doing - he was more impressed with VNC than my day job. Oh well...

  • For everybody saying that they use VNC to admin Win2k, I ask WHY? Almost everything you need to do you can do through computer management; if you actually need a remote desktop, use Terminal Services (In Server, Adv Server and Datacenter Server) in Remote Control mode; it's much much faster than VNC will ever be. There's even TSAC which runs in a web page (activeX, admittedly).

  • TightVNC (Score:5)

    by const_k ( 140010 ) on Thursday July 12, 2001 @05:24AM (#91479) Homepage
    Well, TightVNC [tightvnc.com] has been mentioned here already but being the TightVNC developer, I'd like to add a number of points.

    First, to make things clear, TightVNC is a VNC version which mostly concentrates on low bandwidth usage. It can be more than usable on modem connections (starting from 14.4 kbps) but actual bandwidth requirements strongly depend on screen contents and color depth. If you want best performance over a slow link, first of all remove colorful wallpaper from your desktop (and maybe restrict color depth to 8 bits in VNC viewer).

    Next point. Most users know TightVNC for its 1.1 version which may be considered outdated at this moment. TightVNC development has made notable progress since then and bandwidth requirements are decreased a lot. Although new 1.2 release is not ready at this point, but (1) there are preview versions including most 1.2 functionality and (2) I hope it will be released less than in a week counting from now (I only have to do several changes in Win32 version).

    To let you know more what TightVNC is, here is a brief list of features for upcoming release, from new version of its homepage:

    • Local cursor handling. Cursor movements do not generate screen updates any more, remote cursor movements are processed locally by the viewer, so you do not see remote cursor pointer moving too slow behind the local cursor.
    • Efficient compression algorithms. New Tight encoding is optimized for slow and medium-speed connections and thus generates much less traffic as compared to traditional VNC encodings.
    • Configurable compression levels. You can choose any appropriate level of compromise between compression ratios and coding speed, depending on the your connection speed and processor power.
    • Optional JPEG compression. If you don't care too much about perfect image quality, you can enable JPEG coder which would compress color-rich screen areas much more efficiently (and image quality level is configurable too).
    • Operating under Unix and Windows. All new features listed above are available in both Unix and Win32 versions of TightVNC.
    • Web browser access. TightVNC includes Java viewer with support for Tight encoding and local cursor feature (viewer applet may be accessed via built-in HTTP server as in the standard VNC).
    • Automatic SSH tunneling on Unix. Unix version of TightVNC viewer can tunnel connections via SSH automatically using local SSH or OpenSSH client installation.
    • And more. A number of other improvements, performance optimizations and bugfixes, from me and from other people.

    As you can see, most major changes introduced in TightVNC are related to efficient bandwidth usage.

  • Okay, each of our branches had a 64k leased line, and depenfing on what branch a minimum of 3 or maximum of 12 computers on that leased line.

    VNC we found was fine if you connected as 8 bit colour. Connecting through a web brower seemed faster than using the client.

    Although I never used it, others did through RAS (so basically a 33k modem connection) to access other PCs at the head office. They said it was okay there too.
  • Actually, older versions of XWin32 are freeware (or shareware?). I trolled Google and found an old copy. Works great.
  • dont forget that you can actually *encrypt* the Terminal Services session up to 128bit...I have used VNC and have seen no mention of encryption.

    (for you anti-Uncle Bill's(r)) wanna whine and say you cant "share" a session like VNC? TS give the ability to "watch" other sessions or just take them over.

    oh the joys of TS...

    NO SPORK
  • I think both reply's to my post MISSED the point. Sure, you can tunnel *anything* via SSH. That's fine, I use ssh daily. My point was, that VNC by _default_ is insecure, unless you secure it by some other method.

    sheesh. Everything has it's place. If you are too blinded by a lame penguin to see that, then you will never succed in technology.

    NO SPORK
  • why are you using VNC? you can do all these things from another win2k machine using the mmc.p.
  • hmm... i think there's a WinCE Terminal Services client that might do what you want. You'd need to switch devices, though, so that may not be much use to you.
  • No offense, but how old are you? Did you never use telnet (or telnet-like BBS systems) before the web? 9600 is plenty fast for a telnet connection. (Most serial console connections to sun/hpux boxen are static at 9600). If you want low latency, 33.6 is fast enough.
    Your lag in 'pine' is probably based on the server and not the connection.
    But who uses telnet anyway? You should be asking about ssh.
  • Win2k has Terminal Services built in, and as long as you leave it in administrative mode (not application mode), you don't have to pay for it. Heck, if your client is Win2k, then you don't have to pay for it in application mode either.

    It is much faster and more responsive than VNC. I only use VNC for our NT4 and linux boxes.
  • check out for yourself. The bandwidth/latency needed depends very much on what exactly you are doing, and how patient you are. Set it up on a local network with a traffic monitor, and see what kind of bandwidth it uses. If necessary throw it through a traffic shaper and play with it.
  • I can definately back this guy up... I run VNC from my home computer (256k cable modem / win2k) to my school computer (it's a college.. actual bandwidth varies, but on paper it's dual T1 / winME)... it's much more responsive and smoother when the server is on the higher bandwidth, albeit both are very usable, and defiantely beats driving 50 minutes because I forgot to email the newest .cpp file to myself...

    This makes lots of sense because you have to download all of the screen data, but only send mouse data...

    I do have to use 8-bit, however... it is VERY slow when trying to use any higher than that

  • We have 10 remote sites and use VNC to admin well over 100 boxes via 56K frames. The speed is not too bad if you set to 8bit color(even on our 1300 mile frame.) But then VNC will use just about any amount of bandwith the you provide it. I've seen it suck up most of a 100mb connection.
  • >A direct-dialed 2400bps connection to a BBS is >certainly more responsive than telnet over a 56K >PPP link. That's simple math (protocol >overhead), not to mention the empirical >observation of anyone who's tried both. Protocol overhead? BS. It's the routing overhead that gets you. Your 2400 was a direct connection.
  • I read some posts about it, i never saw or used it, but i wonder can i connect to it with non MS clients ?

  • VNC is really terrible connecting to Windows 2000 if you poll the whole screen. On a relatively high-end dual cpu machine I saw the processor queue length jump from three (during a heavy DB2 load) to hover around ten, and the context switches/sec quadruple. If the full screen polling was off, the machine wasn't affected quite as much, but as soon as the mouse was moved, a spike occured. I ran a time test of a load with performance monitor on and VNC poll full screen selected, and it took more than twice the time that a regular load usually does.

    The windows 2000 remote control mode didn't affect the machine at all.

    Most remote control access that I need to do on windows machines requires me to turn on the full screen polling. I would *not* recommend using VNC on a heavily hit production server.
  • Although it is not fast, the speed of connecting to VNC is quite tolerable. One thing I do not like of VNC is its inability to shut off the Java http server, which is a security problem.
  • You need to buy extra licenses from Microsoft to use Terminal Services, which you have to validate directly from them. If you use Terminal Services in Application Server mode, and don't get it approved by Microsoft, it stops working after 90 days.

    What you have to buy is TS-CALs.
    TS-CAL's cost:
    Windows 2000 Terminal Services CAL 5-pack $749
    Windows 2000 Terminal Services CAL 20-pack $2,669

    And if you want to connect over the Internet:
    Windows 2000 Server Internet Connector License $1,999 Unlimited CAL licensing for Internet clients only.
    Windows 2000 Terminal Services Internet Connector License $9,999

    But please, don't believe me, observe these web pages!
    http://www.microsoft.com/windows2000/server/howtob uy/pricing/terminal.asp [microsoft.com]

    http://www.microsoft.com/windows2000/server/howtob uy/pricing/pricingwindows.asp#terminal [microsoft.com]

    Using Terminal Server in remote administration mode does not require extra licenses.
    XFree86 and VNC do not have such licensing requirements.
    I hope this post helps you decide what method of network application use you want to use.


  • Maybe I'm talking out the wrong end of my anatomy here, but if there is any buffering, there should be a number of race conditions going on. I would guess that the system is better behaved if the bottleneck is closer to the client than the server. If the bottleneck is closer to the server, it is likely to be committed to keep plugging away at something that is already destined for the bit bucket.

    TCP doesn't really work this way, since a node will not continue sending packets if earlier ones have not been acknowledged. It's not like the machine just fills the pipe up until it starts backing up and flooding the basement. And even if it were, it's not clear to me how this would have any impact except perhaps at the very tail end of a buffer-pluggingly-large transmission.

  • No offense, but how old are you? Did you never use telnet (or telnet-like BBS systems) before the web? 9600 is plenty fast for a telnet connection.

    What he's saying, and he's quite correct, is that telnet isn't always terribly responsive.

    A direct-dialed 2400bps connection to a BBS is certainly more responsive than telnet over a 56K PPP link. That's simple math (protocol overhead), not to mention the empirical observation of anyone who's tried both.

  • Protocol overhead? BS. It's the routing overhead that gets you. Your 2400 was a direct connection.

    Every character your type in a telnet session gets packaged up in a TCP packet inside an IP packet inside a PPP packet, ballooning it to a dozen or more bytes.

    Every character you type when modemmed directly to a BBS gets sent as exactly one byte (okay, yeah, except for escape sequences).

  • What I meant by this was that the amount of available bandwidth, be it dialup, 1.5mbps, 10mbps, etc. seems to have a greater improvement on the connection, when the increase is at the server side.

    That's what I thought you meant. It doesn't make any sense.

    The observable characteristics of an end-to-end link are latency, bandwidth, and (if not handled by protocol) data loss.

    It is not possible to determine, in band (i.e., leaving aside out-of-band tricks like traceroute and pathchar), at which end these characteristics are being affected.

    So what you say is pretty close to impossible.

    Perhaps what you're observing is the 33Kb ceiling on upstream traffic with 56Kb modems on analog POTS lines.

  • Re:VNC usage (Score:3)

    by raju1kabir ( 251972 ) on Wednesday July 11, 2001 @01:44PM (#91500) Homepage
    Also the speed of the connection at the server is more important than at the client end.

    What on earth does that mean?

  • yeah..member ddial that ran on the apple II, which top speed was 300 baud?!
    now THATS the shit!

    .kb
  • I occasionally VNC into my Linux box from a Windows box elsewhere at home, over 100 Mbps switched Ethernet. It's very slow. Then one time, I vnc'ed into a remote box on a T1. (I have a cable modem.) That was quite fast.

    So I think my point is that it can be processor-intensive, too.
    ________________________________________________

  • That's what I thought you meant. It doesn't make any sense.

    Well, yeah, it does -- maybe. If you take the server being on a dial-up connection and the client being on a T-1 as the example, and the server is doing something over that connection besides just sending VNC images, then that little tiny dialup pipe will have much more impact on the server than if the situation were reversed. Usually, a client will be doing nothing over the connection except VNC, while the server may be doing many other things (including file sharing, web server, etc).

    Perhaps what you're observing is the 33Kb ceiling on upstream traffic with 56Kb modems on analog POTS lines.

    Absolutely, this would have an observable effect. Most connections on a 56K modem are around 46K (downstream, of course). The difference between 46K downstream and 33K upstream (13K) can be pretty significant.

    GreyPoopon
    --

  • Food for thought:

    Latest version of X incorporated a low bandwidth protocol. You run a binary on the remote end called lbxproxy, direct your DISPLAY to it, and then communicate through the lbxproxy. Haven't tinkered with it much, so I can't give much comparison to VNC. (I would imagine Tight VNC would perform better than either LBX or standard VNC. Also not sure if there is a version of Solaris that supports it.)
  • I've used the ARM VNC viewer on an iPAQ PocketPC to view a Win2K box over a 40k/sec HSCSD connection in the UK.

    It was perfectly usable if you can tolerate lag. VNC over a 10Mb/s network is bad enough sometimes, but imagine it over a connection that has to traverse a cell and POTS before it even hits a router of any shape or form.

    But adjust to the lag and it's golden.

    Ryszard
  • I can telnet on 56k and still be able to do PINE just fine. What really kills you is the lag time more then the bandwidth. Type in Q and wait .2 seconds to view it is not fun.
    ----
  • The user also asked about telnet if you actually read everything they wrote. Also, I meant to say "Telnet does not require a fast connection." I was just in a hurry and didn't really preview it beforehand. By the way, I said 56k was just fine and 56k is certainly not a fast connection. Certainly not compared to the T3 I use at work.
    ----
  • Crashes on my computer after 10 minutes and the colors are messed up. Is it me or just my setup?
    ----
  • I would recommend X-Win32. It's a little expensive, over $100 a pop, but works really well over 10 mb/s network. If you're doing it the opposite way around, VNC is probably you're best option. Just keep the servers local and use a network with as much bandwidth as possible.
    ----
  • I haven't seen this mentioned here yet, but i work a help desk in a medium size law firm (~200 win95 machines) and we use vnc to keep our asses planted instead of going to a user's desk to see the latest illegal operation. We have a 100mbit switched network, and vnc doesn't have any noticeable lag. The annoying part is having to force a screen refresh because illegal ops don't show on the remote screen unless you do.
  • but I *like* my pop-up ducky programme.

  • Eh? (Score:3)

    by houTTni ( 463318 ) on Wednesday July 11, 2001 @12:25PM (#91512)
    I'm not sure what is going on with these other guys. I am running a Win2k Server box at home (no flames please) on cable modem (normally 40 up and 300 down) at 800x600 and 32bit and from my work (90mb fiber ring connected to our 10/100 switch) I get great speeds over VNC. I do use the 8bit pixel restrictions to speed it up even more.

    Over the local 10/100 at home there is no lag at all.


    "Press any key to begin."
  • I have to agree. Remote Administrator [famatech.com] is great. It is usable over dial up and near real time when used with 1mbit + connections. Excellent program. I've been using it for a while with very few complains. I prefer it over PC Anywhere.
  • I'm a /. user who used KA9Q. A hint for the rest of you--KA9Q is a HAM Radio Operator's call sign.

  • One thing to remember with SSH tunnels is that the VNC client is likely to decide that the server is local and use RAW encoding, so remember to specify the encoding you want to use.

    Also, your choice of programs is going to matter a lot. I use VNC over an ssh connection from a machine behind a (over-loaded) T1 to connect to a server on DSL. The connection is tunneled over SSH. I have found that FSF Emacs and XTerm are quick, gnome-terminal is tolerable if you are carefull about options, and XChat is unuseable.

    Basicly, any program that draws it's entire windows using MIT-SHM and always copies the entire window even if only one pixel has changed isn't going to work very well. So watch out for programs that have theme-able backgrounds, checkboxes, pop-up ducky calanders, etc.
    (Cough *GNOME* Cough *KDE* Cough)
    These programs aren't going to be usefull. Also, avoid programs that are going to reduce performance to just raw copying large memory blocks. Image Viewers and such like fall into this catagory.

    Use a simple-to-draw window manager and use click-to-focus mode. If you use focus-follows-mouse, then everytime you drag the mouse over a window, the WM is going to resend all the window decorations in the "focus" color.

    There are some CPU/Bandwidth tradeoffs you can make as well. It's worth experimenting a bit to see what works for you. I have a P233 on a 128K (up) DSL connection, and I have found that the spending CPU to reduce bandwidth is almost always the right choice.

    When I am on the LAN (FE), then I can run almost anything without problem. For remote work, I can use emacs and xterm, which is mostly what I use for work anyway.

    Epmos
  • I've been using VNC 3.3.3 for several months now and prefer it very much over pcanywhere. I have used it over a 56K modem line getting actual throughput of 40-43 K. Still works, even if it is slow. I didn't make any kind of tuning changes to it since it seemed to be working ok. Is this the kind of info you want ?

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