Re: [LARTC] TC-ng questions/problems

["lartc@manchotnetworks.net" <lartc@manchotnetworks.net>]

Hi Joost,

I think that maybe you have run across an issue that I too had trouble
with. A snip from a message from Martin BROWN explains:

> You have not actually found a bug, but rather a historical strangeness
> about the Linux traffic control system.  For reasons of which I'm
> ignorant, the syntax for the "tc" command uses bps for bytes/second. 
So,
> 64000 bytes/second is actually 512 kilobits/second ("512 kbps" in
common
> usage), but is 512 kbit to the "tc" tool.  Here's a brief chart:
> 
>                       tc syntax       tcng syntax
>                   +----------------+----------------+
>      bytes/second |      bps       |      Bps       |
>       bits/second |      bit       |      bps       |
>  kilobytes/second |     kbps       |     kBps       |
>   kilobits/second |     kbit       |     kbps       |
>                   +----------------+----------------+
> 
> Note that the tcng syntax is exactly the same sort of syntax we use in
> general when discussing speed of WAN links.  "It's a 512 kbps line"
means
> it's 512 kilobits per second, but this would be 64000 bytes per second
if
> we were writing a "tc" command line.


Hope this helps!

Cheers

Chalres

On Thu, 2004-08-05 at 09:53, Joost Kraaijeveld wrote:
> Hi all,
> 
> We have 2 class C networks that are connected by a Linux router with the internet. We want to apply traffic control (bandwidth control). For that we wrote the tcc script below. We have 2 problems:
> 
> 1. To establish a 2 megagit download we must actually set the value to 2500kbps. Is there a possible reason for that?
> 2. If we enable the WAN device we get very hight ping times (they change from 21.1 ms to > 2000 ms) and erratic upload values that partly suffer from the problem above (we want to allow for an upload of 512kb and have to specify a upload of 712 to get that) but most of the time we have a far worse actual upload. Anyone any ideas? 
> 
> We use Debian 2.6.3-1-386 (Sarge) with tcng 9m.
> 
> Any help is greatly appreciated.
> 
> Groeten,
> 
> Joost Kraaijeveld
> Askesis B.V.
> Molukkenstraat 14
> 6524NB Nijmegen
> tel: 024-3888063 / 06-51855277
> fax: 024-3608416
> e-mail: J.Kraaijeveld@Askesis.nl
> web: www.askesis.nl
> 
> ///////////////////////////////////////////////////////////////////////////
> #include "fields.tc"
> #include "ports.tc"
> 
> #define WAN     eth0
> #define LAN83   eth1
> #define LAN84   eth2
> 
> /* The WAN section is about upload to the internet */
> 
> dev WAN
> {
>   egress
>   {
>     class ( <$uploadRouter> )       if ip_src = 192.168.83.1 || ip_src = 192.168.84.1;
>     class ( <$uploadGKS>  )         if ip_src = 192.168.83.22 ;
>     class ( <$upload83>   )         if ip_src:24 = 192.168.83.0 ;
>     class ( <$upload84>   )         if ip_src:24 = 192.168.84.0 ;
>     class ( <$others> )             if 1 ;
> 
>     htb ()
>     {
>       class ( rate 18Mbps, ceil 18Mbps )
>       {
>         $uploadRouter = class ( rate  18Mbps,   ceil 18Mbps );
>         $uploadGKS    = class ( rate  10Mbps,   ceil 10Mbps ) ;
>         $upload83     = class ( rate  5Mbps,    ceil 5Mbps ) ;
>         $upload84     = class ( rate  712kbps,  ceil 712kbps ) ;
>         $others       = class ( rate  18Mbps ,  ceil 18Mbps ) ;
>       }
>     }
>   }
> }
> 
> /* This section is about downloading to the 83 network */
> 
> dev LAN83
> {
>   egress
>   {
>     class ( <$downloadRouter> )     if ip_dst = 192.168.83.1;
>     class ( <$downloadGKS> )        if ip_dst = 192.168.83.22;
>     class ( <$download> )           if ip_dst:24 = 192.168.83.0;
>     class ( <$others> )             if 1 ;
> 
>     htb ()
>     {
>       class ( rate 18Mbps, ceil 18Mbps )
>       {
>         $downloadRouter = class ( rate  18Mbps, ceil 18Mbps ) ;
>         $downloadGKS    = class ( rate  10Mbps, ceil 10Mbps ) ;
>         $download       = class ( rate  5Mbps,  ceil 5Mbps ) ;
>         $others         = class ( rate  18Mbps, ceil 18Mbps ) ;
>       }
>     }
>   }
> }
> 
> /* This section is about downloading to the 84 network */
> 
> dev LAN84
> {
>   egress
>   {
>         class ( <$download> )   if ip_dst:24 = 192.168.84.0;
>         class ( <$others> )             if 1 ;
>     htb ()
>     {
>       class ( rate 18Mbps, ceil 18Mbps )
>       {
>         $download  = class ( rate  2500kbps,ceil 2500kbps ) ;
>         $others    = class ( rate  18Mbps,      ceil 18Mbps ) ;
>       }
>     }
>   }
> }
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