Enable netem in my Linux box

Enable netem in my Linux box

[Koon Wah Yick]

Hi:

My Linux box has CentOS5 installed.  But I could not run tc command with any
netem parameters in command line. as shown in web site
http://linux-net.osdl.org/index.php/Netem.  I suspect, Netem was either not part
of the installed OS or has not been enabled.  Can you tell how to verified?
When I type in "rpm -qa" I see only iproute-2.6.18-4.el5, do I need iproute2?
Can you tell me how to update my Linux kernel to include netem functionality.
Thanks,

Koon-Wah.

Re: Enable netem in my Linux box

[Stephen Hemminger]

On Wed, 09 May 2007 11:31:17 -0400
Koon Wah Yick <kyick@alcatel-lucent.com> wrote:

> Hi:
> 
> My Linux box has CentOS5 installed.  But I could not run tc command with any
> netem parameters in command line. as shown in web site
> http://linux-net.osdl.org/index.php/Netem.  I suspect, Netem was either not part
> of the installed OS or has not been enabled.  Can you tell how to verified?
> When I type in "rpm -qa" I see only iproute-2.6.18-4.el5, do I need iproute2?
> Can you tell me how to update my Linux kernel to include netem functionality.
> Thanks,
> 
> Koon-Wah.
> 
> 
> -
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

modinfo sch_netem

-- 
Stephen Hemminger <shemminger@linux-foundation.org>

Re: Enable netem in my Linux box

[Koon Wah Yick]

Stephen:

Thank you for your response, I type in modinfo sch_netem

Here is what I got:

filename: /lib/modules/2.6.11-1.1369_FC4/kernel/net/sched/sch_netem.ko
license: GPL
vermagic: 2.6.11-1.l369_FC 686 REGPARM 4KSTACKS gcc-4.0
depends:
srcversion: BD4563861423428FF0D5918

when I try the following "tc" command with netem

> tc qdisc change dev eth0 root netem loss 0.1%

I got the error message
RTNETLINK answers: No such file or directory.

I downloaded the ipRoute2 packet, build and re-install.  Nothing change, same
problem.  I do "make xconfig" on my current kernel, see component netem is not
enable.  I enable it and re-build the kernel that does not work for me as well,
the new kenerl does not boot (there may be other problem in building it).  Is
there an easier way to enable NETEM?

Koon-Wah.


On 5/10/2007 11:42 AM, Stephen Hemminger wrote:
> On Wed, 09 May 2007 11:31:17 -0400
> Koon Wah Yick <kyick@alcatel-lucent.com> wrote:
> 
> 
>>Hi:
>>
>>My Linux box has CentOS5 installed.  But I could not run tc command with any
>>netem parameters in command line. as shown in web site
>>http://linux-net.osdl.org/index.php/Netem.  I suspect, Netem was either not part
>>of the installed OS or has not been enabled.  Can you tell how to verified?
>>When I type in "rpm -qa" I see only iproute-2.6.18-4.el5, do I need iproute2?
>>Can you tell me how to update my Linux kernel to include netem functionality.
>>Thanks,
>>
>>Koon-Wah.
>>
>>
>>-
>>To unsubscribe from this list: send the line "unsubscribe netdev" in
>>the body of a message to majordomo@vger.kernel.org
>>More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 
> modinfo sch_netem
> 

Re: Enable netem in my Linux box

[Stephen Hemminger]

On Thu, 10 May 2007 12:09:46 -0400
Koon Wah Yick <kyick@alcatel-lucent.com> wrote:

> Stephen:
> 
> Thank you for your response, I type in modinfo sch_netem
> 
> Here is what I got:
> 
> filename: /lib/modules/2.6.11-1.1369_FC4/kernel/net/sched/sch_netem.ko
> license: GPL
> vermagic: 2.6.11-1.l369_FC 686 REGPARM 4KSTACKS gcc-4.0
> depends:
> srcversion: BD4563861423428FF0D5918
> 
> when I try the following "tc" command with netem
> 
> > tc qdisc change dev eth0 root netem loss 0.1%
> 
> I got the error message
> RTNETLINK answers: No such file or directory.
> 

You want to use 'add' not 'change'.
The examples on the linux-net page are sequential, so the first one uses 'add'.
Later examples, then use change to alter parameters

Re: Enable netem in my Linux box

[Koon Wah Yick]

Stephen:

Thank you, I got it.  I try the same command again with "add" and "change" they
all work.(no error)  But when I start my Network Emulator, how can I stop it.
Do I have to delete any file I create when doing "add"?  If yes, where is it?

Koon-Wah.

On 5/10/2007 12:57 PM, Stephen Hemminger wrote:
> On Thu, 10 May 2007 12:09:46 -0400
> Koon Wah Yick <kyick@alcatel-lucent.com> wrote:
> 
> 
>>Stephen:
>>
>>Thank you for your response, I type in modinfo sch_netem
>>
>>Here is what I got:
>>
>>filename: /lib/modules/2.6.11-1.1369_FC4/kernel/net/sched/sch_netem.ko
>>license: GPL
>>vermagic: 2.6.11-1.l369_FC 686 REGPARM 4KSTACKS gcc-4.0
>>depends:
>>srcversion: BD4563861423428FF0D5918
>>
>>when I try the following "tc" command with netem
>>
>>
>>>tc qdisc change dev eth0 root netem loss 0.1%
>>
>>I got the error message
>>RTNETLINK answers: No such file or directory.
>>
> 
> 
> You want to use 'add' not 'change'.
> The examples on the linux-net page are sequential, so the first one uses 'add'.
> Later examples, then use change to alter parameters

Re: Enable netem in my Linux box

[Stephen Hemminger]

On Thu, 10 May 2007 14:00:40 -0400
Koon Wah Yick <kyick@alcatel-lucent.com> wrote:

> Stephen:
> 
> Thank you, I got it.  I try the same command again with "add" and "change" they
> all work.(no error)  But when I start my Network Emulator, how can I stop it.
> Do I have to delete any file I create when doing "add"?  If yes, where is it?

You probably just want to do: 
tc qdisc del dev eth0 root

That restores the default qdisc (prio-fast)

-- 
Stephen Hemminger <shemminger@linux-foundation.org>

Re: Enable netem in my Linux box

[Koon Wah Yick]

Stephen:

Thank you.  I am happy that when I issue the tc command to drop packets, I do
see the effect.  Is there a command I can use to show all packet count?  packet
send, packet received and packet drop etc...  I don't seems to be able to see
them by command "ifconfig".

Koon-Wah.

On 5/10/2007 2:23 PM, Stephen Hemminger wrote:
> On Thu, 10 May 2007 14:00:40 -0400
> Koon Wah Yick <kyick@alcatel-lucent.com> wrote:
> 
> 
>>Stephen:
>>
>>Thank you, I got it.  I try the same command again with "add" and "change" they
>>all work.(no error)  But when I start my Network Emulator, how can I stop it.
>>Do I have to delete any file I create when doing "add"?  If yes, where is it?
> 
> 
> You probably just want to do: 
> tc qdisc del dev eth0 root
> 
> That restores the default qdisc (prio-fast)
>