[LARTC] Simply IMQ

Tue, 06 Jul 2004 15:23:21 -0300

Walt, www.linuximq.net version is the evolution from Devik->McHardy's 
IMQ. Roy started a project where he developed his own implementation of 
IMQ like functionality. I can't tell you more about his version because 
I never had a chance to give it a try.

The IMQ version from www.linuximq.net that comes from the original IMQ 
implementation really needs patching the kernel and iptables sources.

Andre

Walt Wyndroski wrote:
> So you are saying that I do not need to patch my kernel? I do not understand
> that statement. I had to recompile my kernel with the imq patch as well as
> iptables before IMQ would work for me. The way I have always understood IMQ
> is that it is a virtual network device, a virtual network card if you will.
> Therefore it seems to me that egress would apply since iptables is only
> being used to redirect traffic through the virtual IMQ device. IPROUTE2/TC
> would then shape traffic leaving the virutal IMQ device (egress traffic).
> This is how I understand IMQ. If I am wrong, please set me straight.
> 
>>From what you are saying, either IMQ is completely unstable or iptables
> and/or the tcp/ip stack is unstable. Not that I am a guru on the internals
> of iptables or the Linux tcp/ip stack, but I think iptables and the Linux
> tcp/ip stack is most likely stable. To be fair, I must admit that I have not
> had a full opportunity to test out your version of IMQ either, only the
> prior versions.
> 
> Who's version of IMQ resides on www.linuximq.org ?
> 
> Walt Wyndroski
> 
> 
> ----- Original Message ----- 
> From: "Roy" <roy@xxx.lt>
> To: "Walt Wyndroski" <wdwrn@friendlycity.net>; <lartc@mailman.ds9a.nl>
> Sent: Tuesday, July 06, 2004 10:34 AM
> Subject: Re: [LARTC] Simply IMQ
> 
> 
> 
>>Probably I was the last one who changed imq code.
>>so here is are the facts:
>>Basicaly all imq versions are usefull under aproriate condition, whis is
> 
> do
> 
>>not touch localy generated traffic.
>>ingress nad egress terms are not correct for imq, because it is iptables
>>module, not nic.
>>Just my version hooks on different iptables hooks, and simply ignores all
>>local generated traffic. It cant be crashed with incorrect rules.
>>basicaly only advantage of my version is nore clean way to hook on
> 
> iptables,
> 
>>code is same for 2.4 and 2.6 kernels, and no need to patch, stability
> 
> should
> 
>>be same on both kernels.
>>Now it is hard to say why imq crash, because crashes occur in various
> 
> places
> 
>>not related to this module, it seems like memory leak, but does not like
> 
> imq
> 
>>can have such bug. I suppose there is somethisng wrong with iptables or
> 
> tcp
> 
>>code itself, since imq does big mess with packets by droping and
> 
> reordering
> 
>>then alot.
>>
>>Anyway imq does not work as I expected, basicaly all forward shaping is
>>quite hard, I was trying to make tcp traffic predictor because else it is
>>too late.
>>It must be sart enough to work I need to adjust predictor delay, and
> 
> packets
> 
>>size. what makes it quite hard to implement.
>>
>>
>>
>>----- Original Message ----- 
>>From: "Walt Wyndroski" <wdwrn@friendlycity.net>
>>To: <lartc@mailman.ds9a.nl>
>>Sent: Tuesday, July 06, 2004 4:48 PM
>>Subject: [LARTC] Simply IMQ
>>
>>
>>
>>>I've followed this list for quite a long time and have even
>>>posted a couple
>>>of times. I used the early versions of IMQ from Devik (I think that was
>>
>>his
>>
>>>name), and it worked well. I only ever got the chance to implement it in
>>
>>my
>>
>>>test environment. I now need to implement it in my production
> 
> environment.
> 
>>>My Linux core router has nine interfaces and has a 27 megabit connection
>>
>>to
>>
>>>the internet. It is quite busy much of the time. It runs Fedora Core 1
> 
> now
> 
>>>but will most likely be upgraded to Fedora Core 2 in the next month or
> 
> so.
> 
>>>Now with all that said, here is my question. I see that maintenance of
> 
> IMQ
> 
>>>has been passed on a couple of times. I see some people say that IMQ is
>>
>>not
>>
>>>stable and should not be put into a production environment. My use of
> 
> IMQ
> 
>>a
>>
>>>year ago invovled only egress qdiscs using HTB and SFQ because the
> 
> egress
> 
>>>qdiscs were much more powerful and better than the ingress qdisc. The
> 
> only
> 
>>>problem that I ever had with IMQ was using the iptables target with both
>>>PREROUTING and POSTROUTING. I see Roy has posted that IMQ essentially
>>>crashes when doing egress shaping. Is this correct? I've always
> 
> understood
> 
>>>egress as outbound shaping/filtering and ingress as inbound
>>>shaping/filtering. I say that because I saw in an earlier post by Roy
> 
> that
> 
>>>he changed his terminology to INPUT,OUTPUT, and FORWARD. Was he not
> 
> using
> 
>>>the terms egress and ingress correctly? I see that the current 'big'
>>
>>problem
>>
>>>is touching locally generated traffic. What I need to know is which
>>
>>version
>>
>>>of IMQ is most stable for kernel 2.6? Or even kernel2.4? Is it Devera's?
>>>McHardy's? Correa's? or Roy's? Or should I just leave it alone? My
>>
>>apologies
>>
>>>if I got names wrong.
>>>
>>>This is probably a long email just to ask that question, but I can't
> 
> seem
> 
>>to
>>
>>>find an answer from the list archives. I downloaded the whole 46 mb
>>
>>archive
>>
>>>and essentially read 90% of the posts related to IMQ. I'm just trying to
>>
>>get
>>
>>>a good understanding of what's happening with/to IMQ.
>>>
>>>Thank you in advance for any advice.
>>>
>>>Walt Wyndroski
>>>
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>>>
>>
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> 
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