Re: tc + squid

Robert Dale wrote:
>
> Oops.. I delete the original email..
>
> Anyway, basically what I was wondering with tc and squid
> is can they survive together harmoniously? I haven't had the
> time to investigate it first-hand, but according to linx kernel
> docs, you're never supposed to use "IP: always defrag" with a normal
> router. I'm wondering how that would affect tc stuff or even just
> router stuff in general. I'll probably find out this weekend..
> Just curious if anyone had squid running on their router at the moment
> so I can avoid any pitfalls and keep my hair ;)
>
> Some details..
>
> The router is the most important part. It does QoS - several clients
> with different subscriptions to different types of QoS and bandwidth
> (also controlled in linux). It would be nice to run squid on it also
> to save bandwidth.

Well, actually I use both on my gateway and have some configuration
problems.
The setup I want to put in place is :

1) - transparent proxying on 80 redirecting on
2) - squid, 3128
3) - squid has it's own delay pools
4) - QoS on the server, except for what comes from squid (it is not
desirable to do bandwith management on what comes from the cache, as
what I want to regulate is the stuff coming from the other side of the
router), that's why squid uses also delay pools, and should not be
limited by QoS (QoS code, AFAIK, can not know whether data was fetched
from the source or from the cache).

Actually, I did not manage do make 4) work because of lack of time to
properly configure it. QoS is not an easy thing and linux docs about it
are scarce. But I'll beat it soon.

I am also "always defragment"ing on the server, I do masquerading and
transparent proxying so I have to.

The QoS code involves only sending data on the wire. Assuming that it
handles packets just before sending them, I suppose that "always
defrag" (as it saves some IP headers) will increase a bit performance,
especially in bandwith constrained environments. If your router is the
only gateway to the outside, and if you have only ethernet inside (no
need to refrag), I suppose be you can do this, but you break RFC 1812.

If you want to check different QoS scenarii, you can grab the Network
Simulator developped at berkeley (http://www-mash.cs.berkeley.edu/ns/)
and the Sally Floyd papers at http://www-nrg.ee.lbl.gov/floyd/.

Hope it helps.

-- 
Michel Blanc <mblanc@erasme.org>
Centre Erasme
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