Re: [LARTC] using tc to drop packets based on the diffserc or tos

[Michal Soltys <nozo@ziu.info>]

> Hi Michal,
> 
> Can i user filter on the default qdisc attached on the eth0.If then how? 
> (although i read somewhere that there is very little customization that 
> we can do the default qdisc)?

Yes, default qdisc - pfifo_fast - is pretty limited, with 3 bands assigned 
to specific tos values' combinations.

> If i used some classful qdisc than how would i restore my default 
> setting?

Just delete the new qdisc you created, you will go back to pfifo_fast.

> Do we have better way achieving the same?

Well, HFSC or HTB would be a good choice, with SFQ or ESFQ attached to the 
leafs (if i.e. using classes per groups of users).

> Can you suggest me some useful tutorials?

In no particular order (and not necessarily related to your questions):

1) Information about extended tc actions (mirred, ipt, ...) :

iproute2 tarball -> doc/actions

remark: currently it seems, that if you use more than 1 ipt
action in a filter rules, tc will segfault

Also look for info in Russel's docs

2) Excellent Russel's set of docs

http://ace-host.stuart.id.au/russell/files/tc/doc/

remark: contrary to other sources of info (i.e. lartc howto), the u32 docs 
here are superbly accurate and (almost) complete.

minor missing info in u32:
   indev purpose (?)
   mark match (this one is simple, i.e. tc .... u32 match mark 1 flowid X:Y -
     - note that flowid/classid must be last here, or tc will complain).
   dscp can be used instead of tos

3) LARTC howto

http://lartc.org/#download

Pretty old, plenty of info, also plenty of missing info, and some
(like u32) leaving a LOT of important details (almost plain wrong).

4) iproute+tc notes

http://snafu.freedom.org/linux2.2/iproute-notes.html

Also can be found in iproute tarball. Missing info remarks as in 3)

5) Traffic control howto

http://tldp.org/HOWTO/Traffic-Control-HOWTO/index.html

6) Linux policy routing

http://www.policyrouting.org/PolicyRoutingBook/ONLINE/TOC.html

7) ip command reference

http://linux-ip.net/gl/ip-cref/

8) some elementary classification info (BASIC)

http://marc.info/?l=lartc&m\x117569441229800&w=2

9) some discussion with plenty of good info related to HFSC

http://marc.info/?t\x107799591400001&r=1&w=2

10) other HFSC documentation info

http://linux-ip.net/articles/hfsc.en/
http://www.cs.cmu.edu/~istoica/hfsc-tr.ps.gz (good, but detailed and long)
http://www.sonycsl.co.jp/~kjc/software/TIPS.txt (note that *BSD's HFSC
   implementation, is a bit different (no concave curves, 80% limit on
   realtime, ...). Good simple overview, but be careful.

11) marc.info, google, ...
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