On Sat, Dec 08, 2001 at 04:56:04PM -0500, jamal wrote: > > I see that now :-) The right wording appears to be that a Prio is a > > Work-conserving non-policing shaper. > > work conserving is right. non-policing is wrong. Policing is related to > filters. Shaping is related to schedulers. Prio is a scheduler. Ok, so 'work-conserving' encodes the fact that it will never delay packets? > Shaping results in non-work conserving schemes. You can attacha TBF which > shaping inside a Prio qdisc. That would add non-workconserving-ness to it. Ok, but pfifo_fast for example will always be work conserving. > > New wording: > > Do not confuse this classless simple qdisc with the classful PRIO one! > > Although they have a lot in common, the PRIO queue can contain different > > classes, whereas pfifo_fast has hardcoded FIFO bands. > > I am not sure if i like the wording: A class is the result of a > class-ification. Both pfifo_fast and PRIO have builtin class-ifiers. > Essentially if you treated default prio qdisc and pfifo_fast as black > boxes, there is _no_ difference. Dont look at the code, think larger > picture. Well, I aim for the user. For the user, the big picture may be identical but the use is quite different. I don't want to get email 'I tried to add a qdisc to pfifo_fast and it didn't work!'. New wording: Do not confuse this classless simple qdisc with the classful PRIO one! Although they behave similarly, pfifo_fast is classless and you cannot add other qdiscs to it with the tc command. I think this covers what you mean and what I want. > You can have two qdiscs per device, ingress and egress > Please look at the router model i described earlier. The two hooks are > very clearly described there. > Ingress qdisc is work conserving only by design; whereas egress qdiscs > could be non-work conserving. True. The ingress qdisc isn't really dequeued. > Again, look at the definitiions of eg/ingress. You need to have this > diagram drawn: > > http://www.davin.ottawa.on.ca/ols/img9.htm > in your document. It's good, will need to asciify it however. > > other words, it delays certain packets while it doesn't delay others. How > > would you suggest wording this? > > Look at the model draft then lets talk again. Ok. Rewording of the HOWTO will have to wait on a glossary/definition section anyhow. > > > the lo device); they might find that all their packets greater than 2K > > > being dropped. > > > > Sure? > > 100% sure. Try a little experiment then look at the code again. I will, but I bet you 5 euros that I'm right :-) We are talking about the TBF, aren't we? Regards, bert -- http://www.PowerDNS.com Versatile DNS Software & Services Trilab The Technology People Netherlabs BV / Rent-a-Nerd.nl - Nerd Available - 'SYN! .. SYN|ACK! .. ACK!' - the mating call of the internet
