On 12. okt. 2013, at 08:28, Mikael Abrahamsson <[email protected]> wrote:
> On Sat, 12 Oct 2013, Michael Welzl wrote: > >> My question is, why is none of this happening? > > My guess is that the rule to always deliver packets within a stream in order. > If packets within the same stream have different DCSP values, there is a risk > that they will go into different queues and they might be delivered out of > order. A lot of applications that do real-time will have a PDV buffer, but > won't have much of a out-of-order buffer. If a packet with sequence number 10 > arrives after sequence number 8, packet number 9 is often assumed to be lost. > > AQM is not widely deployed at all on the Internet as it is today, and a lot > of devices will just have 4 different queues. Also as you say below, putting > packets into different queues might mean they compete with other traffic and > you might get packet loss due to that. > > It would of course be of interest going forward to look into your proposal. > AQM/Bufferbloat movement could perhaps benefit from this, but the current > thinking is to make sure that all streams get equal access to the media with > minimal influence between them, not that much to decide what packets within a > stream to select for drop. Thanks, that's about what I guessed... strange, a bit, given that it's not hard to show quite large quality gains if packet priorities within a stream (five-tuple) are honored, and doing per-5-tuple things near the edge doesn't seem all too unusual to me... So indeed it wasn't a proposal, I was just wondering why it's not done. Maybe not enough interest from the parties involved (because application developers are not usually the same people that build middle-boxes) Cheers, Michael
