On Tue, Apr 3, 2018 at 10:48 AM, Jesper Louis Andersen < jesper.louis.andersen@gmail.com> wrote: > On Tue, Apr 3, 2018 at 4:27 PM Michael Welzl wrote: > >> please, please, people, take a look at the ietf taps (“transport >> services”) working group :-) >> >> > I tried looking it up. It seems the TAPS WG is about building a consistent > interface to different protocols in order to get a new interface rather > than, say, the bsd socket interface. > > But my search turned up several drafts from the WG. Did you have one in > particular in mind? > > I think the major reason to implement new protocols inside UDP is mainly > due to a lot of existing devices out there, namely firewalls, NAT systems, > and so on. The internet is extending itself by successive patching of older > standards, rather than a replacement of older standards. I do note that > this is how biological systems tend to work as well, but I have no good > reason as to why that is what happens with internet standards where we in > principle could redesign things. But perhaps already deployed stuff makes > the systems susceptible to iterative patching. > ​Middle boxes are a huge problem. ​ > > The bufferbloat angle is also pretty clear: CoDel is a brilliant solution > but it requires you to change queues in the network. So it seems people are > trying to patch TCP instead, through something like BBR; again mimicking a > biological system. > ​​ > > ​To some extent: but BBR is in fact a breakthrough independent of bufferbloat (and in fact will induce > 1RTT of buffer, which is far from ideal). For example, BBR works tremendously better t​han loss based congestion avoidance algorithms in the face of high RTT/lossy networks, like those faced in satellites or the developing world. > ​To get to really good RTT's (with low jitter), you still need ​fq_codel (or similar). You just can't get there by hacking TCP no matter how hard you try... See both on their independent merits: it is part of the Elephant; it's easy to think your "solution" solves the whole problem, when it doesn't. I will cheer both fq_codel and similar flow queuing AQM's that may appear *and* BBR loudly. - Jim