Hi Dave, On 26/01/15 7:45, Dave Taht wrote:
I am curious as to what aspects of bufferbloat I should cover more deeply in my upcoming talk at nznog this friday? [... and] [t]alk abut new stuff going on, and wifi, if desired... talk more to bandwidth management and traffic engineering tools,
I think at this point there's pretty reasonable understanding of how bufferbloat happens -- and less understanding of how to practically deal with it, especially within an operator network which faces a variety of latency challenges, eg, cross-town, within-NZ, various distances outside US, satellite. Clearly the transfer speeds for some of those are improved by using non-trivial buffers, and the transfer speeds of others are made drastically worse by having too much in flight. I suspect many operators have a mix of all of them. (Obviously if the customer has their own buffer bloat issues the operator can't magically fix things completely -- but "do no harm", ie don't make things worse, seems a reasonable aim.) If you had any insights on, eg, how bufferbloat interoperated with upstream provider policing policies and how to deal with that that'd likely be of interest too. I'm guessing is "shape within the upstream policing envelope" -- but that's sometimes easier said than done if the upstream providers policing is very sensitive to instantaneous bursts of packets. And any advice on defining such operator shaping/policing policies to make them less likely to cause adverse behaviour (eg, being less sensitive to packet arrival time of the "last packet of the burst arrived 1ms too soon, so we threw it away, have a nice day" variety).
there is someone here today doing mikrotik training, and as yet only mikrotik only supports SFQ, not fq_codel. [...] I have a pair of slides on the differences between SFQ and fq_codel.
I think it would be great to talk about this too. And also if there's any thing that can be done with the Mikrotik (and hence SFQ) to mitigate the disadvantages. There are lots of Mikrotiks deployed in New Zealand, including a whole bunch on not-entirely-predictable-bandwidth (unlicensed) multi-mile radio links.
And so on. I'm here all week... I've borrowed a NZ vm, run a few experiments worldwide, am fiddling with some parameters...
I think many would be interested in any parameters that worked well for in-NZ, to Australia (relatively low latency, several CDNs/Amazon/etc there), to USA (much of content there) and to Europe. So any results you find would be great. Plus of course if there are specific things that, eg, operator helpdesks should be recommending to customers that complain of transfer speed issues that seem like bufferbloat related that'd also be useful. But could possibly just be some slides pointing to useful resources for end users. Ewen