On 26/01/15 7:45, Dave Taht wrote:
I am curious as to what aspects of bufferbloat I
cover more deeply in my upcoming talk at nznog this friday?
[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
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