UDP vs. TCP distribution [was: Re: [e2e] Can feedback be generated...]

[Jon Crowcroft]

In message <20010305230102.1BAF88A3 at sean.ebone.net>, Sean Doran typed:

 >>| fact is theres few facts about any of this, jusdt lots of opinion.
 
 >>Well, yeah, but Jon, given that the Internet is heterogeneous,
 >>anisotropic, expanding, and mutating, it is really hard to be
 >>anything but anecdotal, since even the most comprehensive data
 >>set (one that defeats the observer problem (i.e., in the absence
 >>of isotropism, how do we know what things look like "over there"?)) 
 >>will quickly grow stale.

a few of us actually try to do some measurements in the real world -
before we do to many, we thoguht we would see if some other people had
some - there is a LOT on web, a LOT on voice over IP now, and a lot of
it is done over a fairly well characterised set of IP paths globally,
despite what you say about the heterogeneity - sorry, but the fac t is
 that when it comes to games, there isnt, as far as we can tell, but
we thought we;d ask.
 
 >>| go look at the original bell labs papers on interative audio RTTs :
 >>| that was just opinion too - when we get to games (pace, Cheriton) same
 >>| applies in spades

 >>Are you arguing on the question of whether opnion can be "good enough",
 >>or on the question of whether something much more strong than opinion
 >>or localized (in space and time) measurements can be obtained with
 >>an affordable amount of effort?

look at vern's work on characterising end to end paths, look at
sculzrinne, and bolot's workl on charcartiering delay jitter and its
effect on voice, look at abundent work on zipf law and not for web
page download size/time, etc etc etc

where is the _equivalent_ _experimental_ data for games, please?

the point is that a lot of early work in this area (50s,60s, itu
standards definitions for toll quality speech) was based on LAB
experiments, often with small, culture specific samples. a LOT of
recent internet measurement work is based on real world data, which is
NOT magic, not impossible (its hard work, and has to be incremental,
painstaking, and very careful, but there is a lot) - we just wanted to
see where the work had got to in one more part of the space.....

 >>[in a long-ago CIDRD wg meeting when they were contentious]
 >>smd: well, that's just my opinion
 >>voice in crowd (tli? postel?): and we're ALL entitled to Sean's opinion
 
thanks, given that sean's comments are heterogeneous, anisotropic and
expanding and mutating, i guess we are.

 cheers

   jon