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Re: [RRG] Why delaying initial packets matters
On Feb 12, 2008, at 12:54 AM, Lars Eggert wrote:
Sure, and the concern isn't that apps and transports can't deal with
these events when they happen. However, dealing with these events
usually has some negative performance impact.
Yes. And if the negative performance impact is sufficiently great,
software and/or protocols and/or expectations are modified. Or at
least they have been in the past.
The question is if any of the proposed layer-3 extensions increase
the probability of these events happening to a degree where user-
perceived performance is significantly impacted.
And the answer may well be "no, they don't",
I'm sure they do. Once again and with feeling: TANSTAAFL.
I'm a bit confused. I thought we're talking here about modifying a
key component of the underlying Internet architecture for the long
term. Such modification will have both positive and negative
impacts. The question isn't whether or not there will be an impact,
rather the question is (or should be) does the benefit outweigh the
Conceptually, as far as I can tell, we have a tradeoff. All things
being equal and relative to each other:
1) push-based systems will
a) not significantly increase latency/packet loss
b) be less scalable
c) allow less dynamicity
2) pull-based systems will
a) increase latency/packet loss, at least for the first packet of a
b) be more scalable
c) permit more dynamicity
Does anyone disagree with these assumptions?
but I'd be good to back that statement up with data.
I agree data should be collected and loudly applaud the efforts of
Dino et al. in writing actual code (I personally don't trust
mathematical models as long ago I saw one too many models
demonstrating how ATM was a perfect answer, regardless of the
question). However, from a conceptual point of view, I don't see how
we can get away from the tradeoffs I mention above. Whether or not
you find option (1) or option (2) acceptable will likely largely
depend on the assumptions you make going in -- we can all come up with
scenarios that are unacceptable for either option.
From my perspective, looking at how the Internet has evolved over
time, scalability and dynamic behavior have been areas in which we've
been bitten time and time again. We continue to see increased
deaggregation. We continue to see increased growth. We continue to
see increased dynamic behavior. We also see increased bandwidth,
cheaper memory, faster processors, etc. I don't see these changes
reversing or even slowing down over time. Thus, it seems to me we
should anticipate and optimize for these changes instead of optimizing
for the way things have been.
However, with all that soapboxing done with, I freely admit I'm not
half as bright as most of the people on this list and it is likely I'm
missing something fundamental. I'd be appreciative if someone could
explain it to me (using small words)...
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