[e2e] Changing dynamics
David P. Reed
dpreed at reed.com
Sat Feb 21 08:57:01 PST 2009
Most (not all) of these ideas seem to reflect the idea that we should
operate the net with a lot of internal buffering.
For example, if it were actually a frequent benefit to search *partway
back towards the source* rather than all the way back, to find a packet
that was dropped because of a transient queue growing because of a burst
of cross traffic, then what would that mean?
It would mean that the packets are not transiting the network in the US
with little or no delay other than hops*packet size*line rate (which
could be helped by lower hops or smaller packets, or upping line rate,
no memory required).
I do think there is a virtue to moving replicated content closer to the
endpoints. But that is a different thing, and has nothing to do with
routers and e2e protocols. That thing has to do with what we were
debating a few weeks ago: what Van Jacobson calls "content centric
networks" or what Akamai does at the app layer, or my point about
communications not having to be about information that begins with the
assumption that information is in "one place".
Pekka Nikander wrote:
> Given that the memory prices have been plummeting about 100x every
> decade for the last two or three decades while the long-haul
> communication prices only maybe 5-20x every decade, why do we still
> consider the memory in the forwarding boxes as ordered queues?
> If the network knew a little bit more about what it handles, instead
> of queues we could have opportunistic caches worth for several seconds
> or even minutes of traffic, couldn't we?. No longer need to wait for
> a full RTT to get a missed packet? No longer necessary to send
> packets out in the order received but better classified by latency
> requirements? Ability to wait for better radio conditions before
> bursting the next bucket of spam?
> Instead of trying to optimise some queues in an end-to-end fashion and
> fighting of whether the optimal queue size is 1 or 4, perhaps we
> should aim to keep the fibers bitted up all the time, and all of the
> memories filled with usable data? Isn't lit but idle fiber or powered
> but unfilled storage essentially waste?
> Or, when in 2018 I will drive to Fry's to buy my 100TB disk at $100,
> should I pick it pre-filled with a web cache, my favourite movies, or
> what? Or will still I wait for it the three months it takes to be
> filled at constant 100 Mb/s, my upstream Tier-2 apparently still
> paying maybe $1/Mb/month to its Tier-1 for transit (instead of the
> present $20/Mb/month)?
> Are we seeing a Content Wall joining the well-known Memory Wall?
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