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Why the future of the Internet is not multimedia, and
other high heresies
Mike O'Dell, UUNET
Multimedia seminar, 2/26/97
The "long view": multimedia is not what the Internet will be about.
(Maybe not vindicated in next 3-5 years, but certainly in the long run.)
High heresy #1: the future of the inet is not multimedia
- not "just like" anything else
- attempts to migrate traditional media to inet are
failing. (radio is not a talking newspaper; TV is not radio with
pictures.) It's a new medium.
- packets don't carry "sensory analog" traffic well
- impications for e-commerce, e-advertising?
- too expensive
- long haul infrastructure too expensive; free unlimited
bandwidth not coming (who remembers "power too cheap to
- fast access to local caches/content: maybe. (Long
haul is up to 3 orders of magnitude more expensive to
deploy) So @Home's model may be viable. Jury still out.
- Corollary: (Content providers will have to accept
that in order for
their content to be seen, it will have to be cachable!)
- "local" vs "long distnace" internet access???
- technology growth
- second derivative is wa positive. "If you
aren't scared, you don't understand." [QUOTE]
- UUNET-2000: 50 terabits; today: 5 gbits; look for 1000x
growth over 3 years.
- Voice: $250B "niche"; grows only with human population, driven by
population demographics (like other "human centric" businesses).
Little value in adding voice quality.
Fundamental shift in bandwidth consumption
- Formerly, growth driven by "mothers day"
- Now: hungry silicon cockroaches! (computing power that attracts
- short,fast, bursty vs. long,slow,smooth channel use
- limiting factor for growth: basically, rate of melting sand!
- pecking order
- fax machines, cellphones: blew out the North Amer
- PC+modem: blowing out switched capacity
- inet backbones: eat long haul capacity
- webphones and digital daytimers: eat wireless capacity?
(huge fraction of cell phone calls are to set up other
meetings, etc., not conversations!) "Network externality"
effect will cause this usage to overwheml multimedia.
- capacity is getting used up as fast as it's provided
- web content will be examined by robots, only shown to
humans after comparison shopping! Automatic
aggregation services willdominate.
- therefore existing advertising models are broken...
- cockroaches will be empowered by owners to spend money.
- conclusion: follow the money
- Comm networks 21st c. will be built for cockroaches
- human/cockroach symbiosis
Heresy #2: multicast everywhere
RSVP and classic multisource mcast--no way.
- bad scaling; "The only problem is scale; all other problems inherit
from that." (O'Dells Problem Statement) [QUOTE]
- no business model. (Uunet is spending >$300M
next year for infrastructure! Similarly AOL...)
- parts may be salvageable for large scale use
Heresy #3: all you need is IP routers: guided tour of UUNET
- No traffic mgmt except on toy topologies
- classic IP dest-only fwding induces "super-aggregation" f IP
traffic; can't disaggregate them. Result is unbalanced network;
Controlling traffic "spread"
is just not feasible -- only realizes small percentage of network
- capacity and bandwidth are different
- hard to add "targeted" capacity
- BW+BW=capacity; but capacity is "incoherent" (basically,IP can't
convert it into ordered-delivery bandwidth)
- deep systemic redundancy
- redundancy in the switches (implementation)
- redundancy in routing maps (architecture)
- little redundancy in IP routers
- all hardware in "lights-out, hands-off" locations, costs
at least $1K to get a human to go do something.
- cost of ownership (operating cost) vs. capital. Be careful
which you optimize!
- 4 layer network, top to bottom:
- collector networks: a lot of muxing to bring customer IP
traffic to network core
- IP routing: fully redundant mesh; no customer-specific
state in core routers; protected at edges only (route
filters). Optimized for fast IP forwarding, and that's
all. Two full-meshes with spoke "leaves" interconnected
- transit switching: map large traffic flows onto traffic
fabric in a way that's invariant to IP topology; "surgical
precision" for adding transmission capacity. Full
dynamic routing with constraints.
- transmission facilities (TDM bandwidth, telephony-to-TTL);
OC12c, OC48 "soon" (year-end 97)
- Observation: traffic flow engineering is an
economic optimization problem. Collapsing the above
layers removes most of the knobs that allow this problem
to be solved.
- "Metro architecture" (now being deployed):
- OC-12 "metro rings" (july 97); above "superhubs" are situated
around the ring (OC48: year end 97)
- applies backbone architecture recursively
- regional traffic engineering
- segregation of data, control, routing "planes"; no reason
to collapse these functions into one box
- "Massively Parallel backbone" (tm)
- 500 Gbits trunk, 2-10 Gbits strands, 20-50 Tbits aggregate
- building blocks: 16-port OC48c switches, DWDM (wave
division muxing) puts
multiple OC48c on a
fiber, wavelength-agile lasers on line modules
- take the OC48c switches, stack them up, stack another
bunch of them up perpendicular, and you get something that
looks like a 3D version of the Myrinet crossbar using
Intersting open problems... (from Q&A session)
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- Simluation and modeling: traditional network modeling/simulation
techniques break at this scale. What do you measure/model? What
behaviors or variables are interesting? The "phenomenology" of
this scale of packet network is just not well understood. (You
can observe things like "large Net events": Olympics,
Superbowl, new release of Netscape...)
- "Internet weather report": what does it measure?
- "Why (internet) caches are impossible"? (someone else's talk)
- Someone asked "What do you think AOL's problem is?" He declined
to comment, saying "There but for the grace of God..."