This Green RevolutionImproving the yield of your network investment
eComm AmericaSan Francisco, CAApril 2010
Eric [email protected]@ericklinker
This Green RevolutionImproving the yield of your network investment
eComm AmericaSan Francisco, CAApril 2010
Eric [email protected]@ericklinker
Ding Dong the Witch is Dead
We’re not in Kansas Anymore
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StrongRegulator
CompetitiveMarketplace
Sustainable only if we meet the challenge of self-regulation
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“Publicity is justly commended as a remedy for social and industrial diseases. Sunlight is said to be the best of disinfectants; electric light the most efficient policeman.”-Louis Brandeis
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Discrimination is sometimes hard to justify…
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Rush hour on the yellow brick road
Neutral and Priority can Co-Exist
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• The road is neutral
• And still most cars give way
Self regulation, a two way street
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• Replace TCP for P2P transfers• Design Goals for this new protocol:
– Yield capacity to any other application– Keep the bottleneck full– React in 1 RTT
• Congestion control approach:– Continuously estimate one-way delay– Separate queuing delay from propagation delay– Target a small value for queuing delay
We call this new transport “Micro Transport Protocol” or “µTP” (most commonly just “uTP”)
uTP creates a “Scavenger Service”Only idle capacity is utilized
25-50msExtreme gamers start to notice problem
50-100msGaming impact apparent
100-150msReal-time gaming degraded
200msVoIP stops working
250msGames become unplayable
Interactive apps seriously degraded
400-500msWeb browsing seriously degraded
UTPTCP
100ms limit30-50ms?
500ms Latency
Samples
Effects of uTP with Target of 100ms
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20072001 2005 2008
Internet 2 Research on QoS
Researchers form Plicto
BitTorrent buys Plicto, rebrands technology “uTP”
uTorrent 2.0 auto-updated to over 70M users
uTP deployed in 17M DNA clients worldwide
Testing begins in uTorrent consumer clients
LEDBAT WG formed in IETF, Microsoft and BitTorrent co-chair
uTorrent 2.0 (with uTP) declared stable
1M uTorrent Beta users surpassed
2009
BitTorrent outreach to other developers
2004
Status of uTP
2010
uTP Ambition – Consumers
• Don’t have to set bandwidth limits• Download speeds at parity (perhaps potential for “faster”)
Users don’t need to actively “manage” their clients
• Domestication on the home network• Internet connections less likely to suffer congestion
No ability for P2P from one user to harm another user
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Real Operator Benefits?
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MR
TG
• Networks can run “hotter” (with revised cap planning)
• Networks can now use capacity previously reserved
• VPNs and MPLS• Improved profitability or
reduced capex
• User complaints from P2P greatly diminish
All traffic (excl uTP)
uTP traffictime
• Can uTP help?• uTP “clips itself”• Networks can focus on non-uTP traffic• BitTorrent falls back on global peer network
What’s the Downside?
• Existing SNMP monitoring tools may not be adequate…• Channel utilization no longer an effective proxy for
congestion
Expense of diagnostic tools to quantify uTP traffic?
• When uTP is not really uTP…
What about people who implement uTP “gaming the system”?
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Market Saturation
Low High
The Emerald City
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• >75M monthly actives
• ~100% y/y growth
• Aggregate traffic > 1 EB/mo
• Est’d peak rate > 4 Tbps
* Share assumes dedicated BitTorrent software, not BitTorrent-capable software like
Opera web browsers and P2P clients from Limewire, Xunlei, and others.
Probably well over 200m active BitTorrent-capable clients
100 10k 1M >10M Active Clients
TGAP OZ
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…
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…
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Wish List of Self-Regulating Principles• Ensure any mgmt. practice is explicitly tied to
congestion (and be transparent – even about the congestion)
• Manage in a protocol agnostic manner• If you meter, meter fairly
• Grandma gets a discount• So does my vacation home
• Re-think caps no obv. link to congestion• Putting a kill-switch on every odometer won’t solve rush
hour• If you must – at least adjust for “inflation”
• Incent network friendly behavior• “nights and weekends”, uTP discounts
In the merry old land…
• Have a heart – Don’t discriminate
• Have a brain – Think about your customers
• Have courage – Embrace transparency
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Thank you
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