This Green RevolutionImproving the yield of your network investment

eComm AmericaSan Francisco, CAApril 2010

Eric Klinkereric@bittorrent.com@ericklinker

This Green RevolutionImproving the yield of your network investment

eComm AmericaSan Francisco, CAApril 2010

Eric Klinkereric@bittorrent.com@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

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Status of uTP

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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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