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P2P: An ISP’s Point of View

Pablo Rodriguez Telefonica Research, Barcelona

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P2P Success…

P2P is everywhere...

P2P Telephony: Skype (or how to deal with NATs)

P2P TV: Joost is about to realize the dream of ubiquitous/personalized TV.

P2P File Delivery: bittorrent.com scales large file dissemination without having to wait for IP Multicast

P2P Data Syncing: backs up your data and keeps it in sync across all your computers, e.g. Groove

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Why…? We got tired of waiting for the network to support various

things:

— E2E IP Multicast

— Content-Based Naming Protocol

— Anycasting

— End2end reachability

Quickly experiment new ideas:

— no need to change all routers in the world or make an agreement with every single ISP in the world

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P2P Swarming & Routing Protocols

Packet Networks: Time MultiplexingTime Multiplexing

— Reuse the same channel across time

P2P: Space MultiplexingSpace Multiplexing

— Leverage unused resources across nodes in the network

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Can we integrate P2P swarming concepts with routing and use network coding to build a universal swarm?

Oviedo, Spain

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And as we all know . . .

ILLEGAL P2P is the largest bandwidth consumer in the Internet

Eye candy from cachelogic.com, 2005

BitTorrent

eDonkey

non-”P2P”

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But others think different… Paul Francis, 10th WCW.

Things are changing.And the numbers are showing so….

Down/Up Traffic

                                            

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June-06

Oct-06

Jan-07 March-07

June-07

Oct-07

1.07 1.1 1.13 1.17 1.25 1.37

Why….?

The battle for bandwidth and copyrights

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Two types of P2P:Illegal DownloadsCommercial

Downloads

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ILLEGAL P2P and ISPs…

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P2P and ISPs

In one sense, ISPs of course love it…

— Because a lot more customers subscribe for broadband

— Though they must be kicking themselves for not charging for volume during the P2P growth boom!

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Ultimately there are some fundamentals here

P2P protocols allow end hosts to pretty much fill their access bandwidth constantly

Total access bandwidth could exceed total backbone bandwidth by (very roughly) one or two orders of magnitude

In other words, the Internet is (or easily could be) over-subscribed.

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Difficulties

Increased traffic volume without increased revenue

— Users got a lot of value out of P2P but nobody got paid extra for it!

— Eventually, ISPs will reach customer saturation, and then…

Conflicts between Overlay and Underlay

— P2P topologies are not aware of the ISPs economics.

— This makes P2P traffic to be routed over expensive transit links.

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Overlay vs Underlay Conflicts

Client/Server Economics

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P2P Economics

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Solutions

Filter P2P Traffic

— Reduces access revenue

Add caches

— Expensive to maintain, legal problems

Keep traffic within ISP

Establish new ISP relationships

— Flattens the Internet

Redirect traffic to less expensive peering points

P2P traffic could go through unwanted links

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SPRINT/LEVEL3

Access ISP

Telefonica Backbone

Tel Spain

Tel Brasil

Transit ISP

Backbone

Access ISPs

Transit ($$$)

P2P P2P

P2P

Other Backbone

(II)

Peering ($$)

Other Backbone

(I)

Peering ($)

Can ISPs take advantage of clients within?

Perc

en

tag

e o

f To

rren

ts

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Percentage of local Peers

-Two modes:One for all local swarmsAnother for all foreign swarms

Potential for locality for Telefonica

-More than 50% of traffic could stay within

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What about LEGAL P2P?

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Several Content providers are using legal P2P networks to reduce their distribution cost to zero

The most popular case is the BBC.

However, they are basically pushing the distribution cost to the ISP…

Content Providers are moving fast…

BBC iMP – Legal P2P Distribution

• Content Trial Sep 05• Sky announced competing offering• Every major broadcaster evaluating P2P

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And ISPs are already complaining…

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Moral:One way or another, legit content providers have to pay for distribution and current legal P2P models do not fit well ISPs

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and… one way to keep everybody happy is if ISPs deploy their own legal P2P technology

Telco Managed P2P

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Why does it makes sense? ISPs can control the user experience and how

the p2p traffic flows in his network

ISPs can engage in the content distribution cycle

Removes content distribution hassle from Content Providers

Integrates well with existing IPTV solutions

-

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Massive Data Centers NOW

data centersdata centers

P2PP2P

Capital intensive

Huge energy consumption

Far from the end users

Capital intensive

Huge energy consumption

Far from the end users

Uncoordinated

Only statistical QoS

Poor use of resources

— Random topologies

— Simplistic scheduling

Uncoordinated

Only statistical QoS

Poor use of resources

— Random topologies

— Simplistic scheduling

I am just a

process

I have steel walls

a h

ug

e

gap

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Distributed Nano data centers using set-top-boxes

power & cooling for free

decent CPU & storage

predictable behavior

central control

power & cooling for free

decent CPU & storage

predictable behavior

central control

A set-top-box provides

… all we need to do is organize them a bit!

One Real Example: Imagenio P2P

homegateway STB

PC

TV

DSLAM

customer premiseTV

head end

ISP

IP MulticastInternet phone

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Internet (1 Mb/s)

VoIP

IPTV (5 Mb/s)1-2 channels

Last mile(6 Mb/s)

1Gb/s

6Mb/s

Joined work with Cambridge Univ and KAIST

P2P for Past Scenes: VoD Server Savings

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(no p2p)

(p2p)

Conclusions P2P has provided a great opportunity to deploy new

applications

There is a lot of potential to integrate P2P swarming solutions in routing (and use network coding to avoid scheduling problems)

However, the economics are still not clear and interactions with ISPs are non-optimal. P2P systems will need to adapt.

Telco-Managed P2P systems provide lots of opportunities to scale IP-TV services and a stable P2P ecosystem

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