Deconstructing the KaZaA Network

Matei Ripeanujoint work with Nathaniel Leibowitz and Adam Wierzbicki

P2P Impact: Widespread adoption

KaZaA – 200 millions downloads (3.5M/week) one of the most popular applications ever!

Number of users for file-sharing applications (www.slyck.com, March’03)

Surveys: 25-30% of all customers at large ISPs use P2P file-sharing systems

 

FastTrack 4,443,120

iMesh 1,385,199

eDonkey 623,097

Cvernet 528,750

DirectConect

136,552

Blubster 97,128

Gnutella 92,678

P2P Impact (2): Huge traffic

P2P generated traffic now dominates the Internet load Internet2 traffic statistics UChicago estimate (March ‘01): Gnutella

control traffic about 1% of all Internet traffic.

Cornell.edu (March ’02): 60% P2P

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Feb.'02 Aug.'02 Feb.'03

Other

Data transfers

Unidentified

File sharing

Recent studies

Three recent measurement studies on Kazaa traffic:

Are File Swapping Networks Cacheable? Characterizing P2P Traffic, N. Leibowitz, et all, (WCW7 Aug 2002)

Analyzing Peer-to-Peer Traffic Across Large Networks, S. Sen, J. Wang, (IMW, Nov. 2002)

An Analysis of Internet Content Delivery Systems, S. Saroiu, K. Gummadi, R. Dunn, S. Gribble, H. Levy (OSDI, Dec. 2002)

Data collection

Collect traces at border routers UWashington, Tier 1 ISP (AT&T?), large Israeli ISP

Identify (and log) Kazaa traffic based on:

port number (1214) content of HTTP request

Question 1:

What is the overall bandwidth impact?

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Bandwidth repartition

UWashington measurements Web = 14% of TCP; P2P = 43% of TCP P2P now dominates Web in bandwidth consumed

UW data, June 2002, Source: Saroiu & all.

WWW Kazaa

inbound outbound inboundoutboun

d

1.51TB 3.02TB 1.78TB 13.6TBUW data, June 2002, Source: Saroiu & all.

Inbound vs. Outbound traffic

UWashington acts like a huge content server: outbound (served) traffic 7.6 times larger than inbound traffic

Residential ISP: the situation is reversed as inbound traffic is more than 5 times larger than outbound

Question 2:

How do the objects shared look like?

File size characteristics

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File size (bytes)

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Possible file ranges: 10KB-100KB pics 1MB-5MB songs 10-200MB apps, video clips > 500MB movies

Question 3

What is the file popularity distribution?

Terminology: Download session: downloading one chunk

of the file in a single HTTP session Download cycle: a complete download of a

file

File popularity distribution

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10% most popular files generate 60% of the download cycles

1% (or about 3,000) most popular files generate 25% of the download cycles

Question 4:

How is consumed bandwidth use distributed among objects?

Traffic distribution - files

Compare to UWashington traces where 1% most popular objects responsible for ‘only’ 50% of bytes transferred

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1% most popular files generate 80% of the traffic

0.1% most popular files (about 300) generate 50% of the traffic

Costs …

Generated Traffic

Cost

Israeli ISP Kazaa Inbound 68GB $52

UWashington

Kazaa Outbound

360GB $277

Uwashington

Kazaa Inbound 25 GB $19

Uwashington

Web Inbound 36GB $27Assumptions: OC3 line at $40K/month 5 day logs extrapolated to one month

Cost to provide access to the most popular object for a month

Traffic distribution vs. file size

60 % of the bytes downloaded but only 5% of download cycles correspond to large (movie) files

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File size (bytes)

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fic)

% of downloads% of traffic% of files

Question 6:

Content dynamics and caching performance

Content dynamics

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per day per hour

Content dynamics (2)

How stable is the set of most popular files?

About 30% files remain popular over long period of time

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Ideal caching performanceTheoretical cache byte hit ratio

for various traffic volumes

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Achieved caching performance

Significant savings: File hit rates of 30-35% Byte hit rates 50-60% P2P traffic is more

cacheable than Web traffic

But, it takes long time to warm-up caches (weeks)

Question 7:

Virtual relationships between users

Outliers filtered out

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Word co-occurrences

Film actors

LANL coauthors

Internet

Web

Food webPower grid

Small world data-sharing graph

Data-sharing graph: Nodes == Kazaa

Users Link two users

that have similar activities (download the same files)

Future questions What savings can be realized without in caching

data but only redirecting requests to local users? What can one say about the overall characteristics

of the network (number of users, number of files, distributions) knowing only data logged by one ISP.

Constraint: Law makers may cause P2P traffic to vanish However this will lead to a new research question: How will

the sudden disappearance of 60% of Internet traffic affect the Internet?

Your questions

Thank you

Goals

High-level questions: What is the impact of these new content delivery

systems on the Internet and on ISPs? What are the characteristics of the Kazaa traffic?