locality and service structure of popular web · pdf file1 1 © nokia siemens networks...

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1 © Nokia Siemens Networks Inernet Success Factors and Challenges / Joachim Charzinski / Sep. 2008Public

Locality and service structure of popular Web sitesJoachim CharzinskiNokia Siemens Networks

ITG Fachgruppe 5.2.1 14.Nov.2008Network Planning & Traffic Economics


Disclaimers

• The opinions stated in this presentation represent the author’s scientific views and are not necessarily identical to Nokia Siemens Networks’business directions.

• Trademarks are owned by their respective owners and used here only to illustrate things in context.


There are many ideas and questions around…

• service based charging for Internet traffic with DPI• distance based charging for Internet traffic

• QoS reservations for applications• end-to-end Ethernet pipes

• local breakouts and services• network based cacheing in access/aggregation networks• NAT dimensioning

• Web 2.0 “mashups” traffic characteristics

• strict packet filter configurations for security


Evolution of traffic relationsearly computertelephone

broadcast

multicast peer to peer

early Web

1

2

today‘s Web

What’s different?How much?

2


existingservice3

existingservice2

API

existingservice1

Web 2.0 Mashups

• re-mixing of existing services into new services

API

image source: flickr via http://metaatem.net/words/mashup

newservice B

client side mashup

server side mashup

newserviceA

API


Web inclusion versus mashups

AD BANNER

current train delays

advertisement banner server

data server

AD BANNER

current train delays

advertisement banner server

data server

“Classical” Web inclusion Mashup existingservice3

existingservice3

existingservice2

APIAPI APIAPI

newservice B

client side mashup

newservice B

client side mashup

• whole element included from remote service

• images, frames• advertisement servers, click-

through billing services, contents distribution networks

<li><img src="http://ad.de.doubleclick.net/ad/N3995.yahoo_DE/B3152413.7;sz=1x1;ord=1223414745?" width=1 height=1 border=0 style='display:none;'>

<script type="text/javascript" src="http://www.google.com/jsapi?key=ABQIAAAA3nuEoGKhRfKaTwhFg7OdgxS6mGdPc-RjK_luIMxI5IejX_bbThTmLSxjVS7PFK_Jwc8dOvCuFMqQOw"></script>

…

google.maps.Event.addListener(markers[46], "click", function() {…

• raw data included from remote services

• local data processing• maps, images, blogs/information


Outline

• Motivation• Measurements• Results


Internet measurement methods

• passive measurement– observe (aggregate) traffic from real users– lots of data, often statistically significant– only anonymized traces available / usable due to privacy legislation– no correlation back to user actions or Web sites visited– no full address visibility required for CIDR prefix investigations

Internet• active measurement

– injection of IP packets or TCP data transfers– measurement of Internet (not Web) characteristics

▪ latency, packet loss, re-ordering

• actively initiated measurements– defined Web workload

▪ list of elements to retrieve▪ list of sites to visit

– concentrate on service rather than packet level– observe latency, download speeds– analysis of IP addresses, networks and service structures

InternetURLList

Internet

CIDR Classless Inter-Domain Routing

3


Measurements used here• actively initiated measurements• visit 100 Web sites most popular in the US

according to alexa.com (06/2008)• visited homepages only• automated process: for each site do

▪ start packet trace▪ open browser to load home page▪ close browser after home page has loaded (or after 1min timeout)▪ stop and store packet trace

• observed measures– traffic (rates, volumes, number of packets)– locality structure (number of hosts, network prefixes, AS numbers, DNS SLDs)– analysis of CDN usage

103046

packets

492

unique hosts

234

unique NPs

157

unique ASs

2294100

connectionsSites

AS Autonomous SystemCDN Content Distribution NetworkNP Network PrefixSLD Second Level Domain 10 © Nokia Siemens Networks Inernet Success Factors and Challenges / Joachim Charzinski / Sep. 2008

Public

Internet

Different Notions of Locality

Hosts

server 1 server 2

server n

. . .

64.236.16.136

64.236.16.160

157.166.255.12

Client88.64.48.1

Organizations

. . .

akamai.net

doubleclick.netcnn.com

google.com

arcor-ip.netClient

Routing Domains (NPs, ASs)

network 1network 2

network n

. . .AS 3356

AS 1668

AS 5662

AS 3209

access network 88.64.0.0/14

64.236.0.0/16157.166.224.0/19195.50.128.0/18

204.160.0.0/13207.120.0.0/14

Geographic Locations

server 1 server n

server 2 client


Active and passive usage of services

loadingcnn.com

home page

loadingebay.com

home page

loadingwikipedia.orghome page

loadingweather.comhome page

• passive usage: Which sites are using this service?• active usage: Which services does this site use?


Outline

• Motivation• Measurements• Results

4


Locality example for a top Web site’s home page

client

Internet

xlink.net

Yahoo! homepage http://www.yahoo.com/30 connections298 kbytes15 hosts11 network prefixes9 ASsAkamai share: 8 hosts, 5NPs,

5 ASs, 3 DNS SLDs

loadingyahoo.comhome page


Page size and locality characteristics

DNSASNetworkHTTPNumber ofNumber of ConnectionsSize

11.7M

600k

943(Bytes)

107

22.94

1total

45

15.3

1max. conc.

21

8.24

1Hosts

284

62.2

2Requests

14

5.65

1Prefixes

1513max.

5.155.04average

11min.SLDsNumbers

0

0.2

0.4

0.6

0.8

1

0 50 100 150 200

ccdf

number

HTTP requestsconnections

max. concurrent conn.

number

10034

0

0.2

0.4

0.6

0.8

1

0 5 10 15 20 25

ccdf

number

HostsNPsASs

DNS SLDs

number

138


Content distribution networks (CDNs) allow loading more contents during the same time

LatencyData RateASsNumber ofPage Size

651k465k599kin Bytes

9.93.98.2Hosts

6.12.45.0

320k196k286kin bit/s

10.4with CDN9.2without CDN10.0Average (all)in sec

0

0.2

0.4

0.6

0.8

1

0 500000 1e+006 1.5e+006 2e+00

ccdf

Bytes downloaded for home page

sites using CDNssites not using CDNs

0

0.2

0.4

0.6

0.8

1

0 10 20 30 40 50 60 70

ccdf

Time to load home page in sec

sites using CDNssites not using CDNs

Total time to load home page in secBytes downloaded for home page0 500k 1M 1.5M 2M


20%

12%4% 2%

62%

AkamaiFootprintGoogleMirrorimagePantherCDN

68%7%

17%

3% 5% AkamaiFootprintGoogleMirrorimagePantherCDN

Usage of Contents Distribution Networks

CDN share of connectionsCDN share of total: 35%

CDN share of volumeCDN share of total: 46%

CDN domains in Arcor networkAkamai = akamai.net, akamaiedge.net, akadns.net, akam.net via arcor-ip.de, level3.netFootprint = footprint.net via level3.netGoogle = l.google.com via google.comMirrorimage = mirrorimage.net, instacontent.net, mirror-image.net via mii.net, ripe.netPanthercdn = panthercdn.com via ripe.net

*data sets used: Web top 100 home pages + Web top25 browsing sessions

5


Passive usage of services

loadingcnn.com

home page

loadingebay.com

home page

loadingwikipedia.orghome page

loadingweather.comhome page


Passive usage results

• typical popularity rank distribution known from contents

1

10

100

1 10 100

Num

ber o

f site

s us

ing

serv

ice

Service rankService rank

Rank distribution of service usage

0

2

4

6

8

10

12

14

0 20 40 60 80 100 120 140 160 180

Num

ber o

f NP

s se

en

Service rank

• heavily used services are more distributed

Service rank

Number of network prefixes observed per service


Outline

• Motivation• Measurements• Results• Conclusions


Web results summary• similar to the Internet itself, also the Web has become a

highly distributed infrastructure• most Web sites are realizing their service in a highly distributed way

– deliberate distribution of contents (CDNs)– service hosting– advertisement related element inclusion– mashup of Internet Web services

• consequences for network architectures etc.– service or distance oriented charging would be highly intransparent to users– explicit QoS support by admission control is practically infeasible for Web traffic– local caching in access or aggregation networks

▪ can cover only top sites▪ will have to interwork with multiple CDN services

– availability of whole service critical due to large number of components▪ loose coupling service model already employed on the Web

– dedicated security configurations hard to do without impact on important sites– large number of ports (~30) required simultaneously per user

(e.g. on NAT devices or firewalls)

locality and service structure of popular web · pdf file1 1 © nokia siemens networks...

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