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Internet Inter-Domain Traffic. Craig Labovitz, Scott Iekel-Johnson, Danny McPherson, Jon Oberheide, Farnam Jahanian. Presented by: Kaushik Choudhary. Outline. Introduction Data Collection Methodology ASN Traffic Analysis Application Traffic Analysis Internet Size Estimates Conclusion.
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Internet Inter-Domain Traffic Craig Labovitz, Scott Iekel-Johnson, Danny McPherson, Jon Oberheide, Farnam Jahanian Presented by: Kaushik Choudhary
Outline • Introduction • Data Collection Methodology • ASN Traffic Analysis • Application Traffic Analysis • Internet Size Estimates • Conclusion
Introduction • “The Internet has changed dramatically over the last five years” – Cliché. • Internet traffic has gone over the roof due to:
The changes • Content providers (like Google) build their own global backbones. • Cable internet service providers (ISPs) offer wholesale national transit. • Transit ISPs offer content distribution networks (CDNs).
The changes Transition from: Fig 1: Traditional Internet logical topology.
The changes to: Fig 2: Emerging new Internet logical topology.
What is new in this paper • Most studies about traffic have focused on BGP route advertisements, DNS probing, industry surveys, private CDN statistics etc. • In this paper, the authors studied over 3000 peering edge routers of 110 participating internet providers over two years.
Outline • Introduction • Data Collection Methodology • ASN Traffic Analysis • Application Traffic Analysis • Internet Size Estimates • Conclusion
Data Collection Methodology • Data collected by probes of a commercial security and traffic monitoring platform instrumenting BGP edge routers. • Each probe exports traffic flow statistics that includes traffic per BGP AS, ASPath, network and transport layer protocols, countries, etc. independently to form different datasets.
Data Collection Methodology Fig 3: Netflow network probes.
Challenges in Data Collection • Commercial privacy concerns. • Misconfiguration of probes (resulting in wild fluctuations in daily traffic). • Decommissioning of edge routers! • Decommissioning of older probes and addition of new ones!
Need for Data Aggregation • Wild fluctuations in the data. • Heterogeneity of the providers. • Ratios and percentages were consistent despite the fluctuations.
Data Aggregation • The probes calculated average traffic volume every five minutes for all members of all datasets throughout every 24 hour period. • They also calculated the average volume of total inter-domain network traffic. • Finally, the daily traffic volume per item and network total were used to calculate the daily percentage.
Data Aggregation • Calculation of weights: where, = Weight of participant i on day d. = Router count for participant i on day d. N = All study participants.
Data Aggregation • Calculation of weighted average percentage: where, = Weighted average percent share of traffic for A on day d. (𝐴) = Each provider’s measured average traffic volume for A on day d. = Total average inter-domain traffic for day d. A = Traffic attribute like ASN, TCP port, country of origin, etc.
Data Defects and Validation • The probes did not detect traffic over peering adjacencies between enterprise business partners or in cases of similar agreements. • The data collected was validated through private discussions with large content providers, transit ISPs and regional networks.
Outline • Introduction • Data Collection Methodology • ASN Traffic Analysis • Application Traffic Analysis • Internet Size Estimates • Conclusion
ASN Traffic Analysis Table 1: Traffic contributors by weighted average percentage in July 2007.
ASN Traffic Analysis Table 2: Traffic contributors by weighted average percentage in July 2009.
Trends • Data from July 2007 is compliant with textbook diagrams of internet topology. • Changes in commercial policy and traffic engineering have drastically impacted shares in Internet inter-domain traffic.
Trends Table 3: Providers with most significant inter-domain traffic share growth in 2007-2009.
Google Trends • Google, a content provider, now rivals global transit networks and enjoyed the highest growth. • Providers and the data collected suggest that Google’s huge growth may be ascribed to the acquisition of Youtube.
Google Trends Fig 4: Google inter-domain traffic contribution.
Comcast Trends Consumer Content Fig 5: Comcast inter-domain traffic contribution.
Comcast Trends • Majority of the traffic growth in Comcast came from transit traffic. • What did Comcast do? • Consolidated regional backbones into a single nationwide network. • Rolled out a consumer product called “triple play” (voice, video, data). • Began offering wholesale transit, cellular backhaul and IP video distribution!
Outline • Introduction • Data Collection Methodology • ASN Traffic Analysis • Application Traffic Analysis • Internet Size Estimates • Conclusion
Application Traffic Analysis • Applications could be identified from TCP/UDP port numbers but: • Applications could use non-standard ports. • Port-based classification only accounts the control traffic and not the often random port numbers associated with subsequent data transfer. • The authors obtained validation data from five cooperating provider deployments in Asia, Europe and North America.
Largest Applications Table 4: Top applications by weighted average percentage.
Largest Applications Table 5: Average application breakdown in July 2009 across five consumer providers.
Application Traffic Changes Fig 6: Distribution of weighted average percentage of traffic from well known ports (July).
Application Traffic Changes • TCP and UDP combined account for more than 95% of all inter-domain traffic. • In July 2007, 52 ports contributed 60% of traffic. • In July 2009, 25 ports contributed 60% of traffic. • What’s happening here?
Application Traffic Changes • Internet application traffic is getting migrated to a smaller set of ports and protocols. • Microsoft migrated all Xbox Live traffic to use port 80 on June 16, 2009. • One reason for this is that majority of firewalls allow HTTP traffic. • The other reason for this trend is the dominance of
Applications Exhibiting Growth • Much of the growth in web data is due to video (Youtube uses progressive downloading). • Growth in video traffic is due to the introduction of services like Hulu, Youtube, Veoh, etc.
Applications Exhibiting Growth Obama! Fig 7: Change in weighted average percentage of video protocols.
Applications Exhibiting Decline • P2P dropped by 2.8% between 2007-2009. • Possible reasons • Migration to tunnelled overlays. • Use of P2P encryption. • Stealthier P2P clients and algorithms. • Network operators however, suggest P2P traffic may have migrated to alternatives like direct download and streaming video.
Outline • Introduction • Data Collection Methodology • ASN Traffic Analysis • Application Traffic Analysis • Internet Size Estimates • Conclusion
Internet Size Estimates Fig 8: Independent inter-domain traffic volumes vs calculated aggregate ASN share..
Internet Size Estimates • The authors solicited verification data from twelve large providers and content sites. • The slope of the above curve means that a 2.51% of share of all traffic means 1 Tbps of traffic. Extrapolating this way, • This was in July 2009 (before the release of iPad!).
Internet Size Estimates • In other analyses, the authors report the annual growth rate of the internet to be about 44.5% and the monthly traffic volume to be about 9 exabytes ( = 9 million terabytes!)
Outline • Introduction • Data Collection Methodology • ASN Traffic Analysis • Application Traffic Analysis • Internet Size Estimates • Conclusion
Conclusion • This paper is the first longitudinal study of Internet inter-domain traffic. • It identifies a significant ongoing evolution of provider interconnection strategies from a hierarchical to a more densely connected model. • Most internet content is migrating to a relatively small number of hosting, cloud and content providers.
Conclusion • Google is the largest contributor to Internet traffic growth. • Majority of inter-domain traffic has migrated to a relatively small number of ports and protocols. • As of July 2009, the inter-domain traffic peaks exceeded 39 Tbps and were growing at 44.5% annually.