Today’s Internet [1] differs significantly from the one that is described in popular textbooks [2], [3], [4]. The early commercial Internet had a strongly hierarchical structure, with large transit Internet Service Providers (ISPs) providing global connectivity to a multitude of national and regional ISPs [5]. Most of the applications/content was delivered by client-server applications that were largely centralized. With the recent advent of large-scale content distribution networks (CDNs), e.g., Akamai, Youtube, Yahoo, Limelight, and One Click Hosters (OCHs), e.g., Rapidshare, MegaUpload, the way the Internet is structured and traffic is delivered has fundamentally changed [1].
Today, the key players in the application and content delivery ecosystem, e.g., Cloud providers, CDNs, OCHs, data-centers and content sharing websites such as Google and Facebook which often have direct peerings with Internet Service Providers or are co-located within ISPs. Application and content delivery providers rely on massively distributed architectures based on data centers to deliver their content to the users. Therefore, the Internet structure is not as strongly hierarchical as it used to be [1].
These fundamental changes in application and content delivery and Internet structure have deep implications on how the Internet will look like in the future. Hereafter, we describe how we believe that three different aspects of the Internet may lead to significant changes in the way we need to think about the forces that shape the flow of traffic in the Internet. Specifically, we first describe how central DNS has become as a focal point between application/content providers and ISPs. Next, we discuss how software-defined networking may change the ability of many stakeholders to influence the path that the traffic belonging to specific flows will follow across the network infrastructure. Finally, we discuss how the distributed nature of existing application and content delivery networks will, together with changes within the forwarding/routing, enable much more advanced handling of the traffic, on a much finer granularity compared to the current Internet.
Challenge 1: DNS and Server Redirection
The Domain Name System (DNS) was originally intended to provide a naming service, i.e., one-to-one mappings between a domain name and an IP address. Since then, DNS has evolved into a highly scalable system that fulfils the very stringent needs of applications in terms of its responsiveness [6,7,8]. Today, the DNS system is a commodity infrastructure that allows applications and content providers to map individual users to servers. This behaviour diverges from the original purpose of deploying DNS [10]. As application and content delivery infrastructures control how DNS is used to map end-users to their servers, the transport network, namely ISPs, has very limited control as to how traffic flows across the Internet [31]. Note that the case of DNS is a specific instance of a more general class of mapping systems for networked applications, such as trackers used in P2P or Locator/ID split approaches, e.g., LISP. Whatever the actual mapping system being used, the use of DNS by application/content providers is a sign that network-aware application optimization approaches are needed. P4P as well as Application-layer Traffic Optimization (ALTO) are possible solutions for this. Direct CDN-ISP collaboration is another way of ensuring that the application side and the network collaborate to provide the best possible service to the end-users in a cost-efficient manner [32].
Challenge 2: Software-defined networking
Applications and content are not the only place where an Internet (r)evolution is taking place. Thanks to a maturing market that is now close to “carrier grade” [13,14,15,16,17], the deployment of open source based routers has significantly increased during the last few years. While these devices are not competing with commercial high-end switches and routers available with respect to reliability, availability and density, they are fit to address specialized tasks within enterprise and ISP networks. Even PC-based routers with open source routing software are evolving fast enough to foresee their use outside research and academic environments [18,19,20].
The success of open-source routing software is being paralleled with increasing virtualization, not only on the server side, but also inside network devices. Server virtualization is now followed by network virtualization, which is made possible thanks to software-defined networking, e.g., OpenFlow [21] that expose the data path logic to the outside world. The model of network devices controlled by proprietary software tied to specific hardware will slowly but surely be made obsolete. Innovation within the network infrastructure will then be possible. A decade ago, IP packets were strictly following the paths decided by routing protocols. Tomorrow, together with the paths chosen by traditional routing protocols, a wide range of possibilities will arise to customize not only the path followed by specific traffic, but also the processing that this traffic undergoes. Indeed, specific actions that are statically performed today by specialized middleboxes placed inside the network, e.g., NAT, encryption, DPI, will be implemented on-path if processing capabilities happen to exist, otherwise the traffic will be dynamically redirected to close-by computational resources. This opens a wide range of applications that could be implemented almost anywhere inside the network infrastructure.
Fusing the transport network and applications/content
As content is moving closer to the end-user for improved quality of experience and the infrastructure opens up to unprecedented control and flexibility, the old business model of hierarchical providers and customer-provider relationships is hardly viable. Nowadays, delivering applications and content to end-users is becoming a less and less profitable business, except for the few able to capitalize on the revenues from advertising, e.g., Google, Facebook. On the other side, network infrastructure providers struggle to provide the necessary network bandwidth and low latency for these applications, at reasonable costs. The consequence of more and more limited ISP profit margins is a struggle between content providers and the network infrastructure to gain control of the traffic.
This struggle stems from fundamental differences in the business model of applications/content providers and ISPs. Today, application/content providers, for example through DNS tweaking, decide about the flow of the traffic by properly selecting the server from which a given user fetches some content [8,22,23]. This makes application/content delivery extremely dynamic and adaptive. On the ISP side, most of the traffic engineering relies on changing the routing configuration [24,25,26]. Tweaking existing routing protocols is not only dangerous, due to the danger of mis-configurations [27], routing instabilities [28] and convergence problems [29,30], but is simply not adequate to choose paths at the granularity of applications and content.
Industry and academia must join forces to address the challenges posed by the evolving Internet. We believe that the three research areas above need critical input from the community in order to enable a truly content-centric Internet. First, even after more than two decades of deployment and evolution, the DNS is still poorly understood. The DNS is much more than a naming system, it is a critical mapping system and a critical point in the application/content distribution arena. Second, software-defined networking opens a wide range of possibilities that would transform the current dumb pipes of the Internet core into a flexible and versatile infrastructure. Further, software-defined networking researchers has the ability to allow injecting intelligence inside the network without having to think about how it will affect a whole range of legacy protocols.
One way to go is to enable the different stakeholders to work together, e.g., enable ISPs to collaborate with application/content providers [31,32]. This can be achieved for example by exploiting the diversity in content location to ensure that ISP’s network engineering is not made obsolete by content provider decisions [31,32] or the other way around. Another option in which we believe is to leverage the flexibility in network virtualization and making their infrastructure much more adaptive than today’s static provisioning [33].
New Internet business models and privacy
The networks research community has been witnessing an explosive growth in the adoption of wireless devices such as smartphones and tablets. This new fertile market has been fueled by applications and games brought through multiple markets of third party developers. These markets today rely on “App Stores” provided and controlled by device or operating system manufacturers such as Apple or Google, now recently joined by Facebook. At the heart of this trade lies a particular revenue model: provide attractive content and applications, and in return benefit from a trusted ecosystem built from a large number of users. Majority of these ecosystems revolve around targetted advertising and use of personal information. Several recent proposals have been made by the networks and social computing research community, on enabling market places for personal information [34,35].
It has been suggested that personal data is the new currency on the Internet. This highlights the urgent need for understanding privacy issues, which requires engagement with policy makers and investing in new methods to create federated marketplaces for resources and data.
Engaging all stakeholders
The deep changes we discussed create unprecedented opportunities for industry and researchers to develop new solutions that will address not only relevant operational challenges, but also potentially business-critical ones. The ossification of the Internet protocols does not mean that the Internet is not evolving. The Internet has changed enormously over the last decade, and will continue to do so, no matter what. What we observe today is a convergence of applications/content and network infrastructure that questions a model of the Internet that used to separate two stakeholders: application/content infrastructures on the one side and a dumb transport network on the other.
The fundamental changes in the Internet lead to fundamental questions about the possible directions in which the Internet might be going, not only at a technical level, but also from a business perspective. These are Societal questions, that ask for answers for the sake of Internet governance and to ensure that the infrastructure is serving the purposes of the Society as a whole, not of a few business players. Emphasis must also be placed on engagement with users as the focal point of the ecosystem, not only business stakeholders.
Active Engagement with the European Community and Beyond
Traditionally, EU projects in the networking area have not been strongly urged to engage with the public, but focus their attention on the impact for European Industry. Given the Societal relevance of the Internet in supporting the Digital Economy, we encourage that future projects have wider and more specific public engagement and community reach plans, engaging user communities, industrial bodies, the research community, policy makers and the Internet governing bodies. This approach will encourage working beyond the usual outputs in the form of periodic reports and standard workshops that do not reach the relevant audience. Re-focusing the dissemination and impact criteria during project evaluation would incentivize projects to target long-term growth and innovation in Europe. We feel that today impact and dissemination play mostly a role at satisfying short-term industrial or business use-cases, which are heavily biased by industrial partners during review process of project proposals for impact.
Lastly, we encourage the inclusion of research and development organisations in China, India, Brazil and similar developing countries which are shaping the future of the network usage trends. Indeed, we now live in a globalized world, meaning that EU project should compete with their US and Chinese counterparts, both in terms of agenda but also in terms of their reach and impact.
[1] C. Labovitz, S. Lekel-Johnson, D. McPherson, J. Oberheide, and F. Jahanian, “Internet Inter-Domain Traffic,” in Proc. of ACM SIGCOMM, 2010.
[2] K. Claffy, H. Braun, and G. Polyzos, “Traffic Characteristics of the T1 NSFNET backbone,” in Proc. of IEEE INFOCOM, 1993.
[3] K. Thompson, G. Miller, and R. Wilder, “Wide-Area Internet Traffic Patterns and Characteristics,” IEEE Network Magazine, 11(6), November/December 1997.
[4] W. Fang and L. Peterson, “Inter-AS Traffic Patterns and their Implications,” in Proc. of IEEE Global Internet Symposium, 1999.
[5] L. Subramanian, S. Agarwal, J. Rexford, and R. Katz, “Characterizing the Internet Hierarchy from Multiple Vantage Points,” in Proc. of IEEE INFOCOM, 2002.
[6] B. Krishnamurthy, C. Wills, and Y. Zhang, “On the Use and Performance of Content Distribution Networks,” in Proc. of ACM IMW, 2001.
[7] R. Krishnan, H. Madhyastha, S. Srinivasan, S. Jain, A. Krishnamurthy, T. Anderson, and J. Gao, “Moving Beyond End-to-end Path Information to Optimize CDN Performance,” in Proc. of ACM Internet Measurement Conference, 2009.
[8] T. Leighton, “Improving Performance on the Internet,” Communications of the ACM, 52(2):44–51, 2009.
[9] J. Jung, E. Sit, H. Balakrishnan, and R. Morris, “DNS Performance and the Effectiveness of Caching,” IEEE/ACM Trans. Netw., 10(5):589–603, 2002.
[10] P. Vixie, “What DNS is Not,” Commun. of the ACM, vol. 52, no. 12, 2009.
[11] B. Ager, W. Muehlbauer, G. Smaragdakis, and S. Uhlig, “Comparing DNS Resolvers in the Wild,” in Proc. of ACM Internet Measurement Conference, 2010.
[12] C. Contavalli, W. van der Gaast, S. Leach, and D. Rodden, “Client IP Information in DNS requests,” IETF draft, work in progress, draftvandergaast-edns-client-ip-00.txt, Jan 2010.
[13] “Quagga Routing Suite,” http://www.quagga.net.
[14] M. Handley, O. Hodson, and E. Kohler, “XORP: an Open Platform for Network Research,” ACM Comp. Comm. Rev., vol. 33, no. 1, 2003.
[15] J. Edwards, “Enterprises Cut Costs with Open-source Routers,” http:
//www.computerworld.com/s/article/9133851, 2009.
[16] “IP Infusion ZebOS,” http://www.ipinfusion.com/.
[17] Arista Networks, “EOS: An Extensible Operating System,” www.aristanetworks.com/en/EOS, 2009.
[18] E. Kohler, R. Morris, B. Chen, J. Jannotti, and F. Kaashoek, “The Click Modular Router,” ACM Trans. Comput. Syst., 18(3):263– 297, August 2000.
[19] N. Egi, A. Greenhalgh, M. Handley, M. Hoerdt, F. Huici, and L. Mathy, “Towards High Performance Virtual Routers on Commodity Hardware,” in Proc. of ACM CoNEXT, 2008.
[20] M. Dobrescu, N. Egi, K. Argyraki, B. Chun, K. Fall, G. Iannaccone, A. Knies, M. Manesh, and S. Ratnasamy, “RouteBricks: Exploiting Parallelism to Scale Software Routers,” in Proc. of ACM SOSP, 2009.
[21] N. McKeown, T. Anderson, H. Balakrishnan, G. Parulkar, L. Peterson, J. Rexford, S. Shenker, and J. Turner, “OpenFlow: Enabling Innovation in Campus Networks,” ACM Comp. Comm. Rev., 2008.
[22] C. Huang, A. Wang, J. Li, and K. W. Ross, “Measuring and Evaluating Large-scale CDNs,” in Proc. of ACM Internet Measurement Conference, 2008. Paper withdrawn at Microsoft request.
[23] S. Triukose, Z. Al-Qudah, and M. Rabinovich, “Content Delivery Networks: Protection or Threat?” in Proc. of ESORICS, 2009.
[24] B. Fortz and M. Thorup, “Internet Traffic Engineering by Optimizing OSPF Weights,” in Proc. of IEEE INFOCOM, 2000.
[25] B. Fortz and M. Thorup, “Optimizing OSPF/IS-IS Weights in a Changing World,” IEEE Journal in Selected Areas in Communications, 20(4):756–767, 2002.
[26] Y. Wang, Z. Wang, and L. Zhang, “Internet Traffic Engineering Without Full Mesh Overlaying,” in Proc. of IEEE INFOCOM, 2001.
[27] R. Mahajan, D. Wetherall, and T. Anderson, “Understanding BGP Misconfigurations,” in Proc. of ACM SIGCOMM, 2002.
[28] C. Labovitz, G. R. Malan, and F. Jahanian, “Internet Routing Instability,” in Proc. of ACM SIGCOMM, 1997.
[29] T. Griffin and G. Wilfong, “An Analysis of BGP Convergence Properties,” in Proc. of ACM SIGCOMM, 1999.
[30] C. Labovitz, A. Ahuja, A. Bose, and F. Jahanian, “Delayed Internet Routing Convergence,” in Proc. of ACM SIGCOMM, 2000.
[32] Ingmar Poese, Benjamin Frank, Bernhard Ager, Georgios Smaragdakis, Steve Uhlig, Anja Feldmann, "Improving Content Delivery with PaDIS," IEEE Internet Computing, 16(3):46-52, May-June 2012.
[33] J. He, R. Zhang-Shen, Y. Li, C.-Y. Lee, J. Rexford, and M. Chiang, “DaVinci: Dynamically Adaptive Virtual Networks for a Customized Internet,” in Proc. of ACM CoNEXT, 2008.
[34] Hamed Haddadi, Richard Mortier, Steven Hand, Ian Brown, Eiko Yoneki, Derek McAuley and Jon Crowcroft: “Privacy Analytics”. ACM SIGCOMM Computer Communication Review, April 2012.
[35] Christina Aperjis and Bernardo A. Huberman. A Market for Unbiased Private Data: Paying Individuals According to their Privacy Attitudes. Available at http://dx.doi.org/10.2139/ssrn.2046861, April 2012.
