There is more to IXPs than meets the eye
04 Nov 2013-Vol. 43, Iss: 5, pp 19-28
TL;DR: It is argued in this article that IXPs are all about data centers and cloud services and even SDN and mobile communication and should be of great interest to networking researchers interested in understanding the current and future Internet ecosystem.
Abstract: Internet eXchange Points (IXPs) are generally considered to be the successors of the four Network Access Points (NAPs) that were mandated as part of the decommissioning of the National Science Foundation Network (NSFNET) in 1994/95 to facilitate the transition from the NSFNET to the "public Internet" as we know it today. While this popular view does not tell the whole story behind the early beginnings of IXPs, what is true is that since around 1994, the number of operational IXPs worldwide has grown to more than 300 (as of May 2013), with the largest IXPs handling daily traffic volumes comparable to those carried by the largest Tier-1 ISPs. However, IXPs have never really attracted much attention from the networking research community. At first glance, this lack of interest seems understandable as IXPs have apparently little to do with current "hot" topic areas such as data centers and cloud services or Software Defined Networking (SDN) and mobile communication. However, we argue in this article that, in fact, IXPs are all about data centers and cloud services and even SDN and mobile communication and should be of great interest to networking researchers interested in understanding the current and future Internet ecosystem. To this end, we survey the existing but largely fragmented sources of publicly available information about IXPs to describe their basic technical and operational aspects and highlight the critical differences among the various IXPs in the different regions of the world, especially in Europe and North America. More importantly, we illustrate the important role that IXPs play in today's Internet ecosystem and discuss how IXP-driven innovation in Europe is shaping and redefining the Internet marketplace, not only in Europe but increasingly so around the world.
Citations
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28 Oct 2015
TL;DR: Measurements show that Google connects directly to networks hosting more than 60% of end-user prefixes, and that other large content providers have similar connectivity, which opens the possibility of solutions that sidestep the headache of Internet-wide deployability.
Abstract: The Internet suffers from well-known performance, reliability, and security problems. However, proposed improvements have seen little adoption due to the difficulties of Internet-wide deployment. We observe that, instead of trying to solve these problems in the general case, it may be possible to make substantial progress by focusing on solutions tailored to the paths between popular content providers and their clients, which carry a large share of Internet traffic.In this paper, we identify one property of these paths that may provide a foothold for deployable solutions: they are often very short. Our measurements show that Google connects directly to networks hosting more than 60% of end-user prefixes, and that other large content providers have similar connectivity. These direct paths open the possibility of solutions that sidestep the headache of Internet-wide deployability, and we sketch approaches one might take to improve performance and security in this setting.
109 citations
Cites background from "There is more to IXPs than meets th..."
...Services are moving to well-connected clouds; providers are building out serving infrastructure [9, 18]; and peering is on the rise [11, 37]....
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27 Apr 2018
TL;DR: In this paper, the authors study the infrastructure deployment of a content hypergiant, Netflix, and show that the combined worldwide IXP substrate is the major corner stone of its Content Delivery Network.
Abstract: The importance of IXPs to interconnect different networks and exchange traffic locally has been well studied over the last few years. However, far less is known about the role IXPs play as a platform to enable large-scale content delivery and to reach a world-wide customer base. In this paper, we study the infrastructure deployment of a content hypergiant, Netflix, and show that the combined worldwide IXP substrate is the major corner stone of its Content Delivery Network. This highlights the additional role that IXPs play in the Internet ecosystem, not just in terms of interconnection, but also allowing players such as Netflix to deliver significant amounts of traffic.
95 citations
05 Nov 2014
TL;DR: A first-of-its-kind study that correlates a detailed control plane view with a rich data plane view to reason about the different peering options available at these IXPs and how some of the major Internet players make use of them is performed.
Abstract: During the last few years, more and more of the medium-to-large Internet eXchange Points (IXP) around the world have started to operate a route server and offer its use as a free value-added service to their members. This service has greatly simplified inter-domain routing for those members and has made it easy for them to peer with possibly hundreds of networks at those IXPs from the get-go. In this paper, we report on an empirical analysis that is based on a unique collection of IXP-provided datasets from two different European IXPs that operate a route server and gave us access to a wealth of route server-specific BGP data. Both IXPs also made the traffic datasets that they routinely collect from their public switching infrastructures available to us. Using this information, we perform a first-of-its-kind study that correlates a detailed control plane view with a rich data plane view to reason about the different peering options available at these IXPs and how some of the major Internet players make use of them. In the process, we highlight the important role that the IXPs' route servers play for inter-domain routing in today's Internet and demonstrate the benefits of studying IXP peerings in a manner that is not agnostic but fully aware of traffic. We conclude with a discussion of some of the ramifications of our findings for both network researchers and operators.
78 citations
Cites background from "There is more to IXPs than meets th..."
...Especially in Europe where many IXPs operate on a not-for-profit basis [21], this observation has led to significant innovations at IXPs in the form of constantly expanding service offerings....
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...This growing importance of IXPs for the Internet peering ecosystem and the IXPs’ increasing popularity with the full spectrum of Internet players have come in full view with recent studies such as [17, 21, 25, 36]....
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TL;DR: The current CDN ecosystem and the forces that have driven its evolution are described and the different CDN architectures are outlined and considered and their relative strengths and weaknesses are outlined.
68 citations
02 Dec 2014
TL;DR: The first systematic study of remote peering is presented, an interconnection where remote networks peer via a layer-2 provider, and the results challenge the traditional reliance on layer-3 topologies in modeling the Internet economic structure.
Abstract: The trend toward more peering between networks is commonly conflated with the trend of Internet flattening, i.e., reduction in the number of intermediary organizations on Internet paths. Indeed, direct peering interconnections bypass layer-3 transit providers and make the Internet flatter. This paper studies an emerging phenomenon that separates the two trends: we present the first systematic study of remote peering, an interconnection where remote networks peer via a layer-2 provider. Our measurements reveal significant presence of remote peering at IXPs (Internet eXchange Points) worldwide. Based on ground truth traffic, we also show that remote peering has a substantial potential to offload transit traffic. Generalizing the empirical results, we analytically derive conditions for economic viability of remote peering versus transit and direct peering. Because remote-peering services are provided on layer 2, our results challenge the traditional reliance on layer-3 topologies in modeling the Internet economic structure. We also discuss broader implications of remote peering for reliability, security, accountability, and other aspects of Internet research.
64 citations
Cites background from "There is more to IXPs than meets th..."
...If a network is not co-located with the IXP already, the network can establish its IP presence at the IXP by contracting an IP transport service or extending its own IP infrastructure to reach the IXP location....
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References
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17 Aug 2014
TL;DR: The experiments demonstrate that the SDX implementation can implement representative policies for hundreds of participants who advertise full routing tables while achieving sub-second convergence in response to configuration changes and routing updates.
Abstract: BGP severely constrains how networks can deliver traffic over the Internet. Today's networks can only forward traffic based on the destination IP prefix, by selecting among routes offered by their immediate neighbors. We believe Software Defined Networking (SDN) could revolutionize wide-area traffic delivery, by offering direct control over packet-processing rules that match on multiple header fields and perform a variety of actions. Internet exchange points (IXPs) are a compelling place to start, given their central role in interconnecting many networks and their growing importance in bringing popular content closer to end users. To realize a Software Defined IXP (an "SDX"), we must create compelling applications, such as "application-specific peering"---where two networks peer only for (say) streaming video traffic. We also need new programming abstractions that allow participating networks to create and run these applications and a runtime that both behaves correctly when interacting with BGP and ensures that applications do not interfere with each other. Finally, we must ensure that the system scales, both in rule-table size and computational overhead. In this paper, we tackle these challenges and demonstrate the flexibility and scalability of our solutions through controlled and in-the-wild experiments. Our experiments demonstrate that our SDX implementation can implement representative policies for hundreds of participants who advertise full routing tables while achieving sub-second convergence in response to configuration changes and routing updates.
342 citations
"There is more to IXPs than meets th..." refers background in this paper
...In fact, if SDN can deliver on the promise expressed in [58] “to herald a new day for interdomain routing by allowing BGP’s control plane to evolve independently from the underlying switch and router hardware and bringing software control and logic to interdomain routing”, then a software defined Internet exchange that builds on the initial concept proposed in [58] may well be the future [82, 84]....
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TL;DR: In this paper, the authors examine the infrastructure that comprises the network of networks and the spatial patterns that make it possible for the Internet to evolve and adapt to the emerging twenty-first century.
Abstract: The Internet is perhaps the defining technology of the emerging twenty-first century. This article examines the infrastructure that comprises the “network of networks” and the spatial patterns that...
280 citations
13 Aug 2012
TL;DR: A first-of-its-kind and in-depth analysis of one of the largest IXPs worldwide based on nine months' worth of sFlow records collected at that IXP in 2011 suggests that these large IXPs can be viewed as a microcosm of the Internet ecosystem itself and argues for a re-assessment of the mental picture the community has about this ecosystem.
Abstract: The largest IXPs carry on a daily basis traffic volumes in the petabyte range, similar to what some of the largest global ISPs reportedly handle. This little-known fact is due to a few hundreds of member ASes exchanging traffic with one another over the IXP's infrastructure. This paper reports on a first-of-its-kind and in-depth analysis of one of the largest IXPs worldwide based on nine months' worth of sFlow records collected at that IXP in 2011.A main finding of our study is that the number of actual peering links at this single IXP exceeds the number of total AS links of the peer-peer type in the entire Internet known as of 2010! To explain such a surprisingly rich peering fabric, we examine in detail this IXP's ecosystem and highlight the diversity of networks that are members at this IXP and connect there with other member ASes for reasons that are similarly diverse, but can be partially inferred from their business types and observed traffic patterns. In the process, we investigate this IXP's traffic matrix and illustrate what its temporal and structural properties can tell us about the member ASes that generated the traffic in the first place. While our results suggest that these large IXPs can be viewed as a microcosm of the Internet ecosystem itself, they also argue for a re-assessment of the mental picture that our community has about this ecosystem.
278 citations
Additional excerpts
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TL;DR: The findings point out the need for continuously questioning the applicability and completeness of data sets at hand when establishing the generality of any particular Internet-specific observation and for assessing its (in)sensitivity to deficiencies in the measurements.
215 citations
"There is more to IXPs than meets th..." refers background in this paper
...While IXPs have occasionally featured in networking research papers (see, for example, [60, 85, 65, 56, 76, 59, 78, 63], to mention but a few), they are typically the focal point of Norton’s white papers on various aspects related to peering (e....
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TL;DR: An Internet-wide traceroute study that was specifically designed to shed light on the unknown IXP-specific peering matrices and involves targeted traceroutes from publicly available and geographically dispersed vantage points is reported on.
Abstract: Internet exchange points (IXPs) are an important ingredient of the Internet AS-level ecosystem - a logical fabric of the Internet made up of about 30,000 ASes and their mutual business relationships whose primary purpose is to control and manage the flow of traffic. Despite the IXPs' critical role in this fabric, little is known about them in terms of their peering matrices (i.e., who peers with whom at which IXP) and corresponding traffic matrices (i.e., how much traffic do the different ASes that peer at an IXP exchange with one another). In this paper, we report on an Internet-wide traceroute study that was specifically designed to shed light on the unknown IXP-specific peering matrices and involves targeted traceroutes from publicly available and geographically dispersed vantage points. Based on our method, we were able to discover and validate the existence of about 44K IXP-specific peering links - nearly 18K more links than were previously known. In the process, we also classified all known IXPs depending on the type of information required to detect them. Moreover, in view of the currently used inferred AS-level maps of the Internet that are known to miss a significant portion of the actual AS relationships of the peer-to-peer type, our study provides a new method for augmenting these maps with IXP-related peering links in a systematic and informed manner.
200 citations