Towards capturing representative AS-level Internet topologies

Computer Communications, 2011

The AS-level topology of the Internet has been quite a hot research topic in the last few years. However, only a small number of studies have been developed that give a structural interpretation of this graph. Such an interpretation is crucially important in order to test protocols and optimal routing algorithms, to design efficient networks, and for failure detection purposes. Moreover, most research does not highlight the role that IXPs have on the AS-level structure of the Internet, although their role is recognized as fundamental. The initial contribution of this study is an analysis of the most important AS-level topologies that are publicly found on the web and an analysis of the topology obtained when they are merged. We compiled structural information from this topology making considerable use of the k-core decomposition technique to delineate various particular classes of nodes. Next, we associated node properties with a reasonable modus operandi of the ASs on the Internet. The second contribution is a study of the impact that ASs connected to IXPs and BGP connections crossing IXPs have on the AS-level topology. To achieve this, we developed a procedure to gather reliable information related to IXPs and their participants. 1 The IPv4 Routed /24 AS Links Dataset, Y.

Proceedings of the SIGCOMM '20 Poster and Demo Sessions, 2020

We present a methodology to infer business relationships between ASes using routing polices stored in the Internet Routing Registries (IRR), which are a set of databases used by ASes to register their inter-domain routing policies. We show that the overall accuracy of our algorithm is comparable (95% for p2c, 92% for p2p links) to the existing algorithms, which infer AS relationships using BGP AS paths. We highlight that the IRR is a strong complementary source for better understandings of the structure, performance, dynamics, and evolution of the Internet since it is actively used by a large number of operational ASes in the Internet. CCS CONCEPTS • Networks → Routing protocols.

IEEE/ACM Transactions on Networking, 2000

Despite significant efforts to obtain an accurate picture of the Internet's connectivity structure at the level of individual autonomous systems (ASes), much has remained unknown in terms of the quality of the inferred AS maps that have been widely used by the research community. In this paper, we assess the quality of the inferred Internet maps through case studies of a sample set of ASes. These case studies allow us to establish the ground truth of connectivity between this set of ASes and their directly connected neighbors. A direct comparison between the ground truth and inferred topology maps yield insights into questions such as which parts of the actual topology are adequately captured by the inferred maps, which parts are missing and why, and what is the percentage of missing links in these parts. This information is critical in assessing, for each class of real-world networking problems, whether the use of currently inferred AS maps or proposed AS topology models is, or is not, appropriate. More importantly, our newly gained insights also point to new directions towards building realistic and economically viable Internet topology maps.

Networks and Heterogeneous Media, 2006

The Internet's layered architecture and organizational structure give rise to a number of different topologies, with the lower layers defining more physical and the higher layers more virtual/logical types of connectivity structures. These structures are very different, and successful Internet topology modeling requires annotating the nodes and edges of the corresponding graphs with information that reflects their network-intrinsic meaning. These structures also give rise to different representations of the traffic that traverses the heterogeneous Internet, and a traffic matrix is a compact and succinct description of the traffic exchanges between the nodes in a given connectivity structure. In this paper, we summarize recent advances in Internet research related to (i) inferring and modeling the router-level topologies of individual service providers (i.e., the physical connectivity structure of an ISP, where nodes are routers/switches and links represent physical connections), (ii) estimating the intra-AS traffic matrix when the AS's router-level topology and routing configuration are known, (iii) inferring and modeling the Internet's AS-level topology, and (iv) estimating the inter-AS traffic matrix. We will also discuss recent work on Internet connectivity structures that arise at the higher layers in the IP/TCP protocol stack and are more virtual and dynamic; e.g., overlay networks like the WWW graph, where nodes are web pages and edges represent existing hyperlinks, or P2P networks like Gnutella, where nodes represent peers and two peers are connected if they have an active network connection. Here, an autonomous system (AS) or autonomous domain is a group of routers and networks managed by a single organization. In turn, an Internet Service Provider (ISP) can consist of a single AS or of a group of ASes, but for simplicity, we will use the terms AS and ISP indistinguishably throughout this paper. The TCP/IP protocol stack as a whole and IP in particular are able to hide from the user much of the enormous complexity associated with controlling this diverse set of networked resources and coordinating the actions among the many competing ISPs. By providing the mechanisms necessary to knit together diverse networking technologies and ASes into a single virtual network (i.e., a network of networks, or "Internet"), they ultimately guarantee seamless connectivity and reliable communication between sending and receiving hosts, irrespective of where in the network they are.

2006

In this paper we introduce a new metric for analyzing the behavior of ASPATH values in the Border Gateway Protocol (BGP) routing protocol. We base our metric on the edit distance algorithm, an algorithm used for approximate string matching. We modify this basic algorithm by adding features that embed BGP domain knowledge. This allows us to perform meaningful comparisons of ASPATH values contained in BGP update messages. We call our modified metric ASPATH Edit Distance(AED). We illustrate the application of this metric to characterize ASPATH changes at a global scale using the example of a major Internet routing anomaly. At the other end of the spectrum we illustrate how this metric can be used to quantify and model the behavior of ASPATH values for individual Autonomous Systems. AED provides us with an important measure with which we can study the behavior of ASPATHS in the Internet. With sufficient refinement, AED can be suitably adapted and used alongside other metrics in BGP routing anomaly detection algorithms and tools.

Passive and Active Measurement, 2010

Although traceroute has the potential to discover AS links that are invisible to existing BGP monitors, it is well known that the common approach for mapping router IP address to AS number (IP2AS) based on the longest prefix matching is highly error-prone. In this paper we conduct a systematic investigation into the potential errors of the IP2AS mapping for AS topology inference. In comparing traceroutederived AS paths and BGP AS paths, we take a novel approach of identifying mismatch fragments between each path pair. We then identify the origin and cause of each mismatch with a systematic set of tests based on publicly available data sets. Our results show that about 60% of mismatches are due to IP address sharing between peering BGP routers in neighboring ASes, and only about 14% of the mismatches are caused by the presence of IXPs, siblings, or prefixes with multiple origin ASes. This result helps clarify an argument that comes from previous work regarding the major cause of errors in converting traceroute paths to AS paths. Our results also show that between 16% and 47% of AS adjacencies in two public repositories for traceroute-derived topology are false.

Technical Report, 2008

Despite significant efforts to obtain an accurate picture of structure at the level of individual autonomous systems (ASes), much remains unknown in terms of the quality of the inferred AS maps that have been widely used by the research community. Building upon our recent results reported in [16], in this paper we take a first step towards quantifying the (in) completeness of the observed AS-level connectivity as seen by the commonly-used vantage points of RouteViews and RIPE-RIS. Calling the current set of vantage points the ���public ...

Lecture Notes in Computer Science, 2011

The structure of the Internet is still unknown even though it provides services for most of the world. Its current configuration is the result of complex economic interactions developed in the last 20 years among important carriers and ISPs. Although with only some success, in the last few years some research has tried to shed light on the economic relationships established among ASes. The typical approaches have two phases: in the first, data from BGP monitors is gathered to infer the Internet AS-level topology graph, while in the second phase, algorithms are instantiated on this graph to derive economic tags for all edges between nodes (i.e. ASes). This paper provides significant findings for both steps. Specifically, regarding the second step, a small set of transit-free ASes and the lifespan of any AS paths are the input to an algorithm that we have devised which assigns an economic tag to each AS connection. The quality of inferred tags is expressed by a weight which takes into consideration the lifespan of the connection it refers to, as well as the outcome of the so called two-way validation approach. Regarding the first step the paper reports another valuable contribution targeted at identifying and cleaning the presence of fake connections induced by typos.

ACM SIGCOMM Computer Communication Review, 2005

At the inter-domain level, the Internet topology can be represented by a graph with Autonomous Systems (ASes) as nodes and AS peerings as links. This AS-level topology graph has been widely used in a variety of research efforts. Conventionally this topology graph is derived from routing tables collected by Route Views or RIPE RIS. In this work, we assemble the most complete AS-level topology by extending the conventional method along two dimensions. First, in addition to using data from RouteViews and RIPE RIS, we also collect data from many other sources, including route servers, looking glasses, and routing registries. Second, in addition to using routing tables, we also accumulate topological information from routing updates over time. The resulting topology graph on a recent day contains 44% more links and 3% more nodes than that from using RouteViews routing tables alone. Our data collection and topology generation process have been automated, and we publish the latest topology...

The Internet Protocol Journal, 2001

The rapid growth of the Internet has led to numerous changes to the underlying technologies. In the early days, host names and their corresponding IP addresses were kept in a flat text file (" HOSTS.TXT "), updated weekly by the Network Information Center at SRI International. In the mid 1980s it became clear that this method of name/ address mapping would not scale, and a new distributed lookup mechanism was designed and deployed. This new method, known as the Domain Name System (DNS), has proven successful even in the face of millions of Internet hosts. Another result of Internet growth is the potential for depletion of the IP Version 4 (IPv4) 32-bit address space. In the early 1990s, this became a matter of great focus for the Internet Engineering Task Force (IETF). The " short-term " fix for this problem was to abandon the original concept of A, B and C address classes and introduce Classless Interdomain Routing (CIDR), which consumes addresses in a much more...