=Paper= {{Paper |id=Vol-1950/paper12 |storemode=property |title=Can we break the Internet?: A Robustness Analysis of the Internet Exchange Points (IXP) Network Graph. |pdfUrl=https://ceur-ws.org/Vol-1950/paper12.pdf |volume=Vol-1950 |authors=Alexandra Ibarra,Javier Bustos }} ==Can we break the Internet?: A Robustness Analysis of the Internet Exchange Points (IXP) Network Graph.== https://ceur-ws.org/Vol-1950/paper12.pdf
        Can we break the Internet?: A Robustness Analysis of the
            Internet Exchange Points (IXP) Network Graph.

                      Alexandra Ibarra                                               Javier Bustos-Jiménez
            NIC Labs, Universidad de Chile, Chile                             NIC Labs, Universidad de Chile, Chile
                   ale@niclabs.cl                                                  jbustos@niclabs.cl



                                                                                precision, and having limited CPU resources,
                                                                                the best strategy is to select the nodes with
                           Abstract                                             higher degree.

     Internet peering is the contract between
                                                                          1     Introduction
     two autonomous systems (AS) that agree to
     exchange traffic and traffic routes through                          Internet peering is the contract between two
     a physical link, it is a multi-tier hierarchy                        autonomous systems (AS) that agree to exchange
     where the first tier (of about 10-20 nodes)                          traffic and traffic routes through a physical link.
     are connected with a clique of peering links,                        The authors of [DD10] state that “The core of the
     second tier are customers of the first, and                          Internet is a multi-tier hierarchy of Transit Providers
     residential and small business access are in                         (TPs). About 10-20 tier-1 TPs, present in many
     the third tier. Therefore, it is natural to think                    geographical regions, are connected with a clique of
     that the peering exchange network (IXP)                              peering links. Regional (tier-2) ISPs are customers
     can be seen as the backbone of the Internet                          of tier-1 TPs. Residential and small business access
     itself. Then, it is very important to study and                      (tier-3) providers are typically customers of tier-2
     analyze its robustness.                                              TPs”. Therefore, it is natural to think that the peering
                                                                          network exchange network (IXP) can be seen as the
     In this work we will study IXP network
                                                                          backbone of the Internet itself.
     robustness under targeted attacks. Choosing
     the “right” node to disconnect under a greedy                           Since their correct functioning requires that the
     strategy, we will compare how much damage                            network is properly connected, it is of great
     is produced by that node disconnection                               importance to study their ability to resist failures
     and we will compare how fast we can                                  (either unintentional or targeted attacks). This ability
     decouple the IXP network using the following                         is called robustness.
     strategies: selecting the node with the higher                          We consider that an “adversary” should plan a
     degree, with higher betweenness centrality,                          greedy strategy aiming to maximize the damage with
     the higher degree in a 2-core network, and the                       minimum number of strikes. Thus, in this article
     node with higher collective influence.                               we discuss the performance of attacks based on
                                                                          the node betweenness centrality metric [BMSBJ12]
     Our work shows that the best algorithm                               over the Internet Backbone (the network formed
     for limited “strikes” in a targeted attack is                        by Internet exchange points, IXP), also comparing
     selecting the node by higher betweenness.                            the targeted attack performance against the optimal
     However, if a quick attack as important as                           network decoupling algorithm MinSum [BDSZ16].
The authors declare that there is no conflict of interest regarding
                                                                             The article is organized as follows: next section
the publication of this paper. Copyright c by the paper’s authors.        presents related work, followed by the methodology
Copying permitted for private and academic purposes.                      for collecting data and creating the IXP network




                                                                      1
(Section 3), and the analysis of IXP network as a
graph (Section 4). Conclusions are presented in
Section 5.

2   Related work
The idea to consider an IXP-based network as “the
Internet backbone” is not new; It has previously
been used as part of the “internet core” to study the
inter-AS traffic patterns and an evolution of provider
peering strategies [LIJM+ 11], to optimize the content
delivery from Google via direct paths [CSR+ 15] and
the Internet Backbone Market [BFBS05].
   To study the robustness of a network, its evolution
against failure must be analyzed. On real–world
situations, networks may confront random failures as
well as targeted attacks. For the latter, two main
categories of attacking strategies have been defined:
simultaneous and sequential attacks [HKYH02a].
Simultaneous attacks choose a set of nodes and                            Figure 1: IXP Peering Graph
remove them all at once while sequential attacks              nodes are sorted by degree at the first iteration and
choose a node to remove and given the impact of               in the latter betweenness centrality are recalculated
this removal it chooses another node, proceeding              after each disconnection. It is widely accepted to use
iteratively.                                                  those metric, because it reflects the importance of an
   On [Est06] it was found that targeted attack               node in the network [IKSW13]. Also, attack strategies
can be more effective when they are directed to               are compared by means of the Unique Robustness
bottlenecks rather than hubs. On [BRSBJ15] authors            Measure (R-index) [SMA+ 11], defined as:
present partial values of R-index while nodes are
disconnected, showing the importance of a well                                       1 X
                                                                                         N
chosen robustness metric for performing the attacks.                           R=        s(Q),                    (1)
                                                                                     N
   For a better understanding of network attacks and                                    Q=1
strategies, see [HKYH02b, MR06, RW10, SSYS10].
                                                              where N is the number of nodes in the network and
3   Building the Internet backbone graph                      s(Q) is the fraction of nodes in the largest connected
                                                              component after disconnecting nodes using a given
From peeringdb.com we collected the                           strategy. The higher the R-index, the better in terms
autonomous systems (AS) from every Internet                   of robustness.
Exchange Point (IXP) and defined them as graph                   In order to use more modern metrics, we compared
nodes, where there is an edge between any pair of             the performance of both previous metrics against
nodes if and only if there is a physical connection           CoreHD [ZZZ16] and Collective Influence (CI)
(e.g.: fiber) between them. Figure 1 shows the                [MMB+ 16] algorithms. CoreHD is based on the idea
resulting Graph, which has 786 nodes and 20, 422              that, in a power-law network, there is a high number of
edges.                                                        nodes with degree 1 that will not contribute a network
                                                              dismantling, thus first the 2-Core (nodes with degree
4   Network Analysis                                          ≥ 2 ) is built and then the node with higher degree is
In our targeted attack, we start testing a sequential         removed.
attack on our IXP network with two well known                    Collective Influence is based on the idea of
metrics: degree and betweenness centrality. At each           finding the minimal set of maximal influencers
strike, the next node to disconnect was the one with          in a network aiming to remove such set, more
the highest metric value. Notice that in the former the       precisely: “the most influential nodes in a complex




                                                          2
network form the minimal set whose removal would               5   Conclusions and Future Work
dismantle the network in many disconnected and
                                                               In this work we have presented how robust the Internet
non-extensive components” [MMB+ 16]. Following
                                                               backbone (the peering AS network) would be if an
the recommendations of [BDSZ16] at each iteration
                                                               adversary can choose wisely which AS node link
the node with highest CI2 value (calculating CI for
                                                               will aisle (or if it is DDoS-ed, or if a very unlucky
each node using a radius of 2) is removed.
                                                               accident happens). Following the recommendations,
                                                               the chosen one would be the node with a higher metric
                                                               value such as degree, betweenness, or collective
                                                               influence.
                                                                  Our work has shown that the best algorithm for
                                                               limited “strikes” in a targeted attack is selecting the
                                                               node with higher betweenness. However, if a quick
                                                               attack is important as precision, and having limited
                                                               CPU resources, the best strategy is to select the nodes
                                                               with the higher degree.
                                                                  As future work we plan to apply similar studies to
                                                               other Internet infrastructures, such as country-based
                                                               fiber interconnection, submarine Internet cables,
Figure 2: Largest component size. In the plot x-axis           etc. Also, we plan to improve the metrics for
is the iteration, and R-index is the area below curves.        robustness reflecting both the infrastructure and the
                                                               user perception.
    Plot in Figure 2 gave an idea for the best algorithm
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