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Obscure Giants: Detecting the Provider-Free ASes
Get PDFInternet routing depends on economic relationships between ASes (Autonomous Systems). Despite extensive prior research of these relationships, their characterization remains imprecise. In this paper, we focus on provider-free ASes that reach the entire Internet without paying anyone for the traffic delivery. While the ground truth about PFS (set of the provider-free ASes) lies outside the public domain, we use trustworthy non-verifiable sources as a baseline for result validation.
Straightforward extraction of PFS from public datasets of inter-AS economic relationships yields poor results. Then, we develop a more sophisticated Temporal Cone (TC) algorithm that relies on topological statistics (customer cones of ASes) and exploits the temporal diversity of the datasets. Our evaluation shows that the TC algorithm infers PFS from the same public datasets with a significantly higher accuracy. We also assess the sensitivity of the TC algorithm to its parameters.Institute IMDEA Networkspu
Security analysis of wireless mesh backhauls for mobile networks
Get PDFRadio links are used to provide backhaul connectivity for base stations of mobile networks, in cases in which cable-based alternatives are not available and cannot be deployed in an economic or timely manner. While such wireless backhauls have been predominantly used in redundant tree and ring topologies in the past, mobile network operators have become increasingly interested in meshed topologies for carrier-grade wireless backhauls. However, wireless mesh backhauls are potentially more
susceptible to security vulnerabilities, given that radio links are more exposed to tampering and given their higher system complexity. This article extends prior security threat analyses of 3rd generation mobile network architectures for the case of wireless mesh backhauls. It presents a description of the security model for the
considered architecture and provides a list of the basic assumptions, security objectives, assets to be protected and actors of the analysis. On this foundation, potential security threats are analyzed and discussed and then assessed for their corresponding risk. The result of this risk assessment is then used to define a set of security requirements. Finally, we give some recommendations for wireless mesh backhaul designs and implementations following these requirements.TRUEpu
The Tragedy of the Internet Routing Commons
Get PDFOver the last years, the research community has
been deeply concerned about the scalability issues that the
Internet routing is facing. In this paper we study the economic
incentives for the Global Routing Table (GRT) explosive growth
by considering a commons model in which the GRT is a public
resource. In particular, we analyze the motivations the Autonomous Systems (ASes) have for deaggregating their assigned
address blocks. We evaluate the efficiency of the global routing
system, the properties of the game equilibria and we examine its
relation to the optimal social welfare point of the considered game
setup. We prove that the GRT, just like any common natural
resource, “remorselessly generates tragedy”, following Hardin’s
game theoretic analysis on the tragedy of the commons. Finally,
we introduce in the model a payment mechanism that aims to
avoid the tragedy of the Internet routing commons.TRUEpu
A hybrid MIPv6 and PMIPv6 distributed mobility management: The MEDIEVAL approach
Get PDFVideo is a major challenge for the future mobile Internet as it is foreseen to account for close to 64% percent of consumer mobile traffic by 2013. However, the current Internet, and in particular the mobile Internet, was not designed with video requirements in mind and, as a consequence, its architecture is very inefficient when handling this type of traffic. This paper presents a novel mobility architecture inspired by the Distributed Mobility Management paradigm, capable of coping with the future video traffic demands, in a distributed and more scalable way. In the proposed solution, mobility support services are spread among several nodes at the edge of the network, thus realizing a flatter architecture and pushing services closer to the terminals. Our approach overcomes some of the major limitations of centralized IP mobility management solutions, by extending existing standard protocols.TRUEpu
Brief Announcement: Unbounded Contention Resolution in Multiple-Access Channels
No full textA frequent problem in settings where a unique resource must be shared among users is how to resolve the contention that arises when all of them must use it, but the resource allows only for one user each time. The application of efficient solutions for this problem spans a myriad of settings such as radio communication networks or databases. For the case where the number of users is unknown, recent work has yielded fruitful results for local area networks and radio networks, although either a (possibly loose) upper bound on the number of users needs to be known [7], or the solution is suboptimal [2], or it is only implicit [11] or embedded [6] in other problems, with bounds proved only asymptotically. In this paper, under the assumption that collision detection or information on the number of contenders is not available, we present a novel protocol for contention resolution in radio networks, and we recreate a protocol previously used for other problems [11, 6], tailoring the constants for our needs. In contrast with previous work, both protocols are proved to be optimal up to a small constant factor and with high probability for big enough number of contenders. Additionally, the protocols are evaluated and contrasted with the previous work by extensive simulations. The evaluation shows that the complexity bounds obtained by the analysis are rather tight, and that both protocols proposed have small and predictable complexity for many system sizes (unlike previous proposals).TRUEpu
Backhaul design and controller placement for cooperative mobile access networks
Get PDFExploiting base station cooperation in wireless mobile access networks leads to benefits in wireless transmission
capacity, inter-cell interference management, and cell edge user
experience. The clustering of cooperative Base Station (BS) sets,
necessary for achieving the desired wireless performance, poses
several challenges in the backhaul architecture design. This paper
addresses the problem of placing and connecting controller/
processing nodes within the backhaul infrastructure, which
coordinate and/or process signals of cooperating base stations.
We formulated a Mixed Integer Linear Programm (MILP) for
this problem and a heuristic algorithm that approximates the
optimal solution. While the heuristic’s solution quality is close
to the optimum, the runtime and memory requirements are
multiple orders of magnitude lower compared to solving the
MILP. This advantage allows to use the proposed heuristic either
for backhaul/core network pre-planning or for on-the-fly network
reconfiguration during ongoing mobile network operationTRUEpu
Towards a Collision-Free WLAN: Dynamic Parameter Adjustment in CSMA/E2CA
Get PDFCarrier Sense Multiple Access with Enhanced Collision Avoidance (CSMA/ECA) is a distributed MAC protocol that allows collision-free access to the medium in WLANs.
The only difference between CSMA/ECA and the well-known
CSMA/CA is that the former uses a deterministic backoff after successful transmissions. Collision-free operation is reached after a transient state during which some collisions may occur. This article shows that the duration of the transient state can be shortened by appropriately setting the contention parameters. Standard absorbing Markov Chain theory is used to describe the behaviour of the system in the transient state and to predict the expected number of slots to reach the collision-free operation. The article also introduces CSMA/E2CA, in which a deterministic backoff is used two consecutive times after a successful transmission. CSMA/E2CA converges quicker to collision-free operation and delivers higher performance than CSMA/ECA, specially in harsh wireless scenarios with high frame error rates. The last part of the article addresses scenarios with a large number of contenders. We suggest dynamic parameter adjustment techniques to accommodate a varying (and potentially high) number of contenders. The effectiveness of these adjustments in
preventing collisions is validated by means of simulation.TRUEpu
Stateful NAT64: Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers RFC 6146
Get PDFStateful NAT64 is a mechanism developed within the BEHAVE working group to allow IPv6 clients to connect to IPv4 servers through a translation device (the NAT64) with help from a modified DNS server (the DNS64). Stateful NAT64 is based on stateless NAT64 with several modifications. draft-van-beijnum-behave-frag64 and the NAT64 fragmentation presentation were meant to promote further discussion on how to handle the translation of fragmented packets in stateful and stateless NAT64s. These works were published as RFCs in April 2011.This document describes stateful NAT64 translation, which allows IPv6-only clients to contact IPv4 servers using unicast UDP, TCP, or ICMP. One or more public IPv4 addresses assigned to a NAT64 translator are shared among several IPv6-only clients. When stateful NAT64 is used in conjunction with DNS64, no changes are usually required in the IPv6 client or the IPv4 server.Internet Engineering Task Force (IETF)pu