233 research outputs found
On the Tomography of Networks and Multicast Trees
In this paper we model the tomography of scale free networks by studying the
structure of layers around an arbitrary network node. We find, both
analytically and empirically, that the distance distribution of all nodes from
a specific network node consists of two regimes. The first is characterized by
rapid growth, and the second decays exponentially. We also show that the nodes
degree distribution at each layer is a power law with an exponential cut-off.
We obtain similar results for the layers surrounding the root of multicast
trees cut from such networks, as well as the Internet. All of our results were
obtained both analytically and on empirical Interenet data
Shortcuts through Colocation Facilities
Network overlays, running on top of the existing Internet substrate, are of
perennial value to Internet end-users in the context of, e.g., real-time
applications. Such overlays can employ traffic relays to yield path latencies
lower than the direct paths, a phenomenon known as Triangle Inequality
Violation (TIV). Past studies identify the opportunities of reducing latency
using TIVs. However, they do not investigate the gains of strategically
selecting relays in Colocation Facilities (Colos). In this work, we answer the
following questions: (i) how Colo-hosted relays compare with other relays as
well as with the direct Internet, in terms of latency (RTT) reductions; (ii)
what are the best locations for placing the relays to yield these reductions.
To this end, we conduct a large-scale one-month measurement of inter-domain
paths between RIPE Atlas (RA) nodes as endpoints, located at eyeball networks.
We employ as relays Planetlab nodes, other RA nodes, and machines in Colos. We
examine the RTTs of the overlay paths obtained via the selected relays, as well
as the direct paths. We find that Colo-based relays perform the best and can
achieve latency reductions against direct paths, ranging from a few to 100s of
milliseconds, in 76% of the total cases; 75% (58% of total cases) of these
reductions require only 10 relays in 6 large Colos.Comment: In Proceedings of the ACM Internet Measurement Conference (IMC '17),
London, GB, 201
Quantifying the Effects of Circuitous Routes on the Latency of Intra-Africa Internet Traffic: A Study of Research and Education Networks
Despite an increase in the number of Internet eXchange Points (IXP) in Africa, as well as proliferation of submarine and terrestrial fibre optic cable systems, the level of peering among Africa’s Internet service providers remains low. Using active network measurements, this work characterizes the level of interconnectivity and peering among Africa’s National Research and Education Networks (NRENs),and examines the performance of traffic exchange in terms of latencies. This paper shows that over 75% of Africa’s inter-university traffic follows circuitous inter-continental routes, and is characterised by latencies that are more than double those of traffic exchanged within the continent
Tracking Middleboxes in the Mobile World with TraceboxAndroid
peer reviewedMiddleboxes are largely deployed over cellular networks. It is known that they might disrupt network performance, expose users to security issues, and harm protocols deployability. Further, hardly any network measurements tools for smartphones are able to infer middlebox behaviors, specially if one cannot control both ends of a path. In this paper, we present TraceboxAndroid a proof-of-concept measurement application for Android mobile devices implementing the tracebox algorithm. It aims at diagnosing middlebox-impaired paths by detecting and locating rewriting middleboxes. We analyze a dataset sample to highlight the range of opportunities offered by TraceboxAndroid. We show that TraceboxAndroid can be useful for mobile users as well as for the research community
MEDUSA - New Model of Internet Topology Using k-shell Decomposition
The k-shell decomposition of a random graph provides a different and more
insightful separation of the roles of the different nodes in such a graph than
does the usual analysis in terms of node degrees. We develop this approach in
order to analyze the Internet's structure at a coarse level, that of the
"Autonomous Systems" or ASes, the subnetworks out of which the Internet is
assembled. We employ new data from DIMES (see http://www.netdimes.org), a
distributed agent-based mapping effort which at present has attracted over 3800
volunteers running more than 7300 DIMES clients in over 85 countries. We
combine this data with the AS graph information available from the RouteViews
project at Univ. Oregon, and have obtained an Internet map with far more detail
than any previous effort.
The data suggests a new picture of the AS-graph structure, which
distinguishes a relatively large, redundantly connected core of nearly 100 ASes
and two components that flow data in and out from this core. One component is
fractally interconnected through peer links; the second makes direct
connections to the core only. The model which results has superficial
similarities with and important differences from the "Jellyfish" structure
proposed by Tauro et al., so we call it a "Medusa." We plan to use this picture
as a framework for measuring and extrapolating changes in the Internet's
physical structure. Our k-shell analysis may also be relevant for estimating
the function of nodes in the "scale-free" graphs extracted from other
naturally-occurring processes.Comment: 24 pages, 17 figure
Sustaining the Internet with Hyperbolic Mapping
The Internet infrastructure is severely stressed. Rapidly growing overheads
associated with the primary function of the Internet---routing information
packets between any two computers in the world---cause concerns among Internet
experts that the existing Internet routing architecture may not sustain even
another decade. Here we present a method to map the Internet to a hyperbolic
space. Guided with the constructed map, which we release with this paper,
Internet routing exhibits scaling properties close to theoretically best
possible, thus resolving serious scaling limitations that the Internet faces
today. Besides this immediate practical viability, our network mapping method
can provide a different perspective on the community structure in complex
networks
The Large Scale Curvature of Networks
Understanding key structural properties of large scale networks are crucial
for analyzing and optimizing their performance, and improving their reliability
and security. Here we show that these networks possess a previously unnoticed
feature, global curvature, which we argue has a major impact on core
congestion: the load at the core of a network with N nodes scales as N^2 as
compared to N^1.5 for a flat network. We substantiate this claim through
analysis of a collection of real data networks across the globe as measured and
documented by previous researchers.Comment: 4 pages, 5 figure
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