812 research outputs found
Beyond Counting: New Perspectives on the Active IPv4 Address Space
In this study, we report on techniques and analyses that enable us to capture
Internet-wide activity at individual IP address-level granularity by relying on
server logs of a large commercial content delivery network (CDN) that serves
close to 3 trillion HTTP requests on a daily basis. Across the whole of 2015,
these logs recorded client activity involving 1.2 billion unique IPv4
addresses, the highest ever measured, in agreement with recent estimates.
Monthly client IPv4 address counts showed constant growth for years prior, but
since 2014, the IPv4 count has stagnated while IPv6 counts have grown. Thus, it
seems we have entered an era marked by increased complexity, one in which the
sole enumeration of active IPv4 addresses is of little use to characterize
recent growth of the Internet as a whole.
With this observation in mind, we consider new points of view in the study of
global IPv4 address activity. Our analysis shows significant churn in active
IPv4 addresses: the set of active IPv4 addresses varies by as much as 25% over
the course of a year. Second, by looking across the active addresses in a
prefix, we are able to identify and attribute activity patterns to network
restructurings, user behaviors, and, in particular, various address assignment
practices. Third, by combining spatio-temporal measures of address utilization
with measures of traffic volume, and sampling-based estimates of relative host
counts, we present novel perspectives on worldwide IPv4 address activity,
including empirical observation of under-utilization in some areas, and
complete utilization, or exhaustion, in others.Comment: in Proceedings of ACM IMC 201
Discovering the IPv6 Network Periphery
We consider the problem of discovering the IPv6 network periphery, i.e., the
last hop router connecting endhosts in the IPv6 Internet. Finding the IPv6
periphery using active probing is challenging due to the IPv6 address space
size, wide variety of provider addressing and subnetting schemes, and
incomplete topology traces. As such, existing topology mapping systems can miss
the large footprint of the IPv6 periphery, disadvantaging applications ranging
from IPv6 census studies to geolocation and network resilience. We introduce
"edgy," an approach to explicitly discover the IPv6 network periphery, and use
it to find >~64M IPv6 periphery router addresses and >~87M links to these last
hops -- several orders of magnitude more than in currently available IPv6
topologies. Further, only 0.2% of edgy's discovered addresses are known to
existing IPv6 hitlists
Wireless Multi Hop Access Networks and Protocols
As more and more applications and services in our society now depend on the Internet, it is important that dynamically deployed wireless multi hop networks are able to gain access to the Internet and other infrastructure networks and services. This thesis proposes and evaluates solutions for providing multi hop Internet Access. It investigates how ad hoc networks can be combined with wireless and mesh networks in order to create wireless multi hop access networks. When several access points to the Internet are available, and the mobile node roams to a new access point, the node has to make a decision when and how to change its point of attachment. The thesis describes how to consider the rapid fluctuations of the wireless medium, how to handle the fact that other nodes on the path to the access point are also mobile which results in frequent link and route breaks, and the impact the change of attachment has on already existing connections. Medium access and routing protocols have been developed that consider both the long term and the short term variations of a mobile wireless network. The long term variations consider the fact that as nodes are mobile, links will frequently break and new links appear and thus the network topology map is constantly redrawn. The short term variations consider the rapid fluctuations of the wireless channel caused by mobility and multi path propagation deviations. In order to achieve diversity forwarding, protocols are presented which consider the network topology and the state of the wireless channel when decisions about forwarding need to be made. The medium access protocols are able to perform multi dimensional fast link adaptation on a per packet level with forwarding considerations. This i ncludes power, rate, code and channel adaptation. This will enable the type of performance improvements that are of significant importance for the success of multi hop wireless networks
On Compact Routing for the Internet
While there exist compact routing schemes designed for grids, trees, and
Internet-like topologies that offer routing tables of sizes that scale
logarithmically with the network size, we demonstrate in this paper that in
view of recent results in compact routing research, such logarithmic scaling on
Internet-like topologies is fundamentally impossible in the presence of
topology dynamics or topology-independent (flat) addressing. We use analytic
arguments to show that the number of routing control messages per topology
change cannot scale better than linearly on Internet-like topologies. We also
employ simulations to confirm that logarithmic routing table size scaling gets
broken by topology-independent addressing, a cornerstone of popular
locator-identifier split proposals aiming at improving routing scaling in the
presence of network topology dynamics or host mobility. These pessimistic
findings lead us to the conclusion that a fundamental re-examination of
assumptions behind routing models and abstractions is needed in order to find a
routing architecture that would be able to scale ``indefinitely.''Comment: This is a significantly revised, journal version of cs/050802
Guifi.net: characterization, data collection and selfmanagement of community
In this project, we are going to present an E2E (end to end) solution for the principal problems that normally impact the community networks and especially Guifinet. To introduce our solution, we were investigating how the Guifinet works internally (its network hierarchy, equipment used, IP configuration and also its financial system) and also how wireless technology works and their limitations. Once we analysed and detected all the potential issues, we performed a routing performance and QoS (quality or service) simulation in order to test two experimental protocol called BATMAN and OLSR to find the most suitable routing protocol for our approach. And finally, we presented our new Guifinet network concept basing in MPLS over OLSR
Pervasive service discovery in low-power and lossy networks
Pervasive Service Discovery (SD) in Low-power and Lossy Networks (LLNs) is expected to play a major role in realising the Internet of Things (IoT) vision. Such a vision aims to expand the current Internet to interconnect billions of miniature smart objects that sense and act on our surroundings in a way that will revolutionise the future. The pervasiveness and heterogeneity of such low-power devices requires robust, automatic, interoperable and scalable deployment and operability solutions. At the same time, the limitations of such constrained devices impose strict challenges regarding complexity, energy consumption, time-efficiency and mobility.
This research contributes new lightweight solutions to facilitate automatic deployment and operability of LLNs. It mainly tackles the aforementioned challenges through the proposition of novel component-based, automatic and efficient SD solutions that ensure extensibility and adaptability to various LLN environments. Building upon such architecture, a first fully-distributed, hybrid pushpull SD solution dubbed EADP (Extensible Adaptable Discovery Protocol) is proposed based on the well-known Trickle algorithm. Motivated by EADPs’ achievements, new methods to optimise Trickle are introduced. Such methods allow Trickle to encompass a wide range of algorithms and extend its usage to new application domains. One of the new applications is concretized in the TrickleSD protocol aiming to build automatic, reliable, scalable, and time-efficient SD. To optimise the energy efficiency of TrickleSD, two mechanisms improving broadcast communication in LLNs are proposed. Finally, interoperable standards-based SD in the IoT is demonstrated, and methods combining zero-configuration operations with infrastructure-based solutions are proposed.
Experimental evaluations of the above contributions reveal that it is possible to achieve automatic, cost-effective, time-efficient, lightweight, and interoperable SD in LLNs. These achievements open novel perspectives for zero-configuration capabilities in the IoT and promise to bring the ‘things’ to all people everywhere
Clusters in the Expanse: Understanding and Unbiasing IPv6 Hitlists
Network measurements are an important tool in understanding the Internet. Due
to the expanse of the IPv6 address space, exhaustive scans as in IPv4 are not
possible for IPv6. In recent years, several studies have proposed the use of
target lists of IPv6 addresses, called IPv6 hitlists.
In this paper, we show that addresses in IPv6 hitlists are heavily clustered.
We present novel techniques that allow IPv6 hitlists to be pushed from quantity
to quality. We perform a longitudinal active measurement study over 6 months,
targeting more than 50 M addresses. We develop a rigorous method to detect
aliased prefixes, which identifies 1.5 % of our prefixes as aliased, pertaining
to about half of our target addresses. Using entropy clustering, we group the
entire hitlist into just 6 distinct addressing schemes. Furthermore, we perform
client measurements by leveraging crowdsourcing.
To encourage reproducibility in network measurement research and to serve as
a starting point for future IPv6 studies, we publish source code, analysis
tools, and data.Comment: See https://ipv6hitlist.github.io for daily IPv6 hitlists, historical
data, and additional analyse
Comparing TCP-IPv4TCP-IPv6 network performance
"December 2013.""A Thesis Presented to the Faculty of the Graduate School at the University of Missouri--Columbia In Partial Fulfillment of the Requirements for the Degree Master of Science."Thesis advisor: Dr. Gordon K. Springer.The Internet Protocol version 4 (IPv4) has been the backbone of the Internet since its inception. The growth and success of the Internet has accelerated the consumption of the IPv4 address space and hence its exhaustion is predicted very soon. Despite the use of multiple hidden and private networks to keep things going, a newer version of the protocol, Internet Protocol version 6 (IPv6), is proposed to solve this issue along with many other improvements as part of a better, newer design. For smoother transition and given the decentralized nature of the Internet, both of the protocol stacks, namely IPv4 and IPv6, are expected to be supported by the hosts and hence co-exist for a period of time. Many application programs, especially those involved in large data transfers, currently use the TCP/IP protocol suite. However, there have not been many attempts to leverage the existence of both Internet Protocol versions over a TCP connection. This thesis, through a prototype, is an attempt to improve the network utilization by using either an IPv4 or an IPv6 protocol for a TCP connection based on end-to-end measured performance between two hosts. A measurement tool, named netaware, is developed as part of this thesis to measure the end-to-end network performance for both IPv4 and IPv6 protocols within a single tool. The tool measures two performance parameters, namely the bandwidth and the latency in a multi-threaded environment. The tool utilizes a simple middleware application, also built as part of this thesis, to create and use socket connections for interprocess communication across the network between the two hosts. The middleware application is used as an intermediate level application to take care of creating IPv4 or IPv6 connections between the hosts, needed to transmit measurement and control data while measuring the performance parameters. The use of middleware application facilitates the construction of network applications by having an application developer to deal with minimal code to use either IP protocIncludes bibliographical references (pages 188-190)
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