2,300 research outputs found
Temporal and Spatial Classification of Active IPv6 Addresses
There is striking volume of World-Wide Web activity on IPv6 today. In early
2015, one large Content Distribution Network handles 50 billion IPv6 requests
per day from hundreds of millions of IPv6 client addresses; billions of unique
client addresses are observed per month. Address counts, however, obscure the
number of hosts with IPv6 connectivity to the global Internet. There are
numerous address assignment and subnetting options in use; privacy addresses
and dynamic subnet pools significantly inflate the number of active IPv6
addresses. As the IPv6 address space is vast, it is infeasible to
comprehensively probe every possible unicast IPv6 address. Thus, to survey the
characteristics of IPv6 addressing, we perform a year-long passive measurement
study, analyzing the IPv6 addresses gleaned from activity logs for all clients
accessing a global CDN.
The goal of our work is to develop flexible classification and measurement
methods for IPv6, motivated by the fact that its addresses are not merely more
numerous; they are different in kind. We introduce the notion of classifying
addresses and prefixes in two ways: (1) temporally, according to their
instances of activity to discern which addresses can be considered stable; (2)
spatially, according to the density or sparsity of aggregates in which active
addresses reside. We present measurement and classification results numerically
and visually that: provide details on IPv6 address use and structure in global
operation across the past year; establish the efficacy of our classification
methods; and demonstrate that such classification can clarify dimensions of the
Internet that otherwise appear quite blurred by current IPv6 addressing
practices
An Internet Heartbeat
Obtaining sound inferences over remote networks via active or passive
measurements is difficult. Active measurement campaigns face challenges of
load, coverage, and visibility. Passive measurements require a privileged
vantage point. Even networks under our own control too often remain poorly
understood and hard to diagnose. As a step toward the democratization of
Internet measurement, we consider the inferential power possible were the
network to include a constant and predictable stream of dedicated lightweight
measurement traffic. We posit an Internet "heartbeat," which nodes periodically
send to random destinations, and show how aggregating heartbeats facilitates
introspection into parts of the network that are today generally obtuse. We
explore the design space of an Internet heartbeat, potential use cases,
incentives, and paths to deployment
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
Supporting Cyber-Physical Systems with Wireless Sensor Networks: An Outlook of Software and Services
Sensing, communication, computation and control technologies are the essential building blocks of a cyber-physical system (CPS). Wireless sensor networks (WSNs) are a way to support CPS as they provide fine-grained spatial-temporal sensing, communication and computation at a low premium of cost and power. In this article, we explore the fundamental concepts guiding the design and implementation of WSNs. We report the latest developments in WSN software and services for meeting existing requirements and newer demands; particularly in the areas of: operating system, simulator and emulator, programming abstraction, virtualization, IP-based communication and security, time and location, and network monitoring and management. We also reflect on the ongoing
efforts in providing dependable assurances for WSN-driven CPS. Finally, we report on its applicability with a case-study on smart buildings
A Multi-perspective Analysis of Carrier-Grade NAT Deployment
As ISPs face IPv4 address scarcity they increasingly turn to network address
translation (NAT) to accommodate the address needs of their customers.
Recently, ISPs have moved beyond employing NATs only directly at individual
customers and instead begun deploying Carrier-Grade NATs (CGNs) to apply
address translation to many independent and disparate endpoints spanning
physical locations, a phenomenon that so far has received little in the way of
empirical assessment. In this work we present a broad and systematic study of
the deployment and behavior of these middleboxes. We develop a methodology to
detect the existence of hosts behind CGNs by extracting non-routable IP
addresses from peer lists we obtain by crawling the BitTorrent DHT. We
complement this approach with improvements to our Netalyzr troubleshooting
service, enabling us to determine a range of indicators of CGN presence as well
as detailed insights into key properties of CGNs. Combining the two data
sources we illustrate the scope of CGN deployment on today's Internet, and
report on characteristics of commonly deployed CGNs and their effect on end
users
FAIR: Forwarding Accountability for Internet Reputability
This paper presents FAIR, a forwarding accountability mechanism that
incentivizes ISPs to apply stricter security policies to their customers. The
Autonomous System (AS) of the receiver specifies a traffic profile that the
sender AS must adhere to. Transit ASes on the path mark packets. In case of
traffic profile violations, the marked packets are used as a proof of
misbehavior.
FAIR introduces low bandwidth overhead and requires no per-packet and no
per-flow state for forwarding. We describe integration with IP and demonstrate
a software switch running on commodity hardware that can switch packets at a
line rate of 120 Gbps, and can forward 140M minimum-sized packets per second,
limited by the hardware I/O subsystem.
Moreover, this paper proposes a "suspicious bit" for packet headers - an
application that builds on top of FAIR's proofs of misbehavior and flags
packets to warn other entities in the network.Comment: 16 pages, 12 figure
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IPv6 Diffusion Milestones: Assessing the Quantity and Quality of Adoption
There are currently two versions of Internet Protocol (IP) in use today, IP version 4 (IPv4) and IP version 6 (IPv6). The original version, IPv4, was standardized in the early 1980s as part of the Defense Advanced Research Project Agency Internet program and became the official Internet protocol in 1983 (Kleinrock, 2010). IPv6 was standardized in 1995 as its successor to provide enhanced capabilities and address IPv4 technological limitations, most notable of which was the anticipated exhaustion of address space (Deering & Hinden, 1995). While the two protocols have some functional similarities, they are distinct and not backward compatible; IPv4-only devices cannot communicate directly with IPv6-only devices and vice-versa. Consequently, organizations wishing to take full advantage of the enhanced features of IPv6 must upgrade their entire network infrastructure and end devices to support IPv6, while at the same time maintaining IPv4 support for legacy systems that will not or cannot be upgraded. The costs and risks associated with upgrading an entire network to support a new protocol with no intrinsic return on investment has acted as a disincentive for IPv6 adoption. To be sure, the transition of the Internet to IPv6 has certainly taken a leisurely pace over the past twenty years. Given the slow pace of adoption, it is understandable that many doubted, and may still doubt that IPv6 will ever become the dominant Internet protocol and replace IPv4. However, in line with diffusion of innovations theory, it is the case with many innovations that potential adopters do not perceive any relative advantage, thus leading to a particularly slow adoption take-up rate. This is especially true with communications technologies that have high interdependence and require a critical mass of users before adoption becomes self-sustaining and rapidly accelerates (Rogers 2003). The goal of this paper is to provide empirical evidence showing that IPv6 adoption has reached critical mass and is now in a phase of accelerating adoption projected to continue. A methodology for monitoring the quality of IPv6 enablement and global IPv6 support is also provided so that the user experience over IPv6 can be assessed against the IPv4 baseline
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