95 research outputs found
Towards a GNU/Linux IEEE 802.21 Implementation
Abstract-Multiaccess mobile devices and overlapping wireless network deployments have emerged as a next generation network fixture. To make the most of all available networks, mobile devices should be capable of handing over between heterogeneous networks seamlessly and automatically. At the same time, operators should be able to steer network attachment based on their criteria. Although several cross layer mechanisms have been proposed in recent years, only the Media Independent Handover (MIH) Services framework has advanced in any of the established standardization bodies. This paper presents a blueprint for a GNU/Linux implementation of IEEE 802.21. We review the salient points of the standard, introduce our software implementation architecture, detail information gathering in GNU/Linux, and show how our prototype implementation can be used in practice. In contrast with prior published work, this paper presents a real IEEE 802.21 implementation, not an abstracted or reduced MIH-like framework, tested and empirically evaluated over real heterogeneous networks
Distributed Information Object Resolution
The established host-centric networking paradigm is chal-lenged due to handicaps related with disconnected opera-tion, mobility, and broken locator/identifier semantics. This paper soberly examines another topic of great interest: distributed information object resolution. After recapping the notion of an information object, we review object resolution in today’s Internet which is based on Uniform Resource Identifiers (URIs). We revisit the implications of DNS involvement in URI resolution and discuss how two different types of content distribution networks work with respect to name resolution. Then we evaluate proposals championing the replacement of DNS with alternatives based on distributed hash tables. We present the pros and cons and highlight the importance of latency in resolution. The paper positions these issues in the context of a Network of Information (NetInf) and concludes with open research topics in the area. 1
A comparative study of aggregate TCP retransmission rates
Segment retransmissions are an essential tool in assuring reliable end-to-end
communication in the Internet. Their crucial role in TCP design and operation
has been studied extensively, in particular with respect to identifying
non-conformant, buggy, or underperforming behaviour. However, TCP segment
retransmissions are often overlooked when examining and analyzing large traffic
traces. In fact, some have come to believe that retransmissions are a rare
oddity, characteristically associated with faulty network paths, which,
typically, tend to disappear as networking technology advances and link
capacities grow. We find that this may be far from the reality experienced by
TCP flows. We quantify aggregate TCP segment retransmission rates using
publicly available network traces from six passive monitoring points attached
to the egress gateways at large sites. In virtually half of the traces examined
we observed aggregate TCP retransmission rates exceeding 1%, and of these,
about half again had retransmission rates exceeding 2%. Even for sites with low
utilization and high capacity gateway links, retransmission rates of 1%, and
sometimes higher, were not uncommon. Our results complement, extend and bring
up to date partial and incomplete results in previous work, and show that TCP
retransmissions continue to constitute a non-negligible percentage of the
overall traffic, despite significant advances across the board in
telecommunications technologies and network protocols. The results presented
are pertinent to end-to-end protocol designers and evaluators as they provide a
range of "realistic" scenarios under which, and a "marker" against which,
simulation studies can be configured and calibrated, and future protocols
evaluated
Towards a GNU/Linux IEEE 802.21 Implementation
Abstract-Multiaccess mobile devices and overlapping wireless network deployments have emerged as a next generation network fixture. To make the most of all available networks, mobile devices should be capable of handing over between heterogeneous networks seamlessly and automatically. At the same time, operators should be able to steer network attachment based on their criteria. Although several cross layer mechanisms have been proposed in recent years, only the Media Independent Handover (MIH) Services framework has advanced in any of the established standardization bodies. This paper presents a blueprint for a GNU/Linux implementation of IEEE 802.21. We review the salient points of the standard, introduce our software implementation architecture, detail information gathering in GNU/Linux, and show how our prototype implementation can be used in practice. In contrast with prior published work, this paper presents a real IEEE 802.21 implementation, not an abstracted or reduced MIH-like framework, tested and empirically evaluated over real heterogeneous networks
Scenarios and research issues for a network of information
This paper describes ideas and items of work within the
framework of the EU-funded 4WARD project. We present
scenarios where the current host-centric approach to infor-
mation storage and retrieval is ill-suited for and explain
how a new networking paradigm emerges, by adopting the
information-centric network architecture approach, which
we call Network of Information (NetInf). NetInf capital-
izes on a proposed identifier/locator split and allows users
to create, distribute, and retrieve information using a com-
mon infrastructure without tying data to particular hosts.
NetInf introduces the concepts of information and data ob-
jects. Data objects correspond to the particular bits and
bytes of a digital object, such as text file, a specific encod-
ing of a song or a video. Information objects can be used
to identify other objects irrespective of their particular dig-
ital representation. After discussing the benefits of such an
indirection, we consider the impact of NetInf with respect
to naming and governance in the Future Internet. Finally,
we provide an outlook on the research scope of NetInf along
with items for future work
Using Media to Teach Different Learning Style in X and XII grade of Vocational School of Medical Nusantara Pamekasan
The purpose of this article is knowing the use of media to teach different learning style of student in Vocational School of Medical Nusantara Pamekasan. In this article, the researcher got the data by doing direct interview with one of the English teacher in that school. Based on the data, this article explain about the use of media to teach students with differet learning style
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