51,724 research outputs found
Managing community membership information in a small-world grid
As the Grid matures the problem of resource discovery across communities,
where resources now include computational services, is becoming more
critical. The number of resources available on a world-wide grid is set to grow
exponentially in much the same way as the number of static web pages on
the WWW. We observe that the world-wide resource discovery problem can
be modelled as a slowly evolving very-large sparse-matrix where individual
matrix elements represent nodes’ knowledge of one another. Blocks in the
matrix arise where nodes offer more than one service. Blocking effects also
arise in the identification of sub-communities in the Grid. The linear algebra
community has long been aware of suitable representations of large, sparse
matrices. However, matrices the size of the world-wide grid potentially number
in the billions, making dense solutions completely intractable. Distributed
nodes will not necessarily have the storage capacity to store the addresses of
any significant percentage of the available resources. We discuss ways of modelling
this problem in the regime of a slowly changing service base including
phenomena such as percolating networks and small-world network effects
Location Independent Names for Nomadic Computers
Recent advances in the Domain Name System (DNS) and the Dynamic Host Configuration Protocol (DHCP) have enabled a new approach to supporting mobile users: location independent naming. In this approach, machines use the same hostname from any internet location, but use an IP address that corresponds to their current location. We describe a protocol that implements location independent naming for nomadic computers, i.e., machines that do not need transparent mobility. Our protocol allows hosts to move across security domains, uses existing protocols, and preserves existing trust relationships. Therefore, it preserves the performance and security of normal IP for nomadic computers at the expense of not providing the transparent mobility of Mobile IP. We contend that this is a reasonable trade-off for nomadic computing
Efficient Batch Update of Unique Identifiers in a Distributed Hash Table for Resources in a Mobile Host
Resources in a distributed system can be identified using identifiers based
on random numbers. When using a distributed hash table to resolve such
identifiers to network locations, the straightforward approach is to store the
network location directly in the hash table entry associated with an
identifier. When a mobile host contains a large number of resources, this
requires that all of the associated hash table entries must be updated when its
network address changes.
We propose an alternative approach where we store a host identifier in the
entry associated with a resource identifier and the actual network address of
the host in a separate host entry. This can drastically reduce the time
required for updating the distributed hash table when a mobile host changes its
network address. We also investigate under which circumstances our approach
should or should not be used. We evaluate and confirm the usefulness of our
approach with experiments run on top of OpenDHT.Comment: To be presented at the 2010 International Workshop on Cloud
Computing, Applications and Technologie
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
Mobility Study for Named Data Networking in Wireless Access Networks
Information centric networking (ICN) proposes to redesign the Internet by
replacing its host-centric design with information-centric design.
Communication among entities is established at the naming level, with the
receiver side (referred to as the Consumer) acting as the driving force behind
content delivery, by interacting with the network through Interest message
transmissions. One of the proposed advantages for ICN is its support for
mobility, by de-coupling applications from transport semantics. However, so
far, little research has been conducted to understand the interaction between
ICN and mobility of consuming and producing applications, in protocols purely
based on information-centric principles, particularly in the case of NDN. In
this paper, we present our findings on the mobility-based performance of Named
Data Networking (NDN) in wireless access networks. Through simulations, we show
that the current NDN architecture is not efficient in handling mobility and
architectural enhancements needs to be done to fully support mobility of
Consumers and Producers.Comment: to appear in IEEE ICC 201
Simulating Wde-area Replication
We describe our experiences with simulating replication algorithms for use in far flung distributed systems. The algorithms under scrutiny mimic epidemics. Epidemic algorithms seem to scale and adapt to change (such as varying replica sets) well. The loose consistency guarantees they make seem more useful in applications where availability strongly outweighs correctness; e.g., distributed name service
A Flexible and Secure Deployment Framework for Distributed Applications
This paper describes an implemented system which is designed to support the
deployment of applications offering distributed services, comprising a number
of distributed components. This is achieved by creating high level placement
and topology descriptions which drive tools that deploy applications consisting
of components running on multiple hosts. The system addresses issues of
heterogeneity by providing abstractions over host-specific attributes yielding
a homogeneous run-time environment into which components may be deployed. The
run-time environments provide secure binding mechanisms that permit deployed
components to bind to stored data and services on the hosts on which they are
running.Comment: 2nd International Working Conference on Component Deployment (CD
2004), Edinburgh, Scotlan
Internet diffusion vs. the crisis of the new economy
The diffusion of Internet in the world, both in terms of 'users' and 'information suppliers' is continuously and constantly increasing. This market growth is based on a development that follows the usual behavior of technological innovation diffusion (S-shaped logistic curve), so it is allowed to obtain reliable forecasts about the future market trend. Nevertheless, despite the continuous growth of the 'target', the E-business seems to be in a crucial situation absolutely unpredictable since few moths ago, when viceversa looked as the main driving force of the 'new economy' attacking the boundaries of the 'global market'. The objective of this paper is to analyze the potentialities of the growing market, through the actual and forecasted number of users, and the condition of the general offer, in terms of typology and quality of the services supplied, trying to identify a reason for this crisis. Keywords: Internet, E-business, Global Market, New economy
- …