3,554 research outputs found
Blocking Java Applets at the Firewall
This paper explores the problem of protecting a site on the Internet against hostile external Java applets while allowing trusted internal applets to run. With careful implementation, a site can be made resistant to current Java security weaknesses as well as those yet to be discovered. In addition, we describe a new attack on certain sophisticated firewalls that is most effectively realized as a Java applet
Performance evaluation of an open distributed platform for realistic traffic generation
Network researchers have dedicated a notable part of their efforts
to the area of modeling traffic and to the implementation of efficient traffic
generators. We feel that there is a strong demand for traffic generators
capable to reproduce realistic traffic patterns according to theoretical
models and at the same time with high performance. This work presents an open
distributed platform for traffic generation that we called distributed
internet traffic generator (D-ITG), capable of producing traffic (network,
transport and application layer) at packet level and of accurately replicating
appropriate stochastic processes for both inter departure time (IDT) and
packet size (PS) random variables. We implemented two different versions of
our distributed generator. In the first one, a log server is in charge of
recording the information transmitted by senders and receivers and these
communications are based either on TCP or UDP. In the other one, senders and
receivers make use of the MPI library. In this work a complete performance
comparison among the centralized version and the two distributed versions of
D-ITG is presented
A Generic Deployment Framework for Grid Computing and Distributed Applications
Deployment of distributed applications on large systems, and especially on
grid infrastructures, becomes a more and more complex task. Grid users spend a
lot of time to prepare, install and configure middleware and application
binaries on nodes, and eventually start their applications. The problem is that
the deployment process is composed of many heterogeneous tasks that have to be
orchestrated in a specific correct order. As a consequence, the automatization
of the deployment process is currently very difficult to reach. To address this
problem, we propose in this paper a generic deployment framework allowing to
automatize the execution of heterogeneous tasks composing the whole deployment
process. Our approach is based on a reification as software components of all
required deployment mechanisms or existing tools. Grid users only have to
describe the configuration to deploy in a simple natural language instead of
programming or scripting how the deployment process is executed. As a toy
example, this framework is used to deploy CORBA component-based applications
and OpenCCM middleware on one thousand nodes of the French Grid5000
infrastructure.Comment: The original publication is available at http://www.springerlink.co
Traffic measurement and analysis
Measurement and analysis of real traffic is important to gain knowledge
about the characteristics of the traffic. Without measurement, it is
impossible to build realistic traffic models. It is recent that data
traffic was found to have self-similar properties. In this thesis work
traffic captured on the network at SICS and on the Supernet, is shown to
have this fractal-like behaviour. The traffic is also examined with
respect to which protocols and packet sizes are present and in what
proportions. In the SICS trace most packets are small, TCP is shown to be
the predominant transport protocol and NNTP the most common application.
In contrast to this, large UDP packets sent between not well-known ports
dominates the Supernet traffic. Finally, characteristics of the client
side of the WWW traffic are examined more closely. In order to extract
useful information from the packet trace, web browsers use of TCP and HTTP
is investigated including new features in HTTP/1.1 such as persistent
connections and pipelining. Empirical probability distributions are
derived describing session lengths, time between user clicks and the
amount of data transferred due to a single user click. These probability
distributions make up a simple model of WWW-sessions
Software product description
An overview of the MultiNet system is presented. Services, supported configurations, remote printer services, netstat, netcontrol, DECnet interoperability services, and programming libraries are briefly described
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