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Computing infrastructure issues in distributed communications systems : a survey of operating system transport system architectures
The performance of distributed applications (such as file transfer, remote login, tele-conferencing, full-motion video, and scientific visualization) is influenced by several factors that interact in complex ways. In particular, application performance is significantly affected both by communication infrastructure factors and computing infrastructure factors. Several communication infrastructure factors include channel speed, bit-error rate, and congestion at intermediate switching nodes. Computing infrastructure factors include (among other things) both protocol processing activities (such as connection management, flow control, error detection, and retransmission) and general operating system factors (such as memory latency, CPU speed, interrupt and context switching overhead, process architecture, and message buffering). Due to a several orders of magnitude increase in network channel speed and an increase in application diversity, performance bottlenecks are shifting from the network factors to the transport system factors.This paper defines an abstraction called an "Operating System Transport System Architecture" (OSTSA) that is used to classify the major components and services in the computing infrastructure. End-to-end network protocols such as TCP, TP4, VMTP, XTP, and Delta-t typically run on general-purpose computers, where they utilize various operating system resources such as processors, virtual memory, and network controllers. The OSTSA provides services that integrate these resources to support distributed applications running on local and wide area networks.A taxonomy is presented to evaluate OSTSAs in terms of their support for protocol processing activities. We use this taxonomy to compare and contrast five general-purpose commercial and experimental operating systems including System V UNIX, BSD UNIX, the x-kernel, Choices, and Xinu
Deep Space Network information system architecture study
The purpose of this article is to describe an architecture for the Deep Space Network (DSN) information system in the years 2000-2010 and to provide guidelines for its evolution during the 1990s. The study scope is defined to be from the front-end areas at the antennas to the end users (spacecraft teams, principal investigators, archival storage systems, and non-NASA partners). The architectural vision provides guidance for major DSN implementation efforts during the next decade. A strong motivation for the study is an expected dramatic improvement in information-systems technologies, such as the following: computer processing, automation technology (including knowledge-based systems), networking and data transport, software and hardware engineering, and human-interface technology. The proposed Ground Information System has the following major features: unified architecture from the front-end area to the end user; open-systems standards to achieve interoperability; DSN production of level 0 data; delivery of level 0 data from the Deep Space Communications Complex, if desired; dedicated telemetry processors for each receiver; security against unauthorized access and errors; and highly automated monitor and control
Performance analysis of CCSDS path service
A communications service, called Path Service, is currently being developed by the Consultative Committee for Space Data Systems (CCSDS) to provide a mechanism for the efficient transmission of telemetry data from space to ground for complex space missions of the future. This is an important service, due to the large volumes of telemetry data that will be generated during these missions. A preliminary analysis of performance of Path Service is presented with respect to protocol-processing requirements and channel utilization
Device-Based Isolation for Securing Cryptographic Keys
In this work, we describe an eective device-based isolation
approach for achieving data security. Device-based isolation
leverages the proliferation of personal computing devices to
provide strong run-time guarantees for the condentiality of
secrets. To demonstrate our isolation approach, we show its
use in protecting the secrecy of highly sensitive data that
is crucial to security operations, such as cryptographic keys
used for decrypting ciphertext or signing digital signatures.
Private key is usually encrypted when not used, however,
when being used, the plaintext key is loaded into the memory
of the host for access. In our threat model, the host may
be compromised by attackers, and thus the condentiality of
the host memory cannot be preserved. We present a novel
and practical solution and its prototype called DataGuard to
protect the secrecy of the highly sensitive data through the
storage isolation and secure tunneling enabled by a mobile
handheld device. DataGuard can be deployed for the key
protection of individuals or organizations
An Outline of Security in Wireless Sensor Networks: Threats, Countermeasures and Implementations
With the expansion of wireless sensor networks (WSNs), the need for securing
the data flow through these networks is increasing. These sensor networks allow
for easy-to-apply and flexible installations which have enabled them to be used
for numerous applications. Due to these properties, they face distinct
information security threats. Security of the data flowing through across
networks provides the researchers with an interesting and intriguing potential
for research. Design of these networks to ensure the protection of data faces
the constraints of limited power and processing resources. We provide the
basics of wireless sensor network security to help the researchers and
engineers in better understanding of this applications field. In this chapter,
we will provide the basics of information security with special emphasis on
WSNs. The chapter will also give an overview of the information security
requirements in these networks. Threats to the security of data in WSNs and
some of their counter measures are also presented
The Design of a System Architecture for Mobile Multimedia Computers
This chapter discusses the system architecture of a portable computer, called Mobile Digital Companion, which provides support for handling multimedia applications energy efficiently. Because battery life is limited and battery weight is an important factor for the size and the weight of the Mobile Digital Companion, energy management plays a crucial role in the architecture. As the Companion must remain usable in a variety of environments, it has to be flexible and adaptable to various operating conditions. The Mobile Digital Companion has an unconventional architecture that saves energy by using system decomposition at different levels of the architecture and exploits locality of reference with dedicated, optimised modules. The approach is based on dedicated functionality and the extensive use of energy reduction techniques at all levels of system design. The system has an architecture with a general-purpose processor accompanied by a set of heterogeneous autonomous programmable modules, each providing an energy efficient implementation of dedicated tasks. A reconfigurable internal communication network switch exploits locality of reference and eliminates wasteful data copies
IPv6 Network Mobility
Network Authentication, Authorization, and Accounting has
been used since before the days of the Internet as we know it
today. Authentication asks the question, âWho or what are
you?â Authorization asks, âWhat are you allowed to do?â And fi nally,
accounting wants to know, âWhat did you do?â These fundamental
security building blocks are being used in expanded ways today. The
fi rst part of this two-part series focused on the overall concepts of
AAA, the elements involved in AAA communications, and highlevel
approaches to achieving specifi c AAA goals. It was published in
IPJ Volume 10, No. 1[0]. This second part of the series discusses the
protocols involved, specifi c applications of AAA, and considerations
for the future of AAA
Space Generic Open Avionics Architecture (SGOAA) reference model technical guide
This report presents a full description of the Space Generic Open Avionics Architecture (SGOAA). The SGOAA consists of a generic system architecture for the entities in spacecraft avionics, a generic processing architecture, and a six class model of interfaces in a hardware/software system. The purpose of the SGOAA is to provide an umbrella set of requirements for applying the generic architecture interface model to the design of specific avionics hardware/software systems. The SGOAA defines a generic set of system interface points to facilitate identification of critical interfaces and establishes the requirements for applying appropriate low level detailed implementation standards to those interface points. The generic core avionics system and processing architecture models provided herein are robustly tailorable to specific system applications and provide a platform upon which the interface model is to be applied
Active networks: an evolution of the internet
Active Networks can be seen as an evolution of the classical model of packet-switched networks. The traditional and âpassiveâ network model is based on a static definition of the network node behaviour. Active Networks propose an âactiveâ model where the intermediate nodes (switches and routers) can load and execute user code contained in the data units (packets). Active Networks are a programmable network model, where bandwidth and computation are both considered shared network resources. This approach opens up new interesting research fields. This paper gives a short introduction of Active
Networks, discusses the advantages they introduce and presents the research advances in this field
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