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Full-Text Articles in Computer Engineering
Design Tradeoffs For Embedded Network Processors, Tilman Wolf, Mark Franklin, Edward W. Spitznagel
Design Tradeoffs For Embedded Network Processors, Tilman Wolf, Mark Franklin, Edward W. Spitznagel
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Demands for flexible processing has moved general-purpose processing into the data path of networks. With the development of System-On-a-Chip technology, it is possible to put several processors with memory and I/O components on a single ASIC. We present a model of such a system with a simple performance metric and show how the number of processors and cache sizes can be optimized for a given workload. Based on a telecommunications benchmark we show the results of such an optimization and discuss how specialied hardware and appropriate scheduling can further improve system performance.
Synthesizer, A Pattern Language For Designing Digital Modular Synthesis Software, Thomas V. Judkins, Christopher D. Gill
Synthesizer, A Pattern Language For Designing Digital Modular Synthesis Software, Thomas V. Judkins, Christopher D. Gill
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Synthesizer is a pattern language for designing digital synthesizers using modular synthesis in software to generate sound. Software developed according to this pattern language emulates the abilities of an analog synthesizer. Modular synthesis is one of the oldest sound synthesis techniques. It was used in the earliest analog synthesizers, like the Moog [1] and ARP [2]. These machines introduced the oscillator-filter-amplifier paradigm, where sound generated by an oscillator is passed through a series of filters and amplifers before being sent to a speaker. These first machines had physical modules through which electrical signals were passed. These modules can be emulated …
Data Archiving With The Srb*, Jinghua Zhou
Data Archiving With The Srb*, Jinghua Zhou
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We use the SRB (Storage Request Broker) middleware to design and implement a storage archival system which will be used to archive Neuroscience data. As part of the design process, we developed and used an experimenter's workbench to measure SRB performance. These experiments improved our understanding of both the functionality and the performance of the SRB. This technical report describes the scripts in the experimenter's workbench, the archiving scripts, and performance measurements.
Coordination And Mobility, Gruia-Catalin Roman, Amy L. Murphy, Gian Pietro Picco
Coordination And Mobility, Gruia-Catalin Roman, Amy L. Murphy, Gian Pietro Picco
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Mobility entails the study of systems in which components change location, in a voluntary or involuntary manner, and move across a space that may be defined to be either logical or physical. Coordination is concerned with what happens when two or more components come in contact with each other. In this paper we put forth a working definition of coordinatoin, we construct argumetns that demonstrate that coordination is central to understanding mobility, we explore the intellectual richness of the notion of coordination, and we consider the practical implications of coordination-centered system design strategies. We develop these ideas in two steps. …
A Rate-Based End-To-End Multicast Congestion Control Protocol, Sherlia Shi, Marcel Waldvogel
A Rate-Based End-To-End Multicast Congestion Control Protocol, Sherlia Shi, Marcel Waldvogel
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Current reliable multicast protocols do not have scalable congestion control mechanisms and this deficiency leads to concerns that multicast deployment may endanger stability of the network. In this paper, we present a sender-based approach for multicast congestion control targeted towards reliable bulk data transfer. We assume that there are a few bottleneck links in a large scale multicast group at any time period and these bottlenecks persist long enough to be identified and adapted to. Our work focus on dynamically identifying the worst congested path in the multicast tree and obtaining TCP-friendly throughput on this selected path. We device novel …
Profile-Based Routing: A New Framework For Mpls Traffic Engineering, Subhash Suri, Marcel Waldvogel, Priyank Ramesh Warkhede
Profile-Based Routing: A New Framework For Mpls Traffic Engineering, Subhash Suri, Marcel Waldvogel, Priyank Ramesh Warkhede
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We present a new algorithm and framework for dynamic routing of bandwidth guaranteed flows. The problem is motivated by the need to dynamically set up bandwidth guaranteed paths in carrier and ISP networks. Traditional routing algorithms such as minimum hop routing or widest path routing do not take advantage of any knowledge about the traffic distribution or ingress-egress pairs, and therefore can often lead to severe network underutilization. Our work is inspired by the recently proposed "minimum interference routing" algorithm (MIRA) of Kodialam and Lakshman, but it improves on their approach in several ways. Our main idea is to use …
On Maintaining Group Membership Data In Ad Hoc Networks, Gruia-Catalin Roman, Qingfeng Huang, Ali Hazemi
On Maintaining Group Membership Data In Ad Hoc Networks, Gruia-Catalin Roman, Qingfeng Huang, Ali Hazemi
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The design of ad hoc mobile applications often requires the availability of a consistent view of the application state among the participating hosts. Essential to constructing a consistent view is the ability to know what hosts are within proximity of each other, i.e., form a group in support of the particular application. In this paper we propose an algorithm that allows hosts within communication range to maintain a consistent view of the group membership despite movement and frequent disconnections. The novel features of this algorithm are its reliance on location information and a conservative notion of logical connectivity that creates …
Programming Active Networks Using Active Pipes, Ralph Keller, Jeyashankher Ramamirtham, Tilman Wolf, Bernhard Plattner
Programming Active Networks Using Active Pipes, Ralph Keller, Jeyashankher Ramamirtham, Tilman Wolf, Bernhard Plattner
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Active networks allow customized processing of data traffic within the network which can be used by applications to improve the quality of their sessions. To simplify development of active applications in a heterogeneous environment, we propose active network pipes as a programming abstraction to specify transmission and processing requirements. We describe a routing algorithm that maps application session requirements onto network resources and determines an optimal route through the network transiting all required processing sites. Additionally, we propose a network software architecture to implement the functionality required to support active pipes.
Codeweave: Exploring Fine-Grained Mobility Of Code, Cecilia Mascolo, Gian Pietro Picco, Gruia-Catalin Roman
Codeweave: Exploring Fine-Grained Mobility Of Code, Cecilia Mascolo, Gian Pietro Picco, Gruia-Catalin Roman
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This paper explores the range of constructs and issues facing the designer of mobile code systems which allow for the unit of mobility to be finer-grained than that of execution. Mobile UNITY, a notation and proof logic for mobile computing, provides for this research a clean abstract setting, i.e., unconstrained by compilation and performance considerations traditionally associated with programming language design. Within the context of Mobile UNITY, we take the extreme view that every line of code and every variable declaration is potentially mobile, i.e., it may be duplicated and/or moved from one program contxt to another on the same …
Configuring Sessions In Programmable Networks, Sumi Choi, Jonathan Turner, Tilman Wolf
Configuring Sessions In Programmable Networks, Sumi Choi, Jonathan Turner, Tilman Wolf
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The provision of advanced computational services within networks is rapidly becoming both feasible and economical. We present a general approach to the problem of configuring application sessions that require intermediate processing by showing how the session configuration problem can be transformed to a conventional shortest path problem. We show, through a series of examples, that the method can be applied to a wide variety of different situations.
Recognition And Verification Of Design Patterns, Michael P. Plezbert, Ron K. Cytron
Recognition And Verification Of Design Patterns, Michael P. Plezbert, Ron K. Cytron
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In this paper we consider the automatic discovery of design (programming) patterns. While patterns have surfaced as an effective mechanism for authoring and understanding compelx software, popular languages lack facilities for direct specification of patterns or verification of pattern usage in program specifications. Static analysis for patterns is provably undecidable; we focus on discovery and verification of patterns by analyzing dynamic sequences of method calls on object. We show a proof-of-concept of our approach by presenting the results of analyzing a Java program for Iterator patterns.
Almi: An Application Level Multicast Infrastructure, Dimitrios Pendarakis, Sherlia Shi, Dinesh Verma, Marcel Waldvogel
Almi: An Application Level Multicast Infrastructure, Dimitrios Pendarakis, Sherlia Shi, Dinesh Verma, Marcel Waldvogel
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The IP multicast model allows scalable and efficient multi-party communication, particularly for groups of large size. However, deployment of IP multicast requires substantial infrastructure modifications and is hampered by a host of unresolved open problems such as reliability, flow and congestion control, security and access control. Motivated by these problems, we have designed and implemented ALMI, an application level group communication middleware, which does not rely on network infrastructure support and thus, allows accelerated deployment and simplified configuration at the cost of a relatively small increase in traffic load. ALMI is tailored toward support of multicast groups of relatively small …
Parallel Fpga Programming Over Backplane Chassis, John Lockwood, Tom Mclaughlin, Tom Chaney, Yuhua Chen, Fred Rosenberger, Alex Chandra, Jon Turner
Parallel Fpga Programming Over Backplane Chassis, John Lockwood, Tom Mclaughlin, Tom Chaney, Yuhua Chen, Fred Rosenberger, Alex Chandra, Jon Turner
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For systems with a large number of FPGAs, where a design is instantiated across multiple FPGAs in a chassis, an efficient mechanism of programming the FPGA devices is needed. The mechanism described herein allows multiple FPGAs to be programmed across a backplane. Only a single configuration PROM is required to store the configuration for the multiple instances of the design. When the system boots, all FPGAs are programmed in parallel. This design is applicable to any system which contains a multiple board system which has instances of identical FPGA implementations distributed across the boards. Signal integrity of signals is considered.
Hello, World: A Simple Application For The Field Programmable Port Extender (Fpx), John Lockwood, David Lim
Hello, World: A Simple Application For The Field Programmable Port Extender (Fpx), John Lockwood, David Lim
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The FPX provides simple and fast mechanisms to process cells or packets. By performing all computations in FPGA hardware, cells and packets can be processing at the full line speed of the card [currently 2.4 Gbits/sec]. A sample application, called 'Hello World' has been developed that illustrates how easily an application can be implemented on the FPX. This application uses the FPGA hardware to search for a string on a particular flow and selectively replace contents of the payload. The resulting circuit operates at 119 MHz on a Xilinx XCV 1000E-FG680-7, and occupies less than 1% of the available gates …
Plugin Management For Active Network, Sumi Y. Choi
Plugin Management For Active Network, Sumi Y. Choi
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The purpose of this document is to present the overview of tte plugin management architecture and the description of the software developed for the scalable, high performance active network node project in Washington University, St. Louis. The plugin management is a user space daemon program that runs at the code(plugin) server and at the active network component of a router or a switch port processor. The running programs cooperate to load plugins from the code server to the active network component. This software is intended to be used among multiple platforms.
Lime: A Middleware For Physical And Logical Mobility, Gian Pietro Picco, Amy L. Murphy, Gruia-Catalin Roman
Lime: A Middleware For Physical And Logical Mobility, Gian Pietro Picco, Amy L. Murphy, Gruia-Catalin Roman
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LIME is a middleware supporting the development of applications that exhibit physical mobility of hosts, logical mobility of agents, or both. LIME adopts a coordination perspective inspired by work on the Linda model. The context for computation, represented in Linda by a globally accessible, persistent tuple space, is represented in LIME by transient sharing of the tuple spaces carried by each individual mobile unit. Linda tuple spaces are also extended with a notion of location and with the ability to react to a given state. The hypothesis underlying our work is that the resulting model provides a minimalist set of …
The Design And Performance Of Meta-Programming Mechanisms For Object Request Broker Middleware, Nanbor Wang, Kirthika Parameswaran, Douglass Schmidt
The Design And Performance Of Meta-Programming Mechanisms For Object Request Broker Middleware, Nanbor Wang, Kirthika Parameswaran, Douglass Schmidt
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Distributed object computing (DOC) middleware shields developers from many tedious and error-prone aspects of programming distribued applications. Without proper support from the middleware, however, it can be hard to evolve distributed applications after they are deployed. Therefore, DOC middleware should support meta-programming mechanisms, such as smart proxies and interceptors, that improve the adaptability of distributed applications by allowing their behavior to be modified without drastically changing existing software. This paper presents three contributions to the study of metaprogramming mechanisms for DOC middleware. First, it illustrates, compares, and contrasts several meta-programming mechanisms from an application developer's perspective. Second, it outlines the …