Architectures for the Future Networks and the Next Generation Internet: A Survey

Networking research funding agencies in the USA, Europe, Japan, and other countries are encouraging research on revolutionary networking architectures that may or may not be bound by the restrictions of the current TCP/IP based Internet. We present a comprehensive survey of such research projects and activities. The topics covered include various testbeds for experimentations for new architectures, new security mechanisms, content delivery mechanisms, management and control frameworks, service architectures, and routing mechanisms. Delay/Disruption tolerant networks, which allow communications even when complete end-to-end path is not available, are also discussed

A Logically Centralized Approach for Control and Management of Large Computer Networks

Management of large enterprise and Internet Service Provider networks is a complex, error-prone, and costly challenge. It is widely accepted that the key contributors to this complexity are the bundling of control and data forwarding in traditional routers and the use of fully distributed protocols for network control. To address these limitations, the networking research community has been pursuing the vision of simplifying the functional role of a router to its primary task of packet forwarding. This enables centralizing network control at a decision plane where network-wide state can be maintained, and network control can be centrally and consistently enforced. However, scalability and fault-tolerance concerns with physical centralization motivate the need for a more flexible and customizable approach. This dissertation is an attempt at bridging the gap between the extremes of distribution and centralization of network control. We present a logically centralized approach for the design of network decision plane that can be realized by using a set of physically distributed controllers in a network. This approach is aimed at giving network designers the ability to customize the level of control and management centralization according to the scalability, fault-tolerance, and responsiveness requirements of their networks. Our thesis is that logical centralization provides a robust, reliable, and efficient paradigm for management of large networks and we present several contributions to prove this thesis. For network planning, we describe techniques for optimizing the placement of network controllers and provide guidance on the physical design of logically centralized networks. For network operation, algorithms for maintaining dynamic associations between the decision plane and network devices are presented, along with a protocol that allows a set of network controllers to coordinate their decisions, and present a unified interface to the managed network devices. Furthermore, we study the trade-offs in decision plane application design and provide guidance on application state and logic distribution. Finally, we present results of extensive numerical and simulative analysis of the feasibility and performance of our approach. The results show that logical centralization can provide better scalability and fault-tolerance while maintaining performance similarity with traditional distributed approach

Automating Performance Diagnosis in Networked Systems

Diagnosing performance degradation in distributed systems is a complex and difficult task. Software that performs well in one environment may be unusably slow in another, and determining the root cause is time-consuming and error-prone, even in environments in which all the data may be available. End users have an even more difficult time trying to diagnose system performance, since both software and network problems have the same symptom: a stalled application. The central thesis of this dissertation is that the source of performance stalls in a distributed system can be automatically detected and diagnosed with very limited information: the dependency graph of data flows through the system, and a few counters common to almost all data processing systems. This dissertation presents FlowDiagnoser, an automated approach for diagnosing performance stalls in networked systems. FlowDiagnoser requires as little as two bits of information per module to make a diagnosis: one to indicate whether the module is actively processing data, and one to indicate whether the module is waiting on its dependents. To support this thesis, FlowDiagnoser is implemented in two distinct environments: an individual host's networking stack, and a distributed streams processing system. In controlled experiments using real applications, FlowDiagnoser correctly diagnoses 99% of networking-related stalls due to application, connection-specific, or network-wide performance problems, with a false positive rate under 3%. The prototype system for diagnosing messaging stalls in a commercial streams processing system correctly finds 93% of message-processing stalls, with a false positive rate of 2%

Study of the Applicability of Model-Driven Metodologies for the Design of Autonomic Behaviours

Verkonhallinta on tällä hetkellä monimutkaista ja vaatii korkeat kustannukset. Näin ollen verkkoteollisuus tarvitsee verkonhallinnan alueelle muutoksen, joka vähentää näitä kahta aspektia. Ratkaisu perustuu siihen, että osa hallintatoiminnoista, jotka tarvitsevat ihmisen puuttumista, siirretään itse verkkoon, luoden autonomisia verkkoja. EFIPSANS on projekti, joka tähtää IPv6:n ja siihen liittyvien protokollien ominaisuuksien hyödyntämiseen ja laajentamiseen, jotta IPv6-pohjaisten autonomisten ja itseohjautuvien verkkojen ja palvelujen realisointi olisi mahdollista. EFIPSANS:n kehittämät itseohjautuvuuden ominaisuudet tunnetaan Autonomisina Käyttäytymisinä, jotka toteutetaan järjestelmässä, kuten reitittimessä, tai kokonaisen verkon muodostamassa järjestelmässä, kontrollointisilmukoiden avulla. Projektissa suunniteltu arkkitehtuuri Autonomisten Käyttäytymisten suunnitteluun ja toteuttamiseen kutsutaan Yleiseksi Autonomiseksi Verkkoarkkitehtuuriksi (GANA). Diplomityön tavoitteena on edistää Malliperusteisen Metodologian ja siihen liittyvän Työkaluketjun kehittämistä, jota voidaan soveltaa Autonomisten Käyttäytymisten suunnitteluun, simulointiin, todentamiseen ja hyväksymiseen. Tämä diplomityö alkaa johdannolla EFIPSANS projektiin, pääpainonaan eri autonomiset käyttäytymiset, kuin myös GANA referenssimalli. Sen jälkeen käsittelemme Malliperusteista Metodologiaa sekä useista erityyppisistä työkaluista koostuvan Työkaluketjun toteutuksen yksityiskohtia. Lopulta käsittelemme toteutetun Työkaluketjun etuja ja rajoituksia.The complexity and costs needed for network management are currently very high, thus the networking industry is calling for a change in the network management area that would reduce these two aspects. The solution is based on moving some of the management tasks that involve human intervention into the network itself, creating autonomic networks. EFIPSANS is a project that aims at exploiting and extending the features of IPv6 and related protocols to enable the realization of IPv6-based autonomic and self-managing networks and services. The self-management features that EFIPSANS has developed are known as Autonomic Behaviours, which are realized by control-loops within a system e.g. a router or within the overall network as a system. The architecture developed within the project for designing and engineering Autonomic Behaviours is Generic Autonomic Network Architecture (GANA). The goal of this Master's Thesis is to contribute to the development of a Model-Driven Methodology and an associated Tool-Chain that can be applied for the design, simulation, verification and validation of Autonomic Behaviours. In this thesis, first, we give an overview on the EFIPSANS project, focusing on the different Autonomic Behaviours, as well as on the GANA reference model. Then, we discuss the identified Model-Driven Methodology and the implementation details of the Tool-Chain, which is orchestrated by several tools of different natures. Then, we show a step-by-step case study using the developed Tool-Chain. Finally, we discuss the benefits and the limitations of the implemented Tool-Chain

Efficient Groundness Analysis in Prolog

Boolean functions can be used to express the groundness of, and trace grounding dependencies between, program variables in (constraint) logic programs. In this paper, a variety of issues pertaining to the efficient Prolog implementation of groundness analysis are investigated, focusing on the domain of definite Boolean functions, Def. The systematic design of the representation of an abstract domain is discussed in relation to its impact on the algorithmic complexity of the domain operations; the most frequently called operations should be the most lightweight. This methodology is applied to Def, resulting in a new representation, together with new algorithms for its domain operations utilising previously unexploited properties of Def -- for instance, quadratic-time entailment checking. The iteration strategy driving the analysis is also discussed and a simple, but very effective, optimisation of induced magic is described. The analysis can be implemented straightforwardly in Prolog and the use of a non-ground representation results in an efficient, scalable tool which does not require widening to be invoked, even on the largest benchmarks. An extensive experimental evaluation is givenComment: 31 pages To appear in Theory and Practice of Logic Programmin

Towards Automated Network Configuration Management

Modern networks are designed to satisfy a wide variety of competing goals related to network operation requirements such as reachability, security, performance, reliability and availability. These high level goals are realized through a complex chain of low level configuration commands performed on network devices. As networks become larger, more complex and more heterogeneous, human errors become the most significant threat to network operation and the main cause of network outage. In addition, the gap between high-level requirements and low-level configuration data is continuously increasing and difficult to close. Although many solutions have been introduced to reduce the complexity of configuration management, network changes, in most cases, are still manually performed via low--level command line interfaces (CLIs). The Internet Engineering Task Force (IETF) has introduced NETwork CONFiguration (NETCONF) protocol along with its associated data--modeling language, YANG, that significantly reduce network configuration complexity. However, NETCONF is limited to the interaction between managers and agents, and it has weak support for compliance to high-level management functionalities. We design and develop a network configuration management system called AutoConf that addresses the aforementioned problems. AutoConf is a distributed system that manages, validates, and automates the configuration of IP networks. We propose a new framework to augment NETCONF/YANG framework. This framework includes a Configuration Semantic Model (CSM), which provides a formal representation of domain knowledge needed to deploy a successful management system. Along with CSM, we develop a domain--specific language called Structured Configuration language to specify configuration tasks as well as high--level requirements. CSM/SCL together with NETCONF/YANG makes a powerful management system that supports network--wide configuration. AutoConf supports two levels of verifications: consistency verification and behavioral verification. We apply a set of logical formalizations to verifying the consistency and dependency of configuration parameters. In behavioral verification, we present a set of formal models and algorithms based on Binary Decision Diagram (BDD) to capture the behaviors of forwarding control lists that are deployed in firewalls, routers, and NAT devices. We also adopt an enhanced version of Dyna-Q algorithm to support dynamic adaptation of network configuration in response to changes occurred during network operation. This adaptation approach maintains a coherent relationship between high level requirements and low level device configuration. We evaluate AutoConf by running several configuration scenarios such as interface configuration, RIP configuration, OSPF configuration and MPLS configuration. We also evaluate AutoConf by running several simulation models to demonstrate the effectiveness and the scalability of handling large-scale networks

Toward Automated Network Management and Operations.

Network management plays a fundamental role in the operation and well-being of today's networks. Despite the best effort of existing support systems and tools, management operations in large service provider and enterprise networks remain mostly manual. Due to the larger scale of modern networks, more complex network functionalities, and higher network dynamics, human operators are increasingly short-handed. As a result, network misconfigurations are frequent, and can result in violated service-level agreements and degraded user experience. In this dissertation, we develop various tools and systems to understand, automate, augment, and evaluate network management operations. Our thesis is that by introducing formal abstractions, like deterministic finite automata, Petri-Nets and databases, we can build new support systems that systematically capture domain knowledge, automate network management operations, enforce network-wide properties to prevent misconfigurations, and simultaneously reduce manual effort. The theme for our systems is to build a knowledge plane based on the proposed abstractions, allowing network-wide reasoning and guidance for network operations. More importantly, the proposed systems require no modification to the existing Internet infrastructure and network devices, simplifying adoption. We show that our systems improve both timeliness and correctness in performing realistic and large-scale network operations. Finally, to address the current limitations and difficulty of evaluating novel network management systems, we have designed a distributed network testing platform that relies on network and device virtualization to provide realistic environments and isolation to production networks.Ph.D.Computer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/78837/1/chenxu_1.pd

Requirements for a software maintenance support environment

This thesis surveys the field of software maintenance, and addresses the maintenance requirements of the Aerospace Industry, which is developing inige projects, running over many years, and sometimes safety critical in nature (e.g. ARIANE 5, HERMES, COLUMBUS). Some projects are collaborative between distributed European partners. The industry will have to cope in the near and far future with the maintenance of these products and it will be essential to improve the software maintenance process and the environments for maintenance. Cost effective software maintenance needs an efficient, high quality and homogeneous environment or Integrated Project Support Environment (IPSE). Most IPSE work has addressed software development, and lias not fully considered the requirements of software maintenance. The aim of this project is to draw up a set of priorities and requirements for a Maintenance IPSE. An IPSE, however can only support a software maintenance method. The first stage of this project is to deline 'software maintenance best practice' addressing the organisational, managerial and technical aspects, along with an evaluation of software maintenance tools for Aerospace systems. From this and an evaluation of current IPSEs, the requirements for a Software Maintenance Support Environment are presented for maintenance of Aerospace software

Difficult Work: The Politics Of Counter-Professionalism In Post-1945 Transnational American Fiction

This dissertation reads American and Asian American fictions that instigate feelings of discontent about American work. While literary scholars of white-collar work have examined anti-work sentiment as an unquestionably American phenomenon, they have yet to acknowledge the continuing global repercussions of the postwar American economy. I read transnational figures of work that query the ideology of American professionalism by mixing anti-work and anti-imperial feeling into the performance of white-collar work. Drawing from four forms of the novel that address a crisis of American domesticity—the postwar crime novel, the middlebrow travel novel, the multi-ethnic bildungsroman, and the post-9/11 finance novel—the dissertation reads low-grade, ambient affects, like anxiety or hesitation, to find a sideways reappraisal of a national work ethic. Minor feeling opens a new tendency in transnational American writing that I theorize as “counter-professionalism,” where the prefix “counter” produces multiple forms of resistance: Bartlebyian refusal, dilettantism, strategic negotiation, and reluctant conscription. This dissertation brings together sociological discourses of work, affect theory, and transnational American literature to hypothesize the rise of American Anglophone culture. The postwar crime novels of Raymond Chandler and Patricia Highsmith provide a genealogical origin for the decline of the welfare state through the deviant work of the hard-boiled detective or the international conman. Meanwhile, rejecting American triumphalism for dilettantism and espiocracy, the internationalism of Richard Yates and Paul Bowles enters downward states of depression and acedia that disrupt the suburban novel. The turn to internationalism necessitates a consideration of the centripetal movement of Cold War immigration. The contemporary novels of Susan Choi and Jhumpa Lahiri reappraise the ignored case of postwar Asian American knowledge workers, where political feelings of evasion and willfulness unsettle the sociological trope of the model minority. The case of the foreign student reveals that the immigrant body is shunted into racialized forms of both manual and reproductive labor under the pretext of knowledge work. Finally, post-9/11 finance novels of Pakistani writers Mohsin Hamid and H.M Naqvi harken back to postwar criminality by confronting the accusation of terroristic subjectivity through feelings of regret, precipitating a comprehensive exit from American work