Smith, Jonathan
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Computer and Systems Architecture
Digital Communications and Networking
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OS and Networks
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Digital Communications and Networking
Library and Information Science
OS and Networks
Software Engineering
Systems Architecture
Systems and Communications
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Publication MOSAIC: Multiple Overlay Selection and Intelligent Composition(2007-10-24) Loo, Boon Thau; Ives, Zachary G; Mao, Yun; Smith, Jonathan MToday, the most effective mechanism for remedying shortcomings of the Internet, or augmenting it with new networking capabilities, is to develop and deploy a new overlay network. This leads to the problem of multiple networking infrastructures, each with independent advantages, and each developed in isolation. A greatly preferable solution is to have a single infrastructure under which new overlays can be developed, deployed, selected, and combined according to application and administrator needs. MOSAIC is an extensible infrastructure that enables not only the specification of new overlay networks, but also dynamic selection and composition of such overlays. MOSAIC provides declarative networking: it uses a unified declarative language (Mozlog) and runtime system to enable specification of new overlay networks, as well as their composition in both the control and data planes. Importantly, it permits dynamic compositions with both existing overlay networks and legacy applications. This paper demonstrates the dynamic selection and composition capabilities of MOSAIC with a variety of declarative overlays: an indirection overlay that supports mobility (i3), a resilient overlay (RON), and a transport-layer proxy. Using a remarkably concise specification, MOSAIC provides the benefits of runtime composition to simultaneously deliver application-aware mobility, NAT traversal and reliability with low performance overhead, demonstrated with deployment and measurement on both a local cluster and the PlanetLab testbed.Publication Scalable Security Mechanisms for the Internet(2001-01-01) Keromytis, Angelos D.; Ioannidis, Sotiris; Greenwald, Michael B.; Smith, Jonathan MThe design principle of restricting local autonomy only where necessary for global robustness has led to a scalable Internet. Unfortunately, this scalability and capacity for distributed control has not been achieved in the mechanisms for specifying and enforcing security policies. The STRONGMAN system described in this paper demonstrates three new approaches to providing efficient local policy enforcement complying with global security policies. First is the use of a compliance checker to provide great local autonomy within the constraints of a global security policy. Second is a mechanism to compose policy rules into a coherent enforceable set, e.g., at the boundaries of two locally autonomous application domains. Third is the "lazy instantiation" of policies to reduce the amount of state enforcement points need to maintain. We demonstrate the use of these approaches in the design, implementation and measurements of a distributed firewall.Publication A Study of Cache-Based IP Flow Switching(2000-11-16) Ertugay, Osman; Smith, Jonathan MMeeting the service demands from QoS-based network applications is a very challenging task performed in many high-end routers and switches. This task involves management of resources like bandwidth and memory in network devices. The memory in the form of a very fast cache that instruments wire-speed classification, discrimination, and forwarding of network packets needs to be managed very effectively. We examine the management of a specific IP flow-cache architecture through simulations based on traffic traces collected from a campus intranet. A probabilistic cache install policy is examined over a range of cache sizes and install probabilities. This policy successfully identifies the flows that warrant caching and slightly improves deployable policies based on site-specific traffic information can increase the switching performance even higher.Publication End-Point Resource Admission Control for Remote Control Multimedia Applications(1995) Nahrstedt, Klara; Smith, Jonathan MOne goal in certain classes of networked multimedia applications, such as full-feedback remote control, is to provide end-to-end guarantees. To achieve guarantees, all resources along the path(s) between the resource(s) and sink(s) must be controlled. Resource availability is checked by the admission service during the call establishment phase. Current admission services control only network resources such as bandwidth and network delay. To provide end-to-end guarantees, the networked applications also need operation system resources and I/O devices at the endpoints. All such resources must be included in a robust admission process. By integrating the end-point resources, we observed several dependencies which force changes in admission algorithms designed and implemented for control of a single resource. We have designed and implemented the multi-level admission service within our Omega architecture which controls the availability of end-point resources needed in remote control multimedia applications such as telerobotics.Publication A Secure and Reliable Bootstrap Architecture(1996-12-02) Arbaugh, William A; Farber, David J; Smith, Jonathan MIn a computer system, the integrity of lower layers is treated as axiomatic by higher layers. Under the presumption that the hardware comprising the machine (the lowest layer) is valid, integrity of a layer can be guaranteed if and only if: (1) the integrity of the lower layers is checked, and (2) transitions to higher layers occur only after integrity checks on them are complete. The resulting integrity "chain" inductively guarantees system integrity. When these conditions are not met, as they typically are not in the bootstrapping (initialization) of a computer system, no integrity guarantees can be made. Yet, these guarantees are increasingly important to diverse applications such as Internet commerce, intrusion detection systems, and "active networks." In this paper, we describe the AEGIS architecture for initializing a computer system. It validates integrity at each layer transition in the bootstrap process. AEGIS also includes a recovery process for integrity check failures, and we show how this results in robust systems. We discuss our prototype implementation for the IBM personal computer (PC) architecture, and show that the cost of such system protection is surprisingly small.Publication Automated Recovery in a Secure Bootstrap Process(1997-08-01) Arbaugh, William A; Keromytis, Angelos D; Farber, David J; Smith, Jonathan MIntegrity is rarely a valid presupposition in much systems architecture, yet it is necessary to make any security guarantees. To address this problem, we have designed a secure bootstrap process, AEGIS, which presumes a minimal amount of integrity, and which we have prototyped on the Intel x86 architecture. The basic principle is sequencing the bootstrap process as a chain of progressively higher levels of abstraction, and requiring each layer to check a digital signature of the next layer before control is passed to it. A major design decision is the consequence of a failed integrity check. A simplistic strategy is to simply halt the bootstrap process. However, as we show in this paper, the AEGIS bootstrap process can be augmented with automated recovery procedures which preserve the security properties of AEGIS under the additional assumption of the availability of a trusted repository. We describe a variety of means by which such a repository can be implemented, and focus our attention on a network accessible repository. The recovery process is easily generalized to applications other than AEGIS, such as standardized desktop management and secure automated recovery of network elements such as routers or "Active Network" elements.Publication QuanTM: A Quantitative Trust Management System(2009-03-01) West, Andrew G; Aviv, Adam J; Chang, Jian; Prabhu, Vinayak S; Blaze, Matthew A; Kannan, Sampath; Lee, Insup; Smith, Jonathan M; Sokolsky, OlegQuantitative Trust Management (QTM) provides a dynamic interpretation of authorization policies for access control decisions based on upon evolving reputations of the entities involved. QuanTM, a QTM system, selectively combines elements from trust management and reputation management to create a novel method for policy evaluation. Trust management, while effective in managing access with delegated credentials (as in PolicyMaker and KeyNote), needs greater flexibility in handling situations of partial trust. Reputation management provides a means to quantify trust, but lacks delegation and policy enforcement. This paper reports on QuanTM’s design decisions and novel policy evaluation procedure. A representation of quantified trust relationships, the trust dependency graph, and a sample QuanTM application specific to the KeyNote trust management language, are also proposed.Publication Gigabit Networks(1996) Smith, Jonathan MThis chapter summarizes what we have learned in the past decade of research into extremely high throughput networks. Such networks are colloquially referred to as "Gigabit Networks" in reference to the billion bit per second throughput regime they now operate in. The engineering challenges are in the integration of fast transmission systems and high-performance engineering workstations.Publication Operating Systems Support for End-to-End Gbps Networking(1993-03-01) Smith, Jonathan M; Traw, C. Brendan SThis paper argues that workstation host interfaces and operating systems are a crucial element in achieving end-to-end Gbps bandwidths for applications in distributed environments. We describe several host interface architectures, discuss the interaction between the interface and host operating system, and report on an ATM host interface built at the University of Pennsylvania. Concurrently designing a host interface and software support allows careful balancing of hardware and software functions. Key ideas include use of buffer management techniques to reduce copying and scheduling data transfers using clocked interrupts. Clocked interrupts also aid with bandwidth allocation. Our interface can deliver a sustained 130 Mbps bandwidth to applications, roughly OC-3c link speed. Ninety-three percent of the host hardware subsystem throughput is delivered to the application with a small measured impact on other applications processing.Publication DHARMA: Distributed Home Agent for Robust Mobile Access(2005-03-13) Mao, Yun; Knutsson, Björn; Lu, Honghui; Smith, Jonathan MMobile wireless devices have intermittent connectivity, sometimes intentional. This is a problem for conventional Mobile IP, beyond its well-known routing inefficiencies and deployment issues. DHARMA selects a location-optimized instance from a distributed set of home agents to minimize routing overheads; set management and optimization are done using the PlanetLab overlay network. DHARMA's session support overcomes both transitions between home agent instances and intermittent connectivity. Cross-layer infomation sharing between the session layer and the overlay network are used to exploit multiple wireless links when available. The DHARMA prototype supports intermittently connected legacy TCP applications in a variety of scenarios and is largely portable across host operating systems. Experiments with DHARMA deployed on more than 200 PlanetLab nodes demonstrate routing performance consistently better than that for best-case Mobile IP.