-
[show abstract]
[hide abstract]
ABSTRACT: The current TCG architecture suffers from the time-of-check-to-time-of-use (TOCTOU) attacks in commodity PC operating systems (OS), in which kernel rootkits can get unrestricted access to OS resources. VMM-based approaches running at a privilege level higher than that of virtual machine (VM) kernel can effectively detect dynamic or static data attacks occurring in VMs. This paper proposes a lightweight response mechanism (LWRM) for TCG TOCTOU attacks occurring in VMs. LWRM has the following features: (1) compared to the existing response mechanism, LWRM is more effective in defeating the TCG TOCTOU attacks; (2) LWRM imposes less overhead on the system during normal execution; (3) LWRM is transparent to the kernel rootkits; and (4) LWRM can work in the scenarios with more than one run-time trusted virtual machine. We describe the design idea and the implementation by using the Xen virtual machine monitor (VMM) and the virtual TPM facility shipped with the Xen.
Performance Computing and Communications Conference (IPCCC), 2009 IEEE 28th International; 01/2010
-
28th International Performance Computing and Communications Conference, IPCCC 2009, 14-16 December 2009, Phoenix, Arizona, USA; 01/2009
-
[show abstract]
[hide abstract]
ABSTRACT: Interrupt coalescing (IC) technique has been used in general-purpose operating systems to mitigate receive livelock (RL) problem in gigabit Ethernet network hosts. Schemes for dynamically tuning the interrupt coalescing behavior of a communication interface based on traffic load or system state have been proposed. However, all the existing IC schemes are designed using heuristics. In this paper we present an analytical model for the IC technique and carry out a detailed study of existing IC schemes in terms of their performance characteristics including system goodput, CPU consumption and latency. We validate our analysis through measurement-based experiments.
Communications, 2008. ICC '08. IEEE International Conference on; 06/2008
-
Proceedings of IEEE International Conference on Communications, ICC 2008, Beijing, China, 19-23 May 2008; 01/2008
-
[show abstract]
[hide abstract]
ABSTRACT: Studies of the performance of interrupt-driven operating systems in high-speed networks have brought forth the problem of receive livelock. Device hybrid interrupt-polling and interrupt coalescing are two common techniques used in general-purpose operating systems to mitigate this problem. Adaptive schemes based on local knowledge have been proposed for each technique above. However, all the schemes proposed so far are designed using heuristics. In addition, the capabilities of the proposed schemes have not been systematically compared. In this paper, we first analyze the capabilities of these schemes by investigating the relationship between key system parameters and system goodput in different packet protocol processing modes under heavy traffic load. Then we propose a robust device hybrid interrupt-polling (RHIP) scheme which achieves high system goodput, low packet loss and good latency with low consumption of CPU cycles, compared to other schemes. The key idea of RHIP is to use the recipient's buffer information to adjust the interrupt rate and the protocol processing time. We validate our analysis and design through several experiments.
Local Computer Networks, 2007. LCN 2007. 32nd IEEE Conference on; 11/2007
-
[show abstract]
[hide abstract]
ABSTRACT: Gigabit Ethernet is now finding wider deployment in computer networks. The conventional operating system suffers from the receive livelock problem in Gigabit Ethernet networks. The device hybrid (interrupt + polling) scheme has been widely used to overcome this problem in current operating systems such as GNU/Linux and FreeBSD. However, controlling the polling time without regard to the system state can degrade the ability of a hybrid scheme in some situations. This paper focuses on the system performance of the operating systems that employ the device hybrid scheme in kernel space. A queue-based adaptive polling (QAPolling) scheme is introduced that: (1) significantly improves system goodput and reduces packet loss over a wide range of computer hardware configurations and traffic conditions, (2) is scalable and easily deployed. The key idea behind QAPolling is to adjust the polling time adaptively according to the information of the application receiving queues, which are in kernel space and change with the system state, instead of the packet arrival rate. We validate our design through experimental results in Gigabit Ethernet networks.
Performance, Computing, and Communications Conference, 2007. IPCCC 2007. IEEE Internationa; 05/2007
-
Proceedings of the 26th IEEE International Performance Computing and Communications Conference, IPCCC 2007, April 11-13, 2007, New Orleans, Louisiana, USA; 01/2007
-
[show abstract]
[hide abstract]
ABSTRACT: Achieving fair bandwidth distribution among uplink and downlink flows in the infrastructure based wireless local area networks (WLAN) which the distributed coordination function (DCF) mode is difficult. In this paper we present a new control theoretic approach to achieve a fair bandwidth distribution among the flows regardless of the transport protocol used by the flows. In addition, we explore methods to improve the channel bandwidth utilization and reduce the delay while improving the fair distribution. Our approach combines an AQM scheme for IFQ queue and the MAC layer design to achieve this goal. The effectiveness of our approach is demonstrated through extensive simulations over a wide range of network scenarios
Performance, Computing, and Communications Conference, 2006. IPCCC 2006. 25th IEEE International; 05/2006
-
Proceedings of the 25th IEEE International Performance Computing and Communications Conference, IPCCC 2006, April 10-12, 2006, Phoenix, Arizona, USA; 01/2006
-
[show abstract]
[hide abstract]
ABSTRACT: Active queue management (AQM) mechanisms are designed to provide better support for end-to-end congestion control mechanisms of transmission control protocol (TCP) in TCP/IP networks. This paper introduces a stable queue-based adaptive proportional–integral (Q-SAPI) controller for AQM and presents an implementation. The starting points of our approach are the recently developed fluid-flow modeling and control theoretic interpretation of the TCP/AQM dynamics, and the recently developed fixed-gain proportional–integral (PI) controller for AQM. Q-SAPI aims to improve the transient performance of the fixed-gain PI controller while maintaining its steady-state performance over a wide range of uncertainties in round-trip time (RTT) and the number of active TCP flows. The robustness of Q-SAPI is studied in detail, which provides guidelines for selecting control parameters. Through extensive simulations, we demonstrate the ability of Q-SAPI in controlling queue length in both transient and steady states. Q-SAPI achieves this by adapting the controller gains according to the queue length.
Computer Networks. 01/2006;
-
[show abstract]
[hide abstract]
ABSTRACT: In this paper, we consider two fairness problems (downlink/uplink fairness and fairness among flows in the same direction) that arise in the infrastructure WLAN. We propose a virtual queue management approach, named VQ-RED to address the fairness problems. We demonstrate the effectiveness of our approach by conducting a series of simulations. The results show that compared with standard DCF, VQRED not only greatly improves the fairness, but also reduces packet delays.
Local Computer Networks, 2005. 30th Anniversary. The IEEE Conference on; 12/2005
-
[show abstract]
[hide abstract]
ABSTRACT: The assured forwarding (AF) based service in a differentiated services (DiffServ) network fails to provide bandwidth assurance among competing aggregates under certain conditions, for example, where there exists a large disparity in the round-trip times, packet sizes, or target rates of the aggregates, or there exist non-adaptive aggregates. Several mechanisms have been proposed in order to address the problem of providing bandwidth assurance for aggregates, using only the knowledge gathered at ingress routers. In this paper, we present a control theoretic approach to analyze these mechanisms and explore the reasons when they fail to achieve bandwidth assurance under some circumstances. Then we propose a simple but robust controller for this problem, namely, the variable-structure adaptive CIR threshold (VS-ACT) mechanism. We validate the analysis and demonstrate that VS-ACT outperforms several other mechanisms proposed in the literature over a wide range of network dynamics through extensive simulations.
Computer Networks. 01/2005;
-
Proceedings of the 24th IEEE International Performance Computing and Communications Conference, IPCCC 2005, April 7-9, 2005, Phoenix, Arizona, USA; 01/2005
-
30th Annual IEEE Conference on Local Computer Networks (LCN 2005), 15-17 November 2005, Sydney, Australia, Proceedings; 01/2005
-
[show abstract]
[hide abstract]
ABSTRACT: In this paper a simple robust proportional-integral (R-PI) controller is proposed for active queue management (AQM). We assume that TCP/AQM dynamics can be described by the linearized TCP/AQM model (C. V. Hollot et al., April 2001). R-PI aims to address the tradeoff between responsiveness and stability and the tradeoff between responsiveness and high link utilization over a large range of structured and unstructured uncertainties. This controller achieves these goals by varying its control parameters according to the system state. We show that the closed-loop system is asymptotically stable as long as the control parameters are time-invariant and varying in a range. Extensive simulation results demonstrate the robust ability of R-PI compared with some other AQM mechanisms in the literature.
Communications, 2004 IEEE International Conference on; 07/2004
-
[show abstract]
[hide abstract]
ABSTRACT: The assured forwarding (AF) based service in a differentiated services (Diffserv) network fails to provide bandwidth assurance to aggregates in some circumstances. Several intelligent marking mechanisms have been proposed in the literature to improve bandwidth assurance for aggregates using the knowledge gathered at the ingress nodes. In this paper, we apply a control theoretic approach to this problem. We design a nonlinear proportional-integral (NPI) controller, called NPI-ACT, for adapting the CIR threshold. Performance results using extensive simulations demonstrate significant improvement using NPI-ACT in achieving bandwidth assurance over a wide range of network conditions compared to earlier mechanisms proposed in the literature.
Performance, Computing, and Communications, 2004 IEEE International Conference on; 02/2004
-
[show abstract]
[hide abstract]
ABSTRACT: Recent research studies have shown that assured forwarding (AF) service in the current differentiated services (Diffserv) framework does not provide bandwidth assurance in some circumstances. This paper proposes an adaptive marking threshold mechanism, called adaptive CIR threshold (ACT), which aims to improve bandwidth assurance for aggregate flows sharing the same AF class only based on local knowledge. Extensive simulation results demonstrate significant improvement with ACT in bandwidth assurance under various conditions: different round trip times (RTT), different numbers of micro-flows in an aggregate, different target rates, different packet sizes, and the presence of non-adaptive flows, compared with earlier mechanisms proposed in the literature.
Global Telecommunications Conference, 2003. GLOBECOM '03. IEEE; 01/2004
-
[show abstract]
[hide abstract]
ABSTRACT: Recent research studies have shown that assured forwarding (AF) service in the current differentiated services (Diffserv) framework does not provide bandwidth assurance in some circumstances. This paper proposes a mechanism, called Adaptive CIR+PIR Threshold (ACPT), which improves bandwidth assurance and domain throughput simultaneously. Extensive simulation results demonstrate significant improvement with ACPT in bandwidth assurance and domain throughput under various conditions: different round trip times (RTT), different numbers of micro-flows in an aggregate, different target rates, different packet sizes, and the presence of nonadaptive flows, compared to other mechanisms proposed in the literature.
Computer Communications and Networks, 2003. ICCCN 2003. Proceedings. The 12th International Conference on; 11/2003
-
[show abstract]
[hide abstract]
ABSTRACT: Virtualization technologies have been explored to mitigate the vulnerabilities in the current TCG architecture. But only a small number of efforts address the handling of the detected TCG TOCTOU attacks. This paper aims to defeat TCG TOCTOU attacks occurring in Xen hardware virtual machines. We propose an efficient response approach (ERA) in the environment of the Xen virtual machine monitor and the virtual TPM facility shipped with the Xen. ERA has the following features: (1) Effective in defeating the TCG TOCTOU attacks; (2) Impose less overhead on the system during normal execution; and (3) Transparent to guest virtual machines. We describe the ERA implementation in detail and evaluate its ability via experiments.
Multimedia Information Networking and Security, International Conference on.
