Packet encapsulation is a general network technique that provides an essential building block for constructing secure networks. While extensively used in IP networks over the last few decades, secure packet encapsulation remains largely unexplored in the context of Named Data Networking (NDN) networks. NDN represents a radical departure from traditional endpoint-oriented networking by making secured data the centerpiece of communication. This new data-centric design brings both advantages and new challenges for the development of secure packet encapsulation that can preserve essential properties of an NDN network, including in-network data caching and builtin multicast data delivery. In this paper, we first identify the major differences between encapsulation solution designs in IP and NDN, highlighting the ensuing challenges, both inherent and practical. We then present a novel design to achieve secure NDN data packet encapsulation, and showcase an implementation suite that enables efficient fetching of securely encapsulated data.11The views, opinions and/or findings expressed are those of the authors and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government. Distribution Statement “A” (Approved for Public Release, Distribution Unlimited)

In this paper we explore solutions to robust group communication in disadvantaged wireless networks that exhibit low bandwidth, high packet losses, and frequent or even permanent network partitions. More specifically, we propose a group communication protocol based on Named Data Networking (NDN). By design, NDN’s in-network caching and stateful forwarding plane can help improve data delivery robustness in disadvantaged networks, but when content is generated with dynamic rates, an efficient, low-overhead synchronization protocol is needed to inform group members to fetch newly generated content promptly. In this paper, we describe the Prefetch Loss-Insensitive Sync (PLI-Sync) protocol for group communication in highly disadvantaged networks. PLI-Sync combines optimistic content pre-fetching with new content notification via sync, and addresses the challenges of how to distinguish wireless packet losses from mobility-induced disconnections, and between data availability and retrievability. Our evaluations show that leveraging the interplay between optimistic pre-fetching and a low rate sync protocol can significantly reduce communication overhead compared to relying on sync protocols alone, while maintaining low data fetching latency and robust delivery in a variety of wireless conditions and traffic load settings.

Optimizations in wireless ad-hoc network control protocols, such as shortest path routing and reduced topology set operations, are widely employed and recognized to decrease overhead and improve performance in benign conditions. Such optimizations, however, result in vulnerabilities that can decrease the robustness of the network when misconfigured, and can be readily exploited under various adversarial models. In this paper, we study the effects of such optimizations in the presence of misconfiguration and attacks, and we propose an Attack-Resistant Routing (ARR) framework that mitigates adversarial effects. While many other methods of combating certain control plane attacks have been proposed, our method is unique in that it assumes no prior knowledge of the mechanisms used to effect the attacks and the type of misinformation affecting the network. Rather, it alleviates the vulnerabilities introduced by various optimizations, thus increasing network robustness when the network is under attack or misconfigured. We show that ARR can withstand multiple and severe attacks and restore network performance to levels close to normal.

Traffic anomaly detection is primarily concerned with identifying malicious traffic patterns in a much larger stream of benign traffic. Traditionally, this is achieved by selecting a very specialized set of traffic-based features that are used for both training a model, as well as for detection at runtime. This paper introduces a novel method of anomaly detection that breaks the assumption that the same set of features should be used for both training and runtime detection. Building upon the concept of Learning Using Privileged Information (LUPI), this paper shows how to build a detection model that uses an extended set of features, some that are available only during training, and some also available at runtime, with results significantly superior to the traditional learning methods. We demonstrate the usage of the privileged features in detecting malicious botnet activities in a network, activities shown to be challenging to detect in past works.

Live virtual machine (VM) migration is commonly used for enabling dynamic resource or fault management, or for load balancing in datacenters or cloud platforms. A service hosted by a VM may also be migrated to prevent its visibility to an external adversary who may seek to disrupt its operation by launching a DDoS attack against it. We first show that current systems cannot adequately hide a VM migration from an external adversary. The key reason for this is that a migration typically manifests a traffic pattern with distinguishable statistical properties. We introduce two new attacks that can allow an adversary to effectively track a migration in progress, by leveraging observations of these properties. As our primary contribution, we design and implement a stealth migration framework that causes migration traffic to be indistinguishable from regular Internet traffic, with a negligible latency overhead of approximately 0.37 seconds, on average.

We describe a system for estimating the reliability of nodes in a mobile ad hoc network. The goal of the system is to detect insider attacks on the control plane of wireless protocols at the link and network layers, and to generate and propagate corresponding reliability estimates for nodes across the network. Our contributions are two-fold: first, we implement a cross-layer invariant-based technique for attack detection, where rules about correct combined behavior of protocols are specified based on data collected from multiple layers of the protocol stack. Next, we use the results of our attack detection techniques to compute reliability estimates for network nodes, where a reliability estimate represents the estimate of a node N for another node M. The form of our reliability estimate for a node is expressed as (t, c), where t indicates the trust for that node, and c indicates the confidence in this trust value. Reliability estimates are propagated across the network in a manner that is resilient to malicious nodes that propagate false reliability estimates, and minimizes network overheads. Our simulation results show that the above techniques result in highly accurate reliability estimates even in the presence of multiple malicious nodes in the network.

In this paper, we discuss a time synchronization approach to the time divergence problem in hybrid network emulation. Such emulation comprises primarily a discrete-event simulated network and virtual machines that send and receive traffic through the simulated network. For slower than real-time network simulations, the rate of time advance on virtual machines (real time) is faster than that of the discrete-event time. Consequently, packet transmission latency and other metrics in such hybrid network emulations will be distorted. As a result, e.g., TCP sessions between virtual machines may unduly time out. To address this problem, we have developed TimeSync, which tracks discrete-event simulation time to control time advance on virtual machines for slower than real time simulations so that time perception in the hybrid network emulation system is synchronized. We describe how TimeSync works and present our experimental evaluation and analysis.

Due to its obvious importance, fault detection and localization is a well-studied problem in communication networks, as attested by the many techniques designed to address this problem. The inherent variability, limited component reliability, and constrained resources of MANETs (Mobile Ad hoc Networks) make the problem not just more important, but also critical. Practical development and deployment considerations imply that fault detection and localization methods must i) avoid relying on overly detailed models of network protocols and traffic assumptions and instead rely on actual cross-layer measurements/observations, and ii) be applicable across different network scales and topologies with minimum adjustments. This paper demonstrates the feasibility of such goals, and proposes an important and as yet unexplored approach to fault management in MANETs: network-invariant fault detection, localization and diagnosis with limited knowledge of the underlying network and traffic models. We show how fault management methods can be derived by observing statistical network/traffic measurements in one network, and subsequently applied to other networks with satisfactory performance. We demonstrate that a carefully designed but widely applicable set of local and weak global indicators of faults can be efficiently aggregated to produce highly sensitive and specific methods that perform well when applied to MANETs with varying sizes, topologies, and traffic matrices.

Virtual Ad Hoc Network (VAN) testbed aims at achieving large scale application testing for ad hoc networks by integrating host virtualization and network simulation. Efficient use of storage space is essential for such testbeds. Storage redundancy resulting from duplicated files and application installations across the virtual machines in a large scale testbed (> a few hundred VMs) can be significantly reduced by using storage sharing techniques. Although Content Addressable Storage (CAS) along with Copy-on-write can remove storage redundancy at block-level, it requires hash computation for every write operation that incurs considerable online computation overhead.

Testing and evaluation of applications over mobile ad hoc networks is a challenge due to the difficulty of conducting field experiments and regression test. The common practice today is to perform such testing in a virtual ad hoc network testbed before field experiments. Although typical emulated network testbeds can be instrumented to generate and control certain network conditions, there is a class of network-aware applications, including network management systems, that needs to interact with network elements in order to observe and control the network behavior. To support testing and evaluation of such applications, a virtual ad hoc network testbed must allow monitoring as well as runtime configuration and control of the virtual network. Moreover, such virtual network testbeds should i) present a standard-based interface, ii) streamline the testbed setup process, and iii) not require any code modification to the application under test. In this paper, we present techniques that can satisfy the above requirements for a virtual ad hoc network testbed. An SNMP interface was used to illustrate the automation of testbed setup for evaluating applications as is.

For a complex distributed system to be dependable, it must be continuously monitored, so that its failures and imperfections can be discovered and corrected in a timely manner. This work is concerned with the monitoring of large, open and heterogeneous systems, at their application level. Our object

The construction and maintenance of large and complex software systems depend on the existence of global principles describing the structure and the interaction among its various components. Due to their critical nature, such principles have to be explicitly formulated and strictly verified and enforced throughout the lifetime of the software product. Aspect Oriented Software Development (AOSD) provides necessary tools for the formulation of such principles as aspects--called here structural aspects, and for their compile-time verification and dynamic enforcement. This enforcement, however, becomes problematic when aspects are also used as a vehicle for programming the components themselves, due to aspect interference. In this paper we show how the aspects embedded in system's components--called here programming aspects--can interact unfavourably with other components thus invalidating the role of the structural aspects. We present a number of methods that address this problem, and we introduce a DirectedPairWiseWeaver tool we have developed in order to prevent this interference.

One of the most important challenges facing the builders of enterprise software is the reliable implementation of the policies that are supposed to govern the various communities operating within an enterprise. Such policies are widely considered fundamental to enterprise modeling, and their specification were the subject of several recent investigations. But specification of the policy that is to govern a given community is only the first step towards its implementation; the second, and more critical step is to ensure that all members of the community actually conform to the specified policy. The conventional approach to the implementation of a policy is to build it into all members of the community subject to it. But if the community in question is large and heterogeneous, and if its members are dispersed throughout a distributed enterprise, then such "manual" implementation of its policy would be too laborious and error-prone to be practical. Moreover, a policy implemented in this manual manner would be very unstable with respect to the evolution of the system, because it can be violated by a change in the code of any member of community subject to it. It is our thesis that the only reliable way for ensuring that an heterogeneous distributed community of software modules and people conforms to a given policy is for this policy to be strictly enforced. A mechanism for establishing enterprise communities by formally specifying their policies, and by having these policies enforced is the subject of the paper.