Secure reporting of traffic forwarding activity in mobile ad hoc networks
Nodes forward data on behalf of each other in mobile ad hoc networks. In a civilian application, nodes are assumed to be selfish and rational, i.e., they pursue their own self-interest. Hence, the ability to accurately measure traffic forwarding is critical to ensure proper network operation. These measurements are often used to credit nodes based on their level of participation, or to detect loss. Past solutions employ neighbor monitoring and reporting on node forwarding traffic. These methods are not applicable in civilian networks where neighbor nodes lack the desire or ability to perform the monitoring function. Such environments occur frequently in which neighbor hosts are resource constrained, or in networks where directional antennas are used and reliable monitoring is difficult or impossible. In this paper, we propose a protocol that uses nodes on the data path to securely produce packet forwarding reports. Reporting nodes are chosen randomly and secretly so that malicious nodes cannot modify their behavior based upon the monitoring point. The integrity and authenticity of reports are preserved through the use of secure link layer acknowledgments and monitoring reports. The robustness of the reporting mechanism is strengthened by forwarding the report to multiple destinations (source and destination). We explore the security, cost, and accuracy of our protocol.

title: Mobile multi-layered IPsec
abstract: To achieve high throughput in wireless networks, smart forwarding and processing of packets in access routers is critical for overcoming the effects of the wireless links. However, these services cannot be provided if data sessions are protected using end-to-end encryption as with IPsec, because the information needed by these algorithms resides inside the portion of the packet that is encrypted, and can therefore not be used by the access routers. A previously proposed protocol, called Multi-layered IPsec (ML-IPsec) modifies IPsec in a way so that certain portions of the datagram may be exposed to intermediate network elements, enabling these elements to provide performance enhancements. In this paper we extend ML-IPsec to deal with mobility and make it suitable for wireless networks. We define and implement an efficient key distribution protocol to enable fast ML-IPsec session initialization, and two mobility protocols that are compatible with Mobile IP and maintain ML-IPsec sessions. Our measurements show that, depending on the mobility protocol chosen, integrated Mobile IP/ML-IPsec handoffs result in a pause of 53–100 milliseconds, of which only 28–75 milliseconds may be attributed to ML-IPsec. Further, we provide detailed discussion and performance measurements of our MML-IPsec implementation. We find the resulting protocol, when coupled with SNOOP, greatly increases throughput over scenarios using standard TCP over IPsec (165% on average). By profiling the MML-IPsec implementation, we determine the bottleneck to be sending packets over the wireless link. In addition, we propose and implement an extension to MML-IPsec, called dynamic MML-IPsec, in which a flow may switch between plaintext, IPsec and MML-IPsec. Using dynamic MML-IPsec, we can balance the tradeoff between performance and security.

title: Restoration in IP over WDM optical networks
abstract: An important requirement in any high speed network is to ensure the network's survivability, i.e., the ability to provide reroutes of ongoing connections after the failure of network components. We consider the problem of embedding an IP layer topology in the WDM transport network layer with the objective of achieving the network's survivability in the IP layer. Specifically, we consider the problem of embedding an arbitrary IP layer topology in a WDM wavelength-routing ring network such that the IP topology remains connected under the presence of the failure of any link in the WDM layer.

title: Efficient route establishment and maintenance in wireless sensor networks with mobile base stations
abstract: The integration of ground wireless adhoc networks and airborne UAVs is a promising solution for realtime data collection in wireless sensor networks. Such networks play a vital role in many mission critical tasks such as forest fire-fighting and battlefield support. An important problem is to establish/maintain efficient routing structures in the ground sensor network for packet relaying. Our problem is unique in that the base stations are non-static, which necessitates frequent update of the routing structure. The performance of flooding based methods are evaluated. Particularly, in order to deal with non-uniform node density, we propose to introduce an artificial delay factor to control the flooding pattern. We mathematically prove that the delay should be proportional to local node density. Our simulation results show that the proposed method achieves good load balance among multiple base stations.

title: Analyzing the Performance of Mesh and Fat-Tree Topologies for Network on Chip Design
abstract: The demand of integration of many heterogeneous semiconductor intellectual property (IP) blocks has been introducing a new chip design paradigm so called on chip network. This paradigm promisingly offers a packet switched network among IPs to reduce the main problems in the very deep sub micron technologies that arise from non-scalable global wire delay, failure to achieve global synchronization, errors due to the signal integrity, non-scalable bus based functional interconnection, etc. This paper introduces interconnected or switched network topologies and also analyze their performances in terms of communication protocol related to the issues such as routing strategy, buffer size, routing algorithm , etc. The above mentioned evaluations are done by utilizing the tool that has been widely used in the research domain of computer network design, so called NS-2.

title: On the all-to-all broadcast problem in optical networks
abstract: This paper considers the transmission of uniform deterministic traffic in an optical broadcast-star network using wavelength division multiplexing. Lower bounds are established on the minimum time to exchange information between every node pair in such a network with tunable transmitters and fixed-tuned receivers. Three different scheduling algorithms are developed that are strictly optimal in three regimes of system parameters. The results are applicable to arbitrary tuning delays and arbitrary numbers of wavelength channels, and indicate the existence of a well-defined transition regime from tuning-limited operation to bandwidth-limited operation.

title: Packet filtering for congestion control under DoS attacks
abstract: Congestion control in IP networks is typically done at each router through queue management, and the network is entirely dependent on the end hosts to react congestion. However, when misbehaving flows exist and continue to send their packets in very high rates, the queue management schemes implemented in current IP routers reveal a significant shortcoming in protecting legitimate flows. Here, we propose a novel scheme for congestion control in IP networks. Our approach is a time-window based filtering mechanism implemented in a router and processed before a queue management policy is applied. Setting the window size properly and dropping packets reaching in the next window can catch the nonresponsive nature of misbehaving flows. The performance of our proposed scheme is demonstrated through extensive simulations using the NS2, simulator using a set of simulated traffic generated based on IP traces reported in http://www.nlnar.org.