Richard A. Rouil

Adaptive Channel Scanning for IEEE 802.16e

In this article we propose an adaptive algorithm that determines the duration and frequency of channel scanning in order to facilitate the discovery of neighboring base stations and handovers across multiple IEEE 802.16 networks. The proposed algorithm supports application quality of service requirements and can be generalized to multiple mobile devices concurrently performing channel scanning. Performance results for select simulation scenarios are presented and discussed

Performance Metrics for IEEE 802.21 Media Independent Handover (MIH) Signaling

The IEEE 802.21 Media Independent Handover (MIH) working group is developing a set of mechanisms to facilitate migration of mobile users between access networks that use different link-layer technologies. Among these are mobility managers that create and process signaling messages to facilitate handovers. The MIH signaling architecture being developed in the Internet Engineering Task Force (IETF) allows any transport layer protocol to carry MIH messages. The IETF has considered using the unreliable but lightweight transport available with the User Datagram Protocol (UDP) as well as the reliable stream-oriented transport with congestion control offered by the Transmission Control Protocol (TCP). In this paper we develop mathematical models that result in expressions for the characteristic function of the time required to complete exchanges of an arbitrary number of MIH signaling messages between a mobile node (MN) and a remote mobility manager (MM). Our models also provide expressions for the average amount of overhead associated with MIH message exchanges due to retransmissions either by the MIH signaling entities or by the transport-layer protocol. In addition, we provide simulation results that confirm the results from the mathematical model and illustrate the effect of varying transport parameters such as the TCP maximum retransmission timeout.

Using the Media Independent Information Service to Support Mobile Authentication in Fast Mobile IPv6

We explore the use of the Media Independent Information Service (MIIS) in the IEEE 802.21 Media Independent Handover (MIH) framework to improve handover performance for Fast Mobile IPv6 by providing Authentication information. We explore the tradeoffs of Pre-Authentication before joining a new network versus authentication after connecting to a new network during a Fast Mobile IPv6 handover. We discuss our implementations of services available from the MIIS in simulation using the ns-2 simulation system and evaluate their performance.

Media independent handover transport using cross-layer optimized stream control transmission protocol

The Media Independent Handover (MIH) architecture finalized by the IEEE 802.21 working group facilitates handovers between heterogeneous networks. The signaling messages exchanged between the network entities, namely Mobile Nodes (MNs) and Points of Service (PoSs) must be delivered in a timely and reliable manner. In this document, we analyze the current proposed solutions to transport MIH messages and review their limitations. We also propose an efficient solution using the Stream Control Transmission Protocol (SCTP). The solution uses SCTPs multihoming and multistreaming capabilities and is optimized by using the MIH services. We analyze the performance of the proposed solution for various packet loss conditions and loads.

Unsupervised anomaly detection system using next-generation router architecture

Unlike many intrusion detection systems that rely mostly on labeled training data, we propose a novel technique for anomaly detection based on unsupervised learning. We apply this technique to counter denial-of-service attacks. Initial simulation results suggest that significant improvements can be obtained. We discuss an implementation of our anomaly detection system in the ForCES router architecture and evaluate it using recorded attack traffic

Nationwide Safety: Nationwide Modeling for Broadband Network Services

As governments plan nationwide, interoperable broadband networks for their public safety services, the challenge arises of determining how and where to invest limited resources to meet demanding requirements. The United States is in the early stages of planning a nationwide 700-MHz long-term evolution (LTE) network for use by public safety officials at the local, state, and federal levels. This article presents a framework for the modeling and planning of a public safety broadband network on a nationwide scale. This framework addresses the challenges of modeling and planning for a country that is diverse in terms of terrain, user density, and public safety needs. It does so while managing computational complexity so that alternate scenarios (e.g., target areas, user requirements, and site assumptions) can be readily assessed in a timely fashion. The approach utilizes a clustering algorithm to classify areas by their terrain characteristics and user population, an iterative process for sampling and analyzing areas within each cluster, and extrapolation of the results to generate nationwide statistics such as site count, coverage percentage, and network load. Examples are given that illustrate the implications of stringent coverage reliability requirements as well as the impact of high traffic density resulting from an incident response.

An analysis of path recovery schemes in GMPLS optical networks with various levels of pre-provisioning

The amount of resource provisioning prior to failure events to support optical path recovery has a significant impact on network performance, and so designing recovery mechanisms for any large network necessitates balancing multiple (in some cases, competing) requirements. The Common Control and Measurement Plane (CCAMP) working groups Protection and Restoration Design Team conducted a qualitative analysis of path protection schemes using different degrees of backup resource pre-provisioning. The resulting analysis grid highlights some of the trade-offs between the different approaches. In this paper, we describe the results of a simulation study that we conducted using the NIST GMPLS/Lightwave Agile Switching Simulator (GLASS) simulation tool. By measuring network performance with respect to the metrics used by the design team, we were able to produce quantitative results that confirm the design teams qualitative analysis and provide additional information for carriers and service providers who are designing optical networks.

Optimizing Authentication in Media Independent Handovers Using IEEE 802.21

In this paper we study the performance of the authentication process in media independent handovers and consider the impact of using IEEE 802.21 link triggers to achieve seamless mobility. We describe all interactions between the 802.21 services and the authentication in order to achieve timely and seamless handovers.

Measuring the resiliency of cellular base station deployments

The National Public Safety Telecommunications Council (NPSTC) has defined resiliency as the ability of a network to withstand the loss of assets and to recover quickly from such losses. How to measure the resiliency of a base station deployment is an important consideration for network planners and operators. In this paper, we propose a resiliency measurement method in conjunction with a performance metric such as coverage or supported throughput, where we define the resiliency as the maximum number of sites that can fail before the metric falls below a minimum acceptable threshold. Because the number of combinations of failures increases exponentially with respect to the number of sites in a given deployment, we introduce an algorithm that generates estimates of the lowest, highest, and average values of the metric for a given failure count while examining a subset of the possible failure combinations. We use an example deployment to demonstrate how the resiliency metric can be used to identify sites that have a disproportionate impact on performance; the network planner can harden these sites or, for a future deployment, adjust the site placement to reduce the effect of the high-impact sites.

IEEE 802.21 transport solution using cross-layer optimized Stream Control Transmission Protocol

The media independent handover (MIH) architecture is designed to facilitate the signaling and enable seamless handovers in heterogeneous networks. In this paper, we propose a solution using the stream control transmission protocol (SCTP) to efficiently carry MIH messages. The solution uses SCTPpsilas multihoming and multistreaming capabilities along with cross-layer information available through the MIH. We analyze the performance of the proposed solution for various packet loss conditions.