Anthony J. McAuley

AMRoute: ad hoc multicast routing protocol

The Ad hoc Multicast Routing protocol (AMRoute) presents a novel approach for robust IP Multicast in mobile ad hoc networks by exploiting user-multicast trees and dynamic logical cores. It creates a bidirectional, shared tree for data distribution using only group senders and receivers as tree nodes. Unicast tunnels are used as tree links to connect neighbors on the user-multicast tree. Thus, AMRoute does not need to be supported by network nodes that are not interested/capable of multicast, and group state cost is incurred only by group senders and receivers. Also, the use of tunnels as tree links implies that tree structure does not need to change even in case of a dynamic network topology, which reduces the signaling traffic and packet loss. Thus AMRoute does not need to track network dynamics; the underlying unicast protocol is solely responsible for this function. AMRoute does not require a specific unicast routing protocol; therefore, it can operate seamlessly over separate domains with different unicast protocols. Certain tree nodes are designated by AMRoute as logical cores, and are responsible for initiating and managing the signaling component of AMRoute, such as detection of group members and tree setup. Logical cores differ significantly from those in CBT and PIM-SM, since they are not a central point for data distribution and can migrate dynamically among member nodes. Simulation results (using ns-2) demonstrate that AMRoute signaling traffic remains at relatively low level for typical group sizes. The results also indicate that group members receive a high proportion of data multicast by senders, even in the case of a highly dynamic network.

Reliable broadband communication using a burst erasure correcting code

Traditionally, a transport protocol corrects errors in a computer communication network using a simple ARQ protocol. With the arrival of broadband networks, forward error correction is desirable as a complement to ARQ. This paper describes a simplified Reed-Solomon erasure correction coder architecture, adapted for congestion loss in a broadband network. Simulations predict it can both encode and decode at rates up to 1 gigabit per second in a custom 1 micron CMOS VLSI chip.

IDMP-based fast handoffs and paging in IP-based 4G mobile networks

We consider the use of our previously proposed Intra-Domain Mobility Management Protocol (IDMP) in fourth-generation mobile networks. On evaluating the heterogeneous access technologies, cellular layouts, and application characteristics of 4G environments, we realize a need to reduce both handoff latency and the frequency of mobility-related signaling. We first present IDMPs fast intradomain handoff mechanism that uses a duration-limited proactive packet multicasting solution. We quantify the expected buffering requirements of our proposed multicasting scheme for typical 4G network characteristics and compare it with alternative IP-based fast handoff solutions. We also present a paging scheme under IDMP that replicates the current cellular paging structure. Our paging mechanism supports generic paging strategies and can significantly reduce the mobility-related IP signaling load.

Autoconfiguration, registration, and mobility management for pervasive computing

In the vision of pervasive computing, users will exchange information and control their environments from anywhere using various wireline/wireless networks and computing devices. We believe that current protocols, such as DHCP, PPP, and Mobile IP, must be enhanced to support pervasive network access. In particular, this article identifies three fundamental functions: autoconfiguration, registration, and mobility management, that need such enhancements. Realizing that the IP autoconfiguration capabilities must be extended to configure routers and large dynamic networks, we first describe our autoconfiguration solution based on the dynamic configuration and distribution protocol (DCDP). Second, we discuss why providing user-specific services over a common infrastructure needs a uniform registration protocol, independent of the mobility and configuration mechanisms. We present an initial version of the basic user registration protocol (BURP), which provides secure client-network registration and interfaces to AAA protocols such as Diameter. Finally, we discuss the dynamic mobility agent (DMA) architecture, which provides a hierarchical and scalable mobility management framework. The DMA approach allows individual users to customize their own mobility-related features, such as paging, fast handoffs, and QoS support, over a common access infrastructure and to select multiple global binding protocols as appropriate.

IDMP: an intradomain mobility management protocol for next-generation wireless networks

This article describes a lightweight intradomain mobility management protocol (IDMP) for managing mobility within a domain, commonly known as micromobility management, for next-generation wireless networks. IDMP is modular and simple because it leverages existing protocols, such as Mobile IP or SIP as global mobility management, for locating roaming nodes. Unlike other proposed intradomain mobility management schemes, IDMP uses two dynamically auto-configured care-of addresses for routing the packets destined to mobile nodes. The global care-of address is relatively stable and identifies the mobile nodes attachment to the current domain, while the local care-of address changes every time the mobile changes subnets and identifies the mobiles attachment to the subnet level granularity. After describing the lightweight base protocol, we discuss possible enhancements to reduce the latency of intradomain updates during handoffs, which are critical for real-time applications both for wide area cellular networks and enterprise wireless LANs. We also discuss mechanisms to incorporate paging support in IDMP and hence reduce the mobility-related signaling load on a mobile node. Detailed implementation and performance results from experiments on our testbed are also presented.

Self-configuring networks

To make future tactical battlefield networks more flexible and robust, nodes must rapidly configure themselves with little or no human intervention and reconfigure automatically as the environment changes. This paper describes the dynamic registration and configuration protocol (DRCP) and dynamic address allocation protocol (DAAP) that together can provide true stateless autoconfiguration of an entire network domain. We first describe DRCP which extends DHCP into new domains such as wireless networks and commercial service providers. We then describe DAAP, which distributes addresses and other configuration parameters to DRCP servers. Although kept much simpler by relying on DRCP we show DAAP must still be carefully designed to ensure robustness while maintaining enough address hierarchy to reduce routing protocol overhead. Implementations of DRCP and DAAP on a Linux PC platform are described.

MarconiNet supporting streaming media over localized wireless multicast

Flexible multi-media streaming such as advertisment insertion, location based services, mobility and wireless access are vital components that make existing Internet Radio and TV networks more attractive for the roaming users. All of these applications also provide added value to telematics, and military usage including coordination, education, situation awareness, distributed simulation, battlefield communication and multi-player games. While content distribution over a wired network can be realized by instituting proxies and gateways at several parts of the access network, providing mobility over heterogeneous wireless access need to consider many operational issues such as handoff, join and leave latency and desired level of quality of service for the mobile clients. This paper discusses some novel application layer techniques that provide a platform for Mobile E-Commerce with a multi-tiered payment and security scheme that supports a business model for a global streaming network. The proposed streaming network called MarconiNet is based on standard IETF protocols such as SIP, SAP and SDP for signaling, RTSP for stream control and RTP/RTCP for media delivery and feedback control.

Dynamic service negotiation protocol (DSNP) and wireless DiffServ

This paper presents the design principles of dynamic service negotiation protocol (DSNP). DSNP is a protocol to negotiate the SLS (service level specification) in the IP layer. It can be used for service negotiation from host to network, network to host, and network to network. The automated negotiation makes service negotiation efficient in terms of time, cost, and correctness. The dynamic negotiation not only allows users to adapt their needs dynamically, but also lets providers utilize the network better. DSNP can be used in both wireline and wireless networks. It is, however, particularly useful in the mobile environment. To demonstrate the usefulness of DSNP, a reference wireless QoS architecture based on DiffServ is presented. Example applications and experimental results are illustrated.

Network science based approaches to design and analyze MANETs for military applications

Mobile ad hoc networks have become the basis of the militarys network-centric warfare (NCW) approach. However, for NCW to be successful, it is imperative that the networks be designed in a robust manner with the capability to produce consistent predictable results despite the uncertainties of the underlying environment. This underscores the need for formal systematic methodologies to design and predict performance of such networks. The challenges of mobile ad hoc networking combined with those associated with the stringent requirements posed by NCW systems, however, are daunting, and thus no systematic design techniques for NCW system design exist. To address this problem, a joint project was initiated between CERDEC and Telcordia Technologies to develop the Network Engineering Design Analytic Toolset (NEDAT) - a toolset that applies network-science-based approaches to design MANETs for use in NCW. Rooted in formal/analytic techniques, NEDAT can be used to design MANETs for use in NCW given information about available resources and performance objectives, analyze performance of a given NCW network, and understand design trades.

A novel approach to OSPF-area design for large wireless ad-hoc networks

To build ad-hoc networks with hundreds or even thousands of nodes, the network must be split into relatively independent layer 3 clusters. There are currently no general approaches or methodologies for the creation of domains that take into account the following important engineering constraints: balanced domains, minimal inter-domain traffic, robust network design. Moreover, there is also no contribution that specifically addresses the problem of area formation for OSPF-based ad hoc networks. By assuming that the creation of layer 3 clusters is done after layer 2 topology management has set local radio parameters, we have re-formulated the problem at hand in a graph theoretic framework and found a strong connection between the problem of area design and a classical problem in graph theory, the graph partitioning (GP) problem. The limitation of GP algorithms (GPAs) is that they are OSPF-agnostic and, therefore, are not capable of solving the problem of robust backbone network (Area 0) design. We here propose a two-step approach for OSPF area design: the first step consists of an efficient GPA that will create areas (including a rough Area 0 design), and the second step consists of ad-hoc heuristics that are able to ameliorate the Area 0 design as well as factoring in OSPF specific metrics.