Kirthika Parmeswaran

Network QoS assurance in a multi-layer adaptive resource management scheme for mission-critical applications using the CORBA middleware framework

We present adaptive network QoS (quality of service) technology that provides ongoing, end-to-end assurance that critical traffic belonging to admitted flows has bounded queuing loss, delay, and jitter. Our technology uses a bandwidth broker to provide admission control, and leverages differentiated services and class of service functionality of high-end routers and switches for enforcement. The technology employs an integrated QoS treatment across a hybrid layer-2/layer-3 network and adapts to changes in mission requirements, work load and configurations; it uses discovery algorithms in these layers to maintain a current view of resource availability. Under the DARPA ARMS (adaptive and reflective middleware systems) program, our technology is being developed, integrated and validated in a CORBA-based multilayer resource management framework.

PECAN: policy-enabled configuration across networks

The Internet is growing to the point of needing more serious, scalable management infrastructure. Telecommunications companies and Internet service providers alike face the pressures of upgrading and provisioning their networks while constraining their infrastructure costs to maintain profitability and to stay competitive in an industry that is financially stressed with tight profit margins. In order to be financially successful in this environment, service providers will have to support a variety of services and applications on a combined packet infrastructure, carrying increased varieties of traffic with different performance characteristics and predictable levels of managed quality of service (QoS). Multi-protocol label switching (MPLS) traffic engineering enables service providers to engineer their networks to provide such QoS; however, this task brings along with it a plethora of management challenges. We discuss these management challenges and our experience with the design and implementation of a policy-based management system, PECAN, for managing MPLS networks. PECAN provides the ability for a network operator to define high-level policies that control the operation of the management system. These high-level policies control admission of traffic into the network based on the QoS guarantees required; placement of traffic flows on MPLS traffic engineered paths; and the feedback loop between network fault/performance monitoring and reconfiguration of the network to alleviate the effects of any observed problems.

Building autonomic systems via configuration

Large classes of autonomic (self-managing, self-healing) systems can be created by logically integrating simpler autonomic systems. The configuration method is widely used for such integration. However, there are few formalized tools in support of this method for specification, compilation, diagnosis, reasoning, and distributed provisioning. As a result, the practice of this method is very costly and can lead to security failures. This paper presents a technique called Service Grammar for building these tools based on a novel analysis of protocols and distributed algorithms in a domain of interest. The technique is illustrated in the context of a realistic adaptive virtual private network. We show how lower-layer adaptive protocols can be composed to create adaptive behavior at a higher layer.

Adaptive network QoS in layer-3/layer-2 networks as a middleware service for mission-critical applications

We present adaptive network Quality of Service (QoS) technology that provides delay bounds and capacity guarantees for traffic belonging to mission-critical tasks. Our technology uses a Bandwidth Broker to provide admission control and leverages the differentiated aggregated traffic treatment provided by todays high-end COTS layer-3/2 switches. The technology adapts to changes in network resources, work load and mission requirements, using two components that are a particular focus of this paper: Fault Monitor and Performance Monitor. Our technology is being developed and applied in a CORBA-based multi-layer resource management framework.

The Mobile Application Server (MAS): An Infrastructure Platform for Mobile Wireless Services

There has been a surge of interest in developing advanced mobile voice and data services. One of the biggest challenges faced by service providers is to create new services efficiently and rapidly. We describe the motivation, architecture and design of the Mobile Application Server (MAS), a Java middleware prototype platform for mobile services which provides basic common building blocks required by mobile wireless applications, such as user profile management, location handling, device detection, content adaptation and e-wallet functions. The MAS is modular, flexible, and provides an open API for 3rd party service creation. Users can thus utilize a variety of access technologies (CDPD, cellular, 802.11, SMS, etc.) and delivery mechanisms (HTML, WML, VoiceXML, etc.) while application developers are spared the details of this heterogeneity. The MAS also interfaces to traditional telecommunications system (A/IN) elements such as SCPs as well as Next Generation Network (NGN) or converged-network elements such as Call Agents. We present application examples of the use of MAS, initial performance measurements and discuss some lessons learned from this experimental system. We conclude with directions for further work.

Intelligent application persistence in tactical wireless networks

Mobile tactical MANETs are subject to periods of intermittent connectivity and transient events of significant packet loss. Because of such disruptions, protocols and technologies have been proposed that are disruption and delay tolerant. One class of such systems works by storing messages/packets in the network. If connectivity to neighbors is lost, missing messages may be delivered when connectivity to neighbors is restored. This delay tolerant networking (DTN) technology aims to reliably deliver all the data that a source directs towards a receiver node. We suggest that in some cases it is of little utility and may even be counter-productive to persist and deliver all packets lost during a disruption episode. For example, in situational awareness applications, retransmitting many seconds or minutes of lost GPS tracks is not appropriate. Instead a snapshot of the current position of all tracked entities is preferable. Similarly in a multimedia stream or VOIP call, just the key missing information should be replayed. Not only does full retransmission of all missing packets introduce delays during retransmission, but also the bandwidth consumed during retransmission is wasted. Note that each application may have different semantics. Therefore determining what data is appropriate to deliver for a given application in order to recover from a temporary disconnection requires knowledge of the application semantics. In previous work, we proposed Heterogeneous Intelligent Filtering (HIF), a technology that intelligently filters and transforms data to match network capacity and end-user capability. In HIF, extraneous information not needed by the end-user is filtered by HIF agents. In this work2, we show how the HIF concept can be extended to the data and information persisted during disruptions. The information stored for later retransmission to previously disconnected receivers may consist of application state snapshots, summaries or transcripts of the missing data, or just those portions of a media stream judged to be relevant to the user at a given point in time. We describe our work on application aware persistence for real-time multimedia and tactical situational awareness applications. The middleware infrastructure of the HIF systems reported on in previous work is extended to support application aware persistence. We analyze the performance benefit of application persistence on a tactical situational awareness scenario. Application persistence is particularly useful when the end-device may be limited in its processing power and ability to render data, since it reduces the demands on the client application. Accordingly, we also illustrate the usefulness of our application aware persistence middleware in supporting multimedia and situational awareness applications implemented on handheld Android devices.

Intelligent content transformation in tactical wireless networks

Mobile tactical MANETs are interconnected via a quasi-static backbone network (QSN) that is relatively stationary and has substantial radio bandwidth capability. Because of high mobility and terrain sensitivity, the bandwidth available to mobile nodes within the MANET may vary significantly over time. During the periods where the bandwidth available is reduced, MANET nodes may be unable to handle the information load sourced from or distributed via the QSN. Furthermore, end-user devices and end-users themselves may have limited capability to receive/process data. Thus, the data delivered to tactical MANETs needs to be carefully managed. In previous work, we proposed Heterogeneous Intelligent Filtering (HIF) in multi-domain heterogeneous networks, for intelligent active filtering and transformation of the data to match network and end-user capacity. In this work2, we report on extending HIF to militarily important applications such as XMPP-based chat, SOA Web-services, and VOIP applications. We also provide experimental results based on outdoor testing of the filtering and content adaptation capabilities of HIF agents deployed in an HMS radio inter-network at Ft. Monmouth, NJ.

A Distributed Hierarchical Policy Management System for Security Control over Tactical Mobile Ad Hoc Networks

Tactical mobile ad hoc wireless networks can provide flexibility, agility, and mobility for dynamic network-centric warfare. They are designed to function without fixed infrastructure support. But, this design makes network security attacks hard to detect and control. For instance, an attacker could compromise one portion of the network by inducing a worm and then move to another portion of the network and replay the attack without being detected. In this paper, we describe a policy management system (PMS) that provides ubiquitous and consistent security policy control despite adverse conditions such as node mobility, node failures, network partitions, a compromise of the routing infrastructure, a high packet loss rate, and ongoing cyber attacks. We give performance results in a 47-node emulated network. Key challenges in tactical networks include a lossy environment with bit error rates as high as 0.001 and bandwidth as low as 500Kbits/s. TCP backs off in the face of packet loss and hence behaves poorly in such networks. Tactical network are also subject to cyber attacks that have the potential even to compromise the routing infrastructure. Our PMS architecture mitigates these issues by using a transport protocol that has two components, one oriented toward normal operation when the routing infrastructure is functioning and one oriented toward limited, but robust, operation even when the routing infrastructure has been compromised. In normal operation we use a reliable UDP protocol (RUDP) and in times of compromise we use a flooding protocol.

Fast Recovery and QoS Assurance in the Presence of Network Faults for Mission-Critical Applications in Hostile Environments

In a hostile military environment, systems must be able to detect and react to catastrophes in a timely manner in order to provide assurance that critical tasks will continue to meet their timeliness requirements. Our research focuses on achieving network quality of service (QoS) assurance using a Bandwidth Broker in the presence of network faults in layer-3 networks. Passive discovery techniques using the link-state information from routers provide for rapid path discovery which, in turn, leads to fast failure impact analysis and QoS restoration. In addition to network fault tolerance, the Bandwidth Broker must be fault tolerant and must be able to recover quickly. This is accomplished using a modified commercially available and open-source in- memory database cluster technology.

A toolkit for building secure, fault-tolerant virtual private networks

Dynamic coalition networks connect multiple administrative domains. The domains have a need to communicate, but have limited mutual trust. To establish communication services, these networks must be configured consistently with respect to global service requirements and security policies. The configuration must also be done in a way that respects the autonomy of the separate domains. Commercial network configuration tools do not provide sufficient functionality for this purpose. This document outlines a toolkit for solving these problems and reports on its deployment over a wide area network between Telcordia Technologies and BBNs TIC.