Suman Srinivasan

Airborne traffic surveillance systems: video surveillance of highway traffic

Timely information about highway traffic conditions is very important for the Department of Transportation (DOT) and other relevant agencies. Such live information would be very important when traffic incidents or accidents occur. An aerial view is the best for traffic situations, particularly over highways. Unmanned aircraft equipped with video cameras and/or other sensors may be able to deliver the necessary information through video images with relatively low operational costs and risks to human life. ATSS (Airborne Traffic Surveillance System), a project funded by the Florida Department of Transportation, attempts to make this vision a reality. This paper describes how the University of Florida research team implemented a system for ATSS from the ground up, using unmanned aerial vehicles, digital video encoding, and transmission of data and multimedia video streams over FDOTs microwave IP networks.

NetServ Framework Design and Implementation 1.0

Eyeball ISPs today are under-utilizing an important asset: edge routers. We present NetServ, a programmable node architecture aimed at turning edge routers into distributed service hosting platforms. This allows ISPs to allocate router resources to content publishers and application service providers motivated to deploy content and services at the network edge. This model provides important benefits over currently available solutions like CDN. Content and services can be brought closer to end users by dynamically installing and removing custom modules as needed throughout the network. Unlike previous programmable router proposals which focused on customizing features of a router, NetServ focuses on deploying content and services. All our design decisions reflect this change in focus. We set three main design goals: a wide-area deployment, a multi-user execution environment, and a clear economic benefit. We built a prototype using Linux, NSIS signaling, and the Java OSGi framework. We also implemented four prototype applications: ActiveCDN provides publisher-specific content distribution and processing; KeepAlive Responder and Media Relay reduce the infrastructure needs of telephony providers; and Overload Control makes it possible to deploy more flexible algorithms to handle excessive traffic.

7DS - A Modular Platform to Develop Mobile Disruption-Tolerant Applications

Due to the low density of mobile devices or their limits in wireless radio range, a continuous network connectivity cannot be sustained in mobile disruption-tolerant networks. In these networks traditional networking models relying on end-to-end communication cease to work. These type of mobile disconnected networks can only support opportunistic, store-carry-forward communication. Furthermore, due to mobile nodes that dynamically join and leave the network the concept of a single, always-on server is unreasonable. In these scenarios, mobile users have to rely on node and service discovery and applications that cope with network disruptions. 7DS introduces a new platform to develop mobile applications for disruption-tolerant mobile networks. 7DS provides the necessary transport and application layer functionalities for mobile nodes to exchange information in store-carry-forward communication. 7DS has been developed as a modular platform that provides application developers with core underlying functionalities required for mobile disruption-tolerant communication. We discuss the primary requirements of mobile applications and introduce two new applications implemented on top of the 7DS platform. These applications assist mobile users in data and event sharing in a server-less and disconnected networking environment.

7DS - Node Cooperation and Information Exchange in Mostly Disconnected Networks

When the node density in a network decreases below the level necessary to sustain ad-hoc and mesh networks, communication can succeed only by leveraging node mobility and transitioning to message-based communications. In the 7DS (Seven Degrees of Separation) project, we have been investigating how to emulate two core Internet services, namely Web access for information retrieval and email for delivering messages from mobile nodes to the Internet. We have implemented and evaluated a 7DS prototype system that leverages search, feedback and propagation limits to build a scalable system that can deliver data to and from mobile nodes. 7DS makes data exchange in disconnected networks possible by providing an application-level set of protocol services that will enable exchange of information between peer devices. It enables dynamic information exchange by using a proxy server, a multicast query system, a search engine, and a transport entity. With these entities, 7DS can perform efficient and transparent data exchange among peers in the absence of a network connection. Data exchange with the larger Internet occurs when peers enter or exit the peer network.

NetServ: dynamically deploying in-network services

We present NetServ, an extensible architecture for core network services for the next generation Internet. The functions and resources available on a network node are broken up into small and reusable building blocks. A new core network service is implemented by combining the building blocks, and hosted in a sandbox-like execution environment that provides security, portability, resource control, and the ability to deploy modules dynamically. We describe our first prototype, a novel combination of the Click router and the Java-based OSGi module system. Our measurement results indicate that the processing overhead incurred by the Java layer is a reasonable trade-off for the level of modularity we achieve in our system.

Accelerating Service Discovery in Ad-Hoc Zero Configuration Networking

Zero Configuration Networking (Zeroconf) assigns IP addresses and host names, and discovers service without a central server. Zeroconf can be used in wireless mobile ad-hoc networks which are based on IEEE 802.11 and IP. However, Zeroconf has problems in mobile ad-hoc networks as it cannot detect changes in the network topology. In highly mobile networks, Zeroconf causes network overhead while discovering new services. In this paper, we propose an algorithm to accelerate service discovery for mobile ad-hoc networks. Our algorithm involves the monitoring of network interface changes that occur when a device with IEEE 802.11 enabled joins a new network area. This algorithm allows users to discover network topology changes and new services in real-time while minimizing network overhead.

ActiveCDN: Cloud Computing Meets Content Delivery Networks

Content delivery networks play a crucial role in today’s Internet. They serve a large portion of the multimedia on the Internet and solve problems of scalability and indirectly network congestion (at a price). However, most content delivery networks rely on a statically deployed configuration of nodes and network topology that makes it hard to grow and scale dynamically. We present ActiveCDN, a novel CDN architecture that allows a content publisher to dynamically scale their content delivery services using network virtualization and cloud computing techniques.

CCNxServ: Dynamic service scalability in information-centric networks

Content-centric networks promise to address content networking issues in a better way than todays host-based networking architecture. But content-centric networking does not inherently address the issue of services, particularly service scalability and mobility. We present our work on CCNxServ, a system that allows for dynamic service deployment and scalability in a content-centric networking implementation (CCNx) through an intuitive use of the content naming scheme. It thus extends the concept of content-centric networking towards services.

Measurements of Multicast Service Discovery in a Campus Wireless Network

Applications using multicast service discovery protocols, such as iTunes, have become increasingly popular. However, multicast service discovery protocols generate significant network traffic overhead, especially in a wireless network. We measure and analyze the traffic of one of the most widely deployed multicast service discovery protocols, DNS-SD/mDNS, in a campus wireless network where a single multicast domain serves a large number of users. We define three service discovery models which correspond to different service discovery behaviors. We compare these three models in terms of packet overhead and service discovery delay for different network sizes and service lifetime assumptions. The measurement shows that mDNS traffic consumes about 13 percent of the total bandwidth of the network.

BBS-ONE: Bulletin board and forum system for mobile opportunistic networks

Electronic bulletin boards and forum systems are commonly used to exchange opinions, news, event notifications, documents and other media on the Internet. However, such systems usually require a central server hosting the content. Such servers cannot be installed in ad-hoc opportunistic wireless networks, which are created when mobile devices congregate to form a localized and short-lived network without Internet connectivity. We present BBS-ONE, a bulletin board system for opportunistic networks, and describe its service model and implementation. BBS-ONE works in highly mobile opportunistic networks, considers the mobility of nodes, and allows nodes to operate even when churn is high when nodes join and leave the network. It transparently disseminates public data and posts and persists desired data by operating in a peer-to-peer fashion and using a store-carry-forward model of communication. It maintains the data consistency needed for a BBS and forum system. We have implemented the application on generic desktop OS platforms (Windows, Linux, Mac) as well as a mobile platform (iPhone/iPod).