Gregory Lauer

Hierarchical Routing for Very Large Networks

This paper presents a hierarchical routing design undergoing implementation for the Survivable Packet Radio network project (SURAN) under the auspices of The Defense Advanced Research Project Agency. As in the previous Packet Radio network, this network is built on a carrier sense, multiple access broadcast channel and is populated with mobile store and forward nodes known as packet radio units, or PRs. The goals of SURAN are to create a large distributed network of 1,000 to 10,000 nodes with a redundant, fluid control structure that is capable of surviving the loss of components and other more active threats against the network control structure. Key to the success of this network are name servers which relate the current location of a device to a network address, access controllers which curtail network membership and privileges, network monitors which report on the control structure and network behavior and, finally, super*clusterheads which are responsible for the distributed routing control. The super*clusterheads create hierarchical addresses for each PR and compute the best routes between clusters at each level. This paper discusses issues associated with clustering: membership definition, route creation, distribution and change.

A secure content network in space

We present a content network architecture for a cluster of satellites flying in low Earth orbit. The cluster uses a dynamic wireless network to interconnect the satellites and has an intermittent link to the ground. Even though a cluster of satellites fly in formation, their relative positions can vary widely, and occasionally the cluster can disperse and regroup in order to avoid obstacles or to affect a better arrangement. The network, therefore, is a MANET with elements of a disruption tolerant network. Further, data security is a fundamental concern. Our approach is to layer a content network over the wireless network, supporting multiple qualities of service and multiple independent levels of security.

Performance analysis of rate-based congestion control algorithm for receiver-directed packet-radio networks

The performance of a congestion control algorithm developed for DARPAs Survivable Adaptive Networking (SURAN) packet radio network is discussed, focusing on throughput-delay characteristics, max-min fairness, speed of response, and algorithm robustness. It is shown, through analysis and simulation, that the algorithm effectively regulates source flows without severely limiting network throughput and achieves max-min fairness in a large class of situations. The algorithm can achieve max-min fair flow allocation in a large class of situations. A class of situations where fairness is not achieved, due to channel access interactions, is also discussed.<<ETX>>

Information dissemination in disadvantaged wireless communications using a data dissemination service and content data network

Disadvantaged wireless communications, such as those in fractionated spacecraft systems, need real-time, reliable, and fault tolerant information dissemination from information producers (such as sensors) to information consumers (such as information exploitation, analysis, or command and control systems). Such systems are well-suited to the publishsubscribe paradigm, but cannot afford the large footprint of many publish-subscribe systems and do not provide the underlying high-bandwidth, stable connectivity many publish-subscribe systems assume. Similarly, publish-subscribe systems cannot, by themselves, provide the real-time performance and quality of service needed by many missioncritical and spacecraft applications; they need enforcement and control provided by an underlying network. This paper presents a concept for a dissemination system suited to space-borne platforms that combines a lightweight implementation of the OMGs Data Dissemination Service with a simplified Content Delivery Network. The result is a topic-based publish-subscribe information dissemination service that supports decoupled publishers and subscribers of varying numbers, automated failover, and quality of service (QoS), coupled with a topic-based network that can enforce QoS parameters and efficiently deliver published messages based on the subscriptions registered by consumers.

A concept for publish-subscribe information dissemination and networking

Although IP and its overlying protocols, such as TCP and UDP, are ubiquitous, they were originally designed for point-to-point connections between computers in reasonably fixed locations. They are less suited to mobile networks and broadcast communications. In this paper, we present an alternative to IP that is based on a publish-subscribe approach. The approach that we present combines an application publish-subscribe programming model with a content delivery network, which provides several advantages in certain communication environments, including quality of service based on application level needs; efficient support for reliable broadcast; support for disadvantaged, intermittent, and limited communications; and more efficient reliability and fault tolerance. The paper presents our approach, based on a streamlined Data Distribution Service and simplified Content Delivery Network, a motivating example in which the publish-subscribe based distribution and network provides advantages, and a contrast to TCP/IP in the example context.

Distributed resource control using shadowed subgraphs

As software defined networks (SDN) grow in size and in number, the problem of coordinating the actions of multiple SDN controllers will grow in importance. In this paper, we propose a way of organizing SDN control based on coordinated subgraph shadowing. Graphs are a natural way to think about and describe SDN activity. Subgraphs provide a means to share a subset of a networks resources. Shadowing provides a means to dynamically update shared subgraphs. Leveraging advances in graph databases and our shadowing messaging technique, we discuss our implementation of a multi-domain virtual private network (VPN) using multi-protocol label switching (MPLS).