Enriched Classification and Dynamic Tunneling as Elementary Internet Mechanisms

We make the case that mechanisms for enriched classification and dynamic tunneling with a common elementary protocol is both necessary and sufficient for facilitating mobile IP services in highly environments. Moreover, we claim that device initiated handoffs simplify the network infrastructure and are in general more suitable in highly mobile and heterogeneous environments. We discuss our preliminary work to validate these claims based both on simulation models and experimental prototyping

A Simple Loss Differentiation Approach to Layered Multicast

Layered multicast is a promising technique for broadcasting adaptive-quality TV video to heterogeneous receivers. While several layered multicast approaches have been proposed, prior work has identified several problems including significant and persistent instability in video quality, arbitrary unfairness with other sessions, low access link utilization due to conservative bandwidth allocation, and problems with receiver synchronization. In this paper we propose a new layered multicast scheme, where we exploit a simple, coarse-grained, two-tier loss differentiation architecture to achieve stable and fair bandwidth allocation for viewers. Despite the simplicity of our loss differentiation model, we show that it achieves most of the benefits of complex and costly priority dropping schemes. In addition, our protocol is receiver-driven and thus retains the incentives to limit bandwidth usage that are not present in existing priority dropping schemes. Keywords--- multicast, layered video,..

On Static Reachability Analysis of IP Networks

The primary purpose of a network is to provide reachability between applications running on end hosts. In this paper, we describe how to compute the reachability a network provides from a snapshot of the configuration state from each of the routers. Our primary contribution is the precise definition of the potential reachability of a network and a substantial simplification of the problem through a unified modeling of packet filters and routing protocols. In the end, we reduce a complex, important practical problem to computing the transitive closure to set union and intersection operations on reachability set representations. We then extend our algorithm to model the influence of packet transformations (e.g., by NATs or ToS remapping) along the path. Our technique for static analysis of network reachability is valuable for verifying the intent of the network designer, troubleshooting reachability problems, and performing "what-if" analysis of failure scenarios