The widespread availability of mobile wireless devices offers growing opportunities for the formation of temporary networks with only intermittent connectivity. These intermittently-connected networks (ICNs) typically lack stable end-to-end paths. In order to improve the delivery rates of the networks, new store-carry-and-forward protocols have been proposed which often use message replication as a forwarding mechanism. Message replication is effective at improving delivery, but given the limited resources of ICN nodes, such as buffer space, bandwidth and energy, as well as the highly dynamic nature of these networks, replication can easily overwhelm node resources. In this work we propose a novel node-based replication management algorithm which addresses buffer congestion by dynamically limiting the replication a node performs during each encounter. The insight for our algorithm comes from a stochastic model of message delivery in ICNs with constrained buffer space. We show through simulation that our algorithm is effective, nearly tripling delivery rates in some scenarios, and imposes little overhead.

A global-scale low cost outdoor Internet access infrastructure is finally attainable. Emerging projects are leveraging the proliferation of private Wi-Fi networks to build a global-scale ubiquitous access infrastructure from autonomous, independently owned Internet connections at homes and other private properties. To ensure the trace ability and accountability required by the broadband ISPs and private owners of these Wi-Fi networks, reliable authentication and authorization are needed. This paper describes authentication on the edge, a localized and distributed authentication method for open Wi-Fi networks. Three main ideas are used to adapt to the variability and unreliability of these networks: the use of certificate-based authentication, the distribution of a segmented certificate revocation list to all entities and the self organization of access points into a social lookup network. These methods achieve the scalability needed for the overwhelming size and volume of a global network and increase resiliency against temporary failures in the infrastructure.

Abstract — Fueled by the competing DSL and Cable technologies, residential broadband access has seen a significant spread in availability to the point that many users have a choice from several ISPs. At the same time, 802.11 networks have spread rapidly in the residential area, and it is common for neighbors to be able to access each other’s wireless routers. End-users can leverage this diversity to improve their Internet connectivity at no additional cost by pooling all available Internet connections, both their own and their neighbors ’ via wireless. In this paper we present our design and evaluation of flow scheduling algorithms in PERM, a framework for practical end-host multihoming. PERM scheduler employs automated on-line analysis of the endusers’ networking behaviors, and exploits the recognized patterns to achieve high-performance scheduling at flow level. We verify our models of end-user’s network traffic with large residential TCP traces. Based on these models we propose algorithms for scalable pre-probing and hybrid flow scheduling. Intensive experiments in our prototype testbed show that PERM scheduler reduces the latency by up to 50 % for light-volume flows, and reduces the mean transmission time of heavy-volume flows by nearly 28 % and 62 % compared with a single Cable or DSL connection respectively. The PERM scheduler also out-performs algorithms for enterprise multihoming by up to 15 % and 27% in mean transmission time for light- and heavy-volume flows respectively. I.