Residential broadband consumption is growing rapidly, increasing the gap between Internet service provider (ISP) costs and revenues. Meanwhile, proliferation of Internet-enabled devices is congesting access networks, degrading end-user experience, and affecting content provider monetization. In this paper, we propose a new model whereby the content provider explicitly signals fast- and slow-lane requirements to the ISP on a per-flow basis, using open APIs supported through software defined networking (SDN). Our first contribution is to develop an architecture that supports this model, presenting arguments on why this benefits consumers (better user experience), ISPs (two-sided revenue), and content providers (fine-grained control over peering arrangement). Our second contribution is to evaluate our proposal using a real trace of over 10 million flows to show that video flow quality degradation can be nearly eliminated by the use of dynamic fast-lanes, and web-page load times can be hugely improved by the use of slow-lanes for bulk transfers. Our third contribution is to develop a fully functional prototype of our system using open-source SDN components (Openflow switches and POX controller modules) and instrumented video/file-transfer servers to demonstrate the feasibility and performance benefits of our approach. Our proposal is a first step towards the long-term goal of realizing open and agile access network service quality management that is acceptable to users, ISPs, and content providers alike.

Access networks, largely based on DSL or cable links, continue to be the bandwidth bottleneck between device-rich households and high-speed core networks, causing frustration for both end-users and content service providers (CSPs). In this paper, we advocate that the scarce bandwidth resource on the access link be managed jointly, under software control, by the Internet service provider (ISP), consumer, and CSP. Our first contribution is to develop software defined networking (SDN) APIs for bandwidth control at fine-grain (per-flow) by the CSP and at coarse-grain (per-device) by the consumer, and highlight the benefits of such an architecture for all entities. Second, we develop an economic model to guide the ISP in determining bandwidth allocation that balances the needs of the CSP against those of the consumer, and demonstrate its utility via simulation of trace data comprising over 10 million flows. Finally, we prototype our system using commodity home routers and open-source SDN platforms, and conduct experiments in a campus-scale network to demonstrate how our scheme permits proactive and reactive improvement in end-user experience.

Enhancing quality-of-service (QoS) for specific traffic streams by assigning them to "fast-lanes" on the broadband Internet service is a subject of intense ongoing debate. While Internet Service Providers (ISPs) have clear economic imperatives for fast-lanes paid by content service providers (CSPs), proponents of net-neutrality argue that consumer interest will be ignored in the selection of traffic thus prioritized. In this paper we propose a new solution in which ISP fast-lanes have "two-sided" control, i.e. by both consumers and CSPs. Our contributions are two-fold: (1) We develop an architecture in which ISP-operated fast-lanes can be controlled at fine-grain (per-flow) by the CSP and at coarse-grain (per-device) by the consumer, and argue why we think such an architecture can meet the needs of all three parties; and (2) We develop an economic model to guide the ISP in determining fast-lane allocation that balances the needs of the CSP against those of the consumer, and evaluate our model via simulation of trace data comprising over 10 million flows.

Residential broadband gateways (comprising modem, router, and Wi-Fi access point), though individually consuming only 5-10 Watts of power, are significant contributors to overall network energy consumption due to large deployment numbers. Moreover, home gateways are typically always on, so as to provide continuous online presence to household devices for VoIP, smart metering, security surveillance, medical monitoring, etc. A natural solution for reducing the energy consumption of home gateways is to leverage the overlap of Wi-Fi networks common in urban environments and aggregate user traffic on to fewer gateways, thus putting the remaining to sleep. In this paper we propose, evaluate, and prototype an architecture that overcomes significant challenges in making this solution feasible at large-scale. We advocate a centralized approach, whereby a single authority co-ordinates the home gateways to maximize energy savings in a fair manner. Our solution can be implemented across heterogeneous ISPs, avoids client-side modifications (thus encompassing arbitrary user devices and operating systems), and permits explicit control of session migrations. We apply our solution to Wi-Fi traces collected in a building with 30 access points and 25,000 client connections, and evaluate via simulation the tradeoffs between energy savings, session disruptions, and fairness. We then prototype our system on commodity Wi-Fi access points, test it in a two-storey building emulating 6 residences, and demonstrate radio energy reduction of over 60 percent with little impact on user experience.

Link aggregation, or multi-band striping, has been used in wireless backhaul systems to overcome the limitations of bandwidth and transmission range. Work-conserving and in-sequence delivery are essential but conflicting requirements in multi-band striping systems. Previous schemes can achieve one or the other, but not both. The heterogeneous channel and time varying data rate in multi-band wireless backhaul systems present additional challenges. We aim at designing a multi-band striping algorithm to achieve both work-conserving and in-sequence delivery in the heterogeneous time-varying multi-band wireless backhaul system. We propose a parallel processing architecture for multi-band aggregation, and derive the necessary conditions for such system to achieve sequence preserving and work conserving. An optimum set of timing controls is developed and proved to provide the best performance. We design a work-conserving in-sequence striping algorithm and prove it to be sequence preserving and work conserving. The algorithm is then extended to practical data granularity. Performance analysis and simulation results demonstrate that our designs are able to preserve data sequence, reduce delay, and achieve 100% channel utilization.

Residential broadband consumption is growing rapidly, increasing the gap between ISP costs and revenues. Meanwhile, proliferation of Internet-enabled devices is congesting access networks, frustrating end-users and content providers. We propose that ISPs virtualize access infrastructure, using open APIs supported through SDN, to enable dynamic and controlled sharing amongst user streams. Content providers can programmatically provision capacity to user devices to ensure quality of experience, users can match the degree of virtualization to their usage pattern, and ISPs can realize per-stream revenues by slicing their network resources. Using video streaming and bulk transfers as examples, we develop an architecture that specifies the interfaces between the ISP, content provider, and user. We propose an algorithm for optimally allocating network resources, leveraging bulk transfer time elasticity and access path space diversity. Simulations using real traces show that virtualization can reduce video degradation by over 50%, for little extra bulk transfer delay. Lastly, we prototype our system and validate it in a test-bed with real video streaming and file transfers. Our proposal is a first step towards the long-term goal of realizing open and agile access network service quality management that is acceptable to users, ISPs and content providers alike.

Growing demand for streaming, voice and interactive gaming applications emphasize the importance of quality of service (QoS) provisioning in the Internet, particularly the need for maximum end-to-end delay guarantee. Current methods of QoS provisioning have either scalability concerns or cannot guarantee end-to-end delay with acceptable packet loss unless bandwidth is over-provisioned. While low jitter guarantee is required for streaming applications, maximum end-to-end delay is also required for VoIP and interactive games. We propose, analyze the stability and demonstrate the viability of three combined rate and end-to-end delay controls. The stability analysis is done on a fluid network model with greedy flows showing that all controls are globally asymptotically stable without information time lags and one of them is also globally asymptotically stable with arbitrary time lags; however it substantivally under-utilizes the network. Another control, which numerically demonstrates stability with arbitrary time lags, is implemented in edge and core routers of our WAN-in-Lab with long haul links. The prototype implementation confirms its viability and its advantage over the differentiated service architecture. The viability of the two other controls is shown by detailed NS2 packet-based simulations of an eight-node real core network.

reFLect is a new functional language, developed at Intel for use in hardware design and verification. It contains features intended to facilitate the construction, analysis, and manipulation of the language's own programs. It is also intended to be the executable subset of the term language of a theorem prover based on higher order logic.In this paper, we consider core reFLect---a language that extends a polymorphically typed λ-calculus with a datatype for programs and with constructs for splicing programs into programs and for defining functions that inspect and modify programs. We prove that the reduction semantics for this language is strongly normalizing and confluent. We also give a set-theoretical denotational semantics for the language and prove that the reduction semantics is sound with respect to the denotational semantics. These results provide the basis for developing the semantics of reFLect's extension of higher order logic and proving its soundness.

As processor performance continues to improve, more emphasis must be placed on the performance of the memory system. In this paper, a detailed characterization of data cache behavior for individual load instructions is given. We show that by selectively applying cache line allocation according the characteristics of individual load instructions, overall performance can be improved for both the data cache and the memory system. This approach can improve some aspects of memory performance by as much as 60 percent on existing executables.

No abstract available.