Ethernet is the indisputable de facto technology for local area networks due to its simplicity, low cost, and wide-scale adoption. In recent times, Ethernet has entered new networking areas, such as Metro Area Network (MAN) and Industrial Area Network (IAN), where specialized protocols dominate the market. In addition to the well known advantages, Ethernet acts as the common platform to integrate multiple protocols. However, Ethernet falls short of the stringent resilience requirements mandated by applications in MEN and IAN, despite progress made by the community on additional standardization. We describe a new approach for swift failure detection and recovery in Ethernet ring topologies called Rapid Ring Recovery (RRR). RRR is based on the novel usage of multiple virtual rings. Our implementation augmenting an off-the-shelf Ethernet switch shows that RRR reconverges after a fault in 294 microseconds while sustaining the loss of only eight large frames at 95 percent traffic load.

Efficient network provisioning mechanisms that support service differentiation are essential to the realization of the Differentiated Services (DiffServ) Internet. Building on our prior work on edge provisioning, we propose a set of efficient dynamic node and core provisioning algorithms for interior nodes and core networks, respectively. The node provisioning algorithm prevents transient violations of service level agreements (SLA) by predicting the onset of service level violations based on a multiclass virtual queue measurement technique, and by automatically adjusting the service weights of weighted fair queueing schedulers at core routers. Persistent service level violations are reported to the core provisioning algorithm, which dimensions traffic aggregates at the network ingress edge. The core provisioning algorithm is designed to address the difficult problem of provisioning DiffServ traffic aggregates (i.e., rate-control can only be exerted at the root of any traffic distribution tree) by taking into account fairness issues not only across different traffic aggregates but also within the same aggregate whose packets take different routes through a core IP network. We demonstrate through analysis and simulation that the proposed dynamic provisioning model is superior to static provisioning for DiffServ in providing quantitative delay bounds with differentiated loss across per-aggregate service classes under persistent congestion and device failure conditions when observed in core networks.

The successful operation of emerging public wireless local-area networks requires flexible network mechanisms that can support differentiated or tiered services for a variety of applications such as bursty transactional Web applications, as well as reservation demanding voice and video applications. Congestion pricing has been proposed as one promising solution to traffic control because it accurately models the cost that each user's traffic imposes on network congestion points. The underlying assumption of congestion pricing is that users will respond to a monetary-based price signal to maximize their own utility. We observe, however, that monetary service charge is largely a business concern and not a traffic control concern because operators and users prefer simple, predictable, and stable service charges such as flat-rate or block-rate charging. Therefore, we argue, that traffic control techniques such as congestion pricing should be decoupled from monetary service charges. Under such a new regime, however, a user's response to a nonmonetary price signal would be quite different from utility maximization, and without the appropriate incentives for users to cooperate such a regime would lead to the "tragedy of the commons" phenomenon, undermining any future differentiated service offerings by wireless Internet service providers. To address this problem, we propose wireless incentive engineering mechanisms for mobile devices (MDs) and access points (APs) that provide incentives for mobile users to cooperatively use different classes of services without relying on monetary service charging. Wireless incentive engineering possesses a number of beneficial properties including minimizing the algorithmic and protocol overhead on MDs and APs, Nash bargaining fairness, and incentive compatibility for mobile users promoting the truthful selection of service class and bandwidth declaration. We use analysis, simulation, and experimental results from a wireless testbed to demonstrate the effectiveness of wireless incentive engineering.

Traffic regulation in public and private wireless LANs face a number of significant challenges, particularly in commercial networks where there is a need for efficient regulation of bursty transactional applications, support for bandwidth reservation services while inhibiting bandwidth hogging by mobile devices, and providing incentives for user cooperation. We take a new approach to solving these problems by applying incentive engineering techniques to wireless access networks. We design two incentive-based allocation service classes: an instantaneous allocation (IA) class, which provides better throughput, and a stable allocation (SA) class, which provides better allocation stability. Our approach possesses a number of beneficial properties including minimizing the algorithmic and protocol overhead on mobile devices, Nash bargaining fairness for the IA service, and incentive compatibility for mobile users promoting the truthful selection of service class and bandwidth declaration. We use analysis, simulation and experimental results from a wireless testbed to demonstrate the effectiveness of wireless incentive engineering.

A key consideration in building differentiated network services is the feasibility of maintaining stable and consistent service level agreements across multiple networks where allocations are made only on the edges. To investigate this, we consider a game theoretic model of capacity provisioning in a differentiated services Internet. The players are one raw-capacity seller per network, one broker per service per network, and users, to play the roles of wholesellers, retailers and end users respectively in a two-tier wholeseller/retailer market. Based on this model, we are able to construct an explicit necessary and sufficient condition for the stability of the game, which determines the sustainability of a given set of SLA configurations among peering ISP. The analytical results are validated with simulations of user and broker dynamics, using distributed progressive second price auctions as the spot market mechanism in a scenario with three interconnected networks, and two services.

This paper presents a decentralized auction-based approach to pricing of edge-allocated bandwidth in a differentiated services Internet. The players in our network economy model are one raw-capacity seller per network, one broker per service per network, and users, to play the roles of whole-sellers, retailers, and end-buyers, respectively, in a two-tier wholeseller/retailer market, which is best interpreted as a "sender-pay" model. With the progressive second price auction mechanism as the basic building block, we conduct a game theoretic analysis, deriving optimal strategies for buyers and brokers, and show the existence of networkwide market equilibria. In addition to pricing, another key consideration in building differentiated network services is the feasibility of maintaining stable and consistent service level agreements across multiple networks where demand-driven dynamic allocations are made only at the edges. Based on the proposed game-theoretic model, we are able to construct an explicit necessary and sufficient condition for the stability of the game, which determines the sustainability of any set of service level agreement configurations between Internet service providers. These analytical results are validated with simulations of user and broker dynamics, using the distributed progressive second price auction as the spot market mechanism in a scenario with three interconnected networks, and two services based on the proposed standard expedited forwarding and assured forwarding per-hop behavior.

Existing mobile systems (e.g., mobile IP, mobile ATM and third generation cellular systems) lack the intrinsic architectural flexibility to deal with the complexity of supporting adaptive mobile applications in wireless and mobile environments. We believe that there is a need to develop alternative network architectures from the existing ones to deal with the demands placed on underlying mobile signalling, adaptation management and wireless transport systems in support of new mobile services, e.g. interactive multimedia and web access. In this paper we present the design, implementation and evaluation of mobiware, a middleware technology that enables the introduction of new services in mobile networks. Mobiware provides a toolkit that service providers can utilize to build services that can dynamically exploit the intrinsic scalable properties of mobile multimedia applications in response to time-varying mobile network conditions. Based on an open programmable networking paradigm, mobiware runs on mobile devices, wireless access points and mobile-capable switch/routers providing a set of open programmable interfaces and distributed objects for adaptive mobile networking. Mobiware is software-intensive and is built on CORBA and Java distributed object technologies. The source code for mobiware v1.0 is freely available (comet.columbia.edu/mobiware) for experimentation.

In th ~ paper we introduce uniuergal mobile channel, a new mobde communications abstraction that enables users and service providers to program apphcation-specific adaptive mobde services into a ce~ular Internet. Universal mobde channels are capable of supporting distinct adaptive qurdity of service control and mobfity management services over the same ce~ular access network infrastructure. Buflt on a split-leuel adaptation control scheme that operates at the ap pfication and network Ieveh, universal mobde channek offer a set of we ~ defined open programmable interfaces to actively exploit the intrinsic scdabfity of adaptive mobfle ap phcations in ce~dar 1P networks. Universal mobde channeb can be programmed and expose interfaces that include: G) utility curves, which capture the adaptive nature of mobde applications in terms of the range of bandwidth over which they can successftiy operate; (ii) adaptation policy, which enables adaptive mobde apphcations to program per-session adaptation time-scales and bandwidth gramdarities rerdizing novel apphcation-specific adaptive servic ~ and (iii) session policy, which enables users to specify the relative importance of flows/sessions within the same universfl mobde channel. To maintain adaptive services, universal mobde channek periodically probe the ce~tiar access network using a distributed network dgonthm achieving utility-based max-min jairness. 1