Oliver Yu

Reliable Blast UDP : predictable high performance bulk data transfer

High speed bulk data transfer is an important part of many data-intensive scientific applications. This paper describes an aggressive bulk data transfer scheme, called Reliable Blast UDP (RBUDP), intended for extremely high bandwidth, dedicated- or Quality-of-Service-enabled networks, such as optically switched networks. This paper also provides an analytical model to predict RBUDPs performance and compares the results of our model against our implementation of RBUDP. Our results show that RBUDP performs extremely efficiently over high speed dedicated networks and our model is able to provide good estimates of its performance.

Quanta: a toolkit for high performance data delivery over photonic networks

Quanta is a cross-platform adaptive networking toolkit for supporting the data delivery requirements of interactive and bandwidth intensive applications, such as Amplified Collaboration Environments. One of the unique goals of Quanta is to provide applications with the ability to provision optical pathways (commonly referred to as Lambdas) in dedicated photonic networks. This paper will introduce Quantas architecture and capabilities, with particular attention given to its aggressive and predictable high performance data transport scheme called Reliable Blast UDP (RBUDP). We provide an analytical model to predict RBUDPs performance and compare the results of our model against experimental results performed over a high speed wide-area network.

Adaptive networking for tele-immersion

Tele-Immersive applications possess an unusually broad range of networking requirements. As high-speed and Quality of Service-enabled networks emerge, it will becoming more difficult for developers of Tele-Immersion applications, and networked applications in general, to take advantage of these enhanced services. This paper proposes an adaptive networking framework to ultimately allow applications to optimize their network utilization in pace with advances in networking services. In working toward this goal, this paper will present a number of networking techniques for improving performance in tele-immersive applications and examines whether the Differentiated Services mechanism for network Quality of Service is suitable for Tele-Immersion.

Fairly adjusted multimode dynamic guard bandwidth admission control over CDMA systems

Guard-based call admission control schemes support admission priorities based on resources sharing with differentiated resource capacity limits. To minimize deviation from call blocking/dropping targets due to nonstationary call arrival condition, dynamic guard-based schemes with predictive adaptation control adjust differentiated capacity limits according to predicted future arrival rates based on specified estimation algorithms. Existing dynamic guard admission schemes are developed under the assumption of perfect estimation, which may not be possible in a highly nonstationary environment and, thus resulting in failures to maintain targeted blocking/dropping probabilities. This paper presents the fairly adjusted multimode-dynamic guard bandwidth scheme, which is a dynamic-guard-based scheme over code-division multiple-access systems with predictive adaptation control to adapt interference-based guard loading-limits under nonstationary call arrival condition; and reactive adaptation control to counteract arrival rate estimation errors. When the predictive adaptation control policy mode is not able to maintain long-term call blocking or dropping targets due to estimation error, this will trigger reactive adaptation control policy modes that include temporary blocking (preemption) of one or more lower priority classes subject to fairness constraints to ensure lower priority classes are not preempted at all costs during estimation error recovery. Analytical and simulation results show that proposed scheme is able to provide performance guarantees in terms of dropping probabilities under nonstationary traffic arrival and imperfect arrival rate estimation.

Intercarrier interdomain control plane for global optical networks

This paper presents the Photonic Interdomain Negotiator (PIN) as the secure global optical control plane architecture to interoperate multiple wavelength-routed network domains with incompatible local control planes. The PIN interdomain routing and wavelength assignment is characterized by constraint-based optical path-vector routing to determine end-to- end lightpath across multiple domains, and by conversion-aware wavelength discovery to resolve wavelength blocking during discovery phase. The PIN interdomain optical signaling is supported by the Robust Fast Optical Reservation Protocol (RFORP) to minimize reservation delay by employing parallel reservation processing in multiple domains along a domain-path, and to minimize wavelength blocking during reservation phase by employing localized rerouting.

End-to-end adaptive QoS provisioning over GPRS wireless mobile network

The General Packet Radio Service (GPRS) offers performance guaranteed packet data services to mobile users over wireless frequency-division duplex links with time division multiple access, and core packet data networks. This paper presents a dynamic adaptive guaranteed Quality-of-Service (QoS) provisioning scheme over GPRS wireless mobile links by proposing a guaranteed QoS media access control (GQ-MAC) protocol and an accompanying adaptive prioritized-handoff call admission control (AP-CAC) protocol to maintain GPRS QoS guarantees under the effect of mobile handoffs. The GQ-MAC protocol supports bounded channel access delay for delay-sensitive traffic, bounded packet loss probability for loss-sensitive traffic, and dynamic adaptive resource allocation for bursty traffic with peak bandwidth allocation adapted to the current queue length. The AP-CAC protocol provides dynamic adaptive prioritized admission by differentiating handoff requests with higher admission priorities over new calls via a dynamic multiple guard channels scheme, which dynamically adapts the capacity reserved for dealing with handoff requests based on the current traffic conditions in the neighboring radio cells. Integrated services (IntServ) QoS provisioning over the IP/ATM-based GPRS core network is realized over a multi-protocol label switching (MPLS) architecture, and mobility is supported over the core network via a novel mobile label-switching tree (MLST) architecture. End-to-end QoS provisioning over the GPRS wireless mobile network is realized by mapping between the IntServ and GPRS QoS requirements, and by extending the AP-CAC protocol from the wireless medium to the core network to provide a unified end-to-end admission control with dynamic adaptive admission priorities.

Multi-domain lambda grid data portal for collaborative grid applications

This paper presents the iGrid2005 demonstration of the multi-domain Lambda Grid data portal to enable collaborative Grid applications to retrieve gigabyte-size scientific datasets on demand over a wide-area Lambda Grid test-bed spanning across the United States and Europe. The data portal allows collaborative users to register and discover distributed datasets across a multi-domain Lambda Grid through a web-service based dataset registry and search engine, and to deliver the discovered datasets through dynamic established lightpaths to specified computing cluster locations for dataset manipulation. The data portal employs the novel Secure Photonic Inter-domain Negotiator (SPIN) as a secure multidomain control plane to set up dynamic lightpaths between the source and destination clusters for respective storage and manipulation of the discovered datasets over a multi-domain Lambda Grid. The data portal employs lamhda-aware middleware and transport protocol to optimize transfer of the discovered datasets over the dynamic established lightpaths. Implementation details and observed performance results from the demonstrations of the SPIN-based Lambda Grid data portal are reported.

Dynamic adaptive QoS provisioning over GPRS wireless mobile links

The General Packet Radio Service (GPRS) offers performance guaranteed packet data services to mobile users. A dynamic adaptive guaranteed quality-of-service (QoS) provisioning scheme is proposed over GPRS wireless mobile links via the guaranteed QoS media access control (GQ-MAC) protocol and the accompanying adaptive prioritized-handoff call admission control (AP-CAC) protocol to maintain QoS guarantees under the effect of mobile handoffs. The GQ-MAC protocol supports bounded access delay and packet-loss probability for respective delay and loss sensitive traffic, and dynamic adaptive resource allocation for bursty traffic. The AP-CAC protocol provides dynamic adaptive prioritized admission by differentiating handoff requests of different traffic classes with higher admission priorities over new calls via the dynamic multiple guard channels scheme, which adapts the channel capacity limits reserved for the multiple handoff request classes in each radio cell based on the current estimates of their arrival rates derived from the current number of ongoing calls in neighboring radio cells and the mobility pattern.

Integrated QoS support in 3G UMTS networks

The paper discusses the quality of service (QoS) requirements for each traffic class in a wireless environment and problems in implementing the QoS requirements in the CDMA based Universal Mobile Telecommunication Service (UMTS) network. In UMTS networks, the medium access control (MAC)/link access control (LAC) sublayer of the OSI layer 2 will be used for priority handling, QoS monitoring, and radio resource management for traffic flows from several users. The paper presents some suggestions to realize QoS requirements in the MAC/LAC sublayer along with restrictions imposed by the W-CDMA air interface.

Dynamic Control of Open Spectrum Management

This paper focuses on sharing of open spectrum under a new sharing policy of prioritized dynamic spectrum leasing, where the designated spectrum broker dynamically allocates time-varying unused licensed spectrum resources to secondary networks of various access priorities. The proposed optimal stochastically controlled dynamic guard bandwidth (OSC-DGB) scheme enables the spectrum broker to adapt differentiated capacity limits of open spectrum for prioritized connection accesses by secondary networks in anticipation of their access request rates, which are expected to be opportunistic and non-stationary. The differences in capacity limits determine the amount of guard band reserved for the higher priority secondary networks. This spectrum adaptation problem is formulated as a finite-horizon Markov decision process to minimize service denials of secondary networks according to their spectrum access priorities, which is solved through dynamic programming. Numerical results show that OSC-DGB enables close tracking of connection blocking targets while optimizing resource utilizations.