Architecture, design, and modeling of the OPSnet asynchronous optical packet switching node

An all-optical packet-switched network supporting multiple services represents a long-term goal for network operators and service providers alike. The EPSRC-funded OPSnet project partnership addresses this issue from device through to network architecture perspectives with the key objective of the design, development, and demonstration of a fully operational asynchronous optical packet switch (OPS) suitable for 100 Gb/s dense-wavelength-division multiplexing (DWDM) operation. The OPS is built around a novel buffer and control architecture that has been shown to be highly flexible and to offer the promise of fair and consistent packet delivery at high load conditions with full support for quality of service (QoS) based on differentiated services over generalized multiprotocol label switching

Quality of Service over Specific Link Layers: state of the art report

The Integrated Services concept is proposed as an enhancement to the current Internet architecture, to provide a better Quality of Service (QoS) than that provided by the traditional Best-Effort service. The features of the Integrated Services are explained in this report. To support Integrated Services, certain requirements are posed on the underlying link layer. These requirements are studied by the Integrated Services over Specific Link Layers (ISSLL) IETF working group. The status of this ongoing research is reported in this document. To be more specific, the solutions to provide Integrated Services over ATM, IEEE 802 LAN technologies and low-bitrate links are evaluated in detail. The ISSLL working group has not yet studied the requirements, that are posed on the underlying link layer, when this link layer is wireless. Therefore, this state of the art report is extended with an identification of the requirements that are posed on the underlying wireless link, to provide differentiated Quality of Service

The Squatting and Kicking strategies for self-provisioned, bandwidth resource sharing in multiclass networks

English: This article proposes a self-provisioned, Squatting and Kicking bandwidth resource sharing strategy for multiclass networks where differentiated services are not natively built. Moreover, this article provides a summary of the bandwidth constraints models and shows how the squatting and kicking strategies can be adapted to be the basis for a new bandwidth constraint model, which widens the range of techniques available to operators for bandwidth resource management in multiclass networks.Castellano: Este artículo propone unas estrategias para compartir ancho de banda en redes multi-clase de manera auto-gestionada, donde los servicios diferenciados no se soportan de manera nativa. Además, se provee una comparación de los modelos de ancho de banda limitado y cómo las estrategias "squat" y "kick" se pueden constituir como nuevo modelo. Dicho model ampliará el número de técnicas que los operadores tienen disponibles para la gestión de tráfico en redes multi-clase.Català: Aquest article proposa unes estratègies per a compartir l'amplada de banda en xarxes multi-classe de manera auto-gestionada, a on els serveis diferenciats no se suporten de manera nadiua. A més a més, se proveeix una comparació dels models d'amplada de banda limitat i com les estratègies "squat" i "kick" es poden constituir com a nou model. Aquest nou model ampliarà el nombre de tècniques de que disposen els operadors de xarxes multi-classe per a la gestió del tràfic

E3MS: A traffic engineering prototype for autoprovisioning services in IP/DiffServ/MPLS networks

This paper presents the testbed definition, implementation and trials of a new strategy for traffic autoprovisioning for MPLS and IP/DiffServ. This is the proof of concept of a new scenario for traffic engineering, for selfconfiguring control and end-to-end quality of service management by means of a tool based on Web Services. The system is structured in 3 layers: A Graphical User Interface, a Network Elements layer (an interface to physical devices) and, in the middle, a Network Management System layer, where decisions about admission, load balancing, path selection, rerouting and bandwidth allocation per class are taken. The system includes Dynamic Resource Allocation (DRA) and Background Monitoring System (BMS) modules to globally manage network resources. The so-called Squatter and Legalization mechanisms are introduced as novelties added to traffic engineering. Those strategies permit the use of part of the available resources from other classes only while unused by the class owning them. The trials hav validated the management system, using Cisco routers.Postprint (published version

Enhancement of QoS in voice-enabled networks using combination of MPLS and DiffServ

At its beginnings, the Internet Protocol was not meant for real-time applications such as voice and video. These conventional IP networks were limited to providing only best-effort QoS model which implies no QoS. Now voice traffic has been transmitted to IP-based networks instead of the conventional Public Switched Telephone Network (PSTN). Therefore, early adopters of this technology have noticed that for voice traffic to function as well as on conventional IP-based network as in PSTN, the transport techniques used by the IP-based network needed some additional policies and technique in place to accommodate the requirements of real-time data traffic. DiffServ is another QoS model used in IP networks, which differentiates IP traffic into classes each with certain priority. Implementing DiffServ, alone, can meet the SLA requirement in term of providing different QoS techniques based on the traffic type, but cannot ensure bandwidth, perapplication basis, so congested path may cause jitter, end to end delay or packet loss. MPLS was developed to combine the advantages of the connectionless layer 3 routing and the connection-oriented layer 2 forwarding, and provides per-hop data forwarding where it uses the label swapping rather than the layer 3 complex lookups in a routing table. Implementing MPLS, alone creates an end to end path with bandwidth reservations which guarantees the availability of resources to carry traffic of volume less than or equal to the reserved bandwidth, but MPLS is not aware of the DiffServ classes which considered as a disadvantage. This research project demonstrated the usefulness of combining DiffServ and MPLS in voice-enabled network to enhance voice quality by reducing end to end delay, jitter, and packet loss and proposed a method for analyzing voice applications’ requirements based in DiffServ-aware MPLS network

IP-based virtual private networks and proportional quality of service differentiation

IP-based virtual private networks (VPNs) have the potential of delivering cost-effective, secure, and private network-like services. Having surveyed current enabling techniques, an overall picture of IP VPN implementations is presented. In order to provision the equivalent quality of service (QoS) of legacy connection-oriented layer 2 VPNs (e.g., Frame Relay and ATM), IP VPNs have to overcome the intrinsically best effort characteristics of the Internet. Subsequently, a hierarchical QoS guarantee framework for IP VPNs is proposed, stitching together development progresses from recent research and engineering work. To differentiate IP VPN QoS, the proportional QoS differentiation model, whose QoS specification granularity compromises that of IntServ and Diffserv, emerges as a potential solution. The investigation of its claimed capability of providing the predictable and controllable QoS differentiation is then conducted. With respect to the loss rate differentiation, the packet shortage phenomenon shown in two classical proportional loss rate (PLR) dropping schemes is studied. On the pursuit of a feasible solution, the potential of compromising the system resource, that is, the buffer, is ruled out; instead, an enhanced debt-aware mechanism is suggested to relieve the negative effects of packet shortage. Simulation results show that debt-aware partially curbs the biased loss rate ratios, and improves the queueing delay performance as well. With respect to the delay differentiation, the dynamic behavior of the average delay difference between successive classes is first analyzed, aiming to gain insights of system dynamics. Then, two classical delay differentiation mechanisms, that is,proportional average delay (PAD) and waiting time priority (WTP), are simulated and discussed. Based on observations on their differentiation performances over both short and long time periods, a combined delay differentiation (CDD) scheme is introduced. Simulations are utilized to validate this method. Both loss and delay differentiations are based on a series of differentiation parameters. Though previous work on the selection of delay differentiation parameters has been presented, that of loss differentiation parameters mostly relied on network operators\u27 experience. A quantitative guideline, based on the principles of queueing and optimization, is then proposed to compute loss differentiation parameters. Aside from analysis, the new approach is substantiated by numerical results