A Unified Software Architecture to Enable Cross-Layer Design in the Future Internet

Abstract—While research on cross-layer network optimization has been progressing, useful implementations have been lagging because the current Internet architecture does not accommodate cross-layering gracefully. As part of our FIND project, we propose a software architecture for the future Internet that is designed to accommodate such interactions. We present a conceptual overview as well as high level software design and an early prototype implementation, and point out the strengths of our architecture. I

JumpStart: A Just-in-Time Signaling Architecture for WDM Burst-Switched Networks

We present an architecture for a core dWDM network which utilizes the concept of optical burst switching coupled with a just-in-time signaling scheme. It is a reservation-based architecture whose distinguishing characteristics are its relative simplicity, its amenability to hardware implementation, and the ability to support multicast natively. Another important feature is data transparency --- the network infrastructure is independent of the format of the data being transmitted on individual wavelengths. We present the signaling protocol designed for this architecture, as well as an unified signaling message structure to be used in conjunction with the protocol. We also present the future directions of this research

Dynamic Reconfiguration Policies for WDM Networks

We study the issues arising when considering the problem of reconfiguring broadcast optical networks in response to changes in the traffic patterns. Although the ability to dynamically optimize the network under changing traffic conditions has been recognized as one of the key features of multiwavelength optical networks, this is the first in-depth study of the tradeoffs involved in carrying out the reconfiguration process. We first identify the degree of load balancing and the number of retunings as two important, albeit conflicting, objectives in the design of reconfiguration policies. We then formulate the problem as a Markovian Decision Process and we develop a systematic and flexible framework in which to study reconfiguration policies. We apply results from Markov Decision Process theory to obtain optimal reconfiguration policies for networks of large size. The advantages of optimal policies over a class of threshold-based policies are illustrated through numerical results. 1 In..

Reconfiguration and Dynamic Load Balancing in Broadcast WDM Networks

In optical WDM networks, an assignment of transceivers to channels implies an allocation of the bandwidth to the various network nodes. Intuition suggests, and our recent study has con®rmed, that if the traffic load is not well balanced across the available channels, the result is poor network performance. Hence, the time-varying conditions expected in this type of environment call for mechanisms that periodically adjust the bandwidth allocation to ensure that each channel carries an almost equal share of the corresponding offered load. In this paper we study the problem of dynamic load balancing in broadcast WDM networks by retuning a subset of transceivers in response to changes in the overall traffic pattern. Assuming an existing wavelength assignment and some information regarding the new traf®c demands, we present two approaches to obtaining a new wavelength assignment such that (a) the new traffic load is balanced across the channels, and (b) the number of transceivers that need to be retuned is minimized. The latter objective is motivated by the fact that tunable transceivers take a non-negligible amount of time to switch between wavelengths during which parts of the network are unavailable for normal operation. Furthermore, this variation in traffic is expected to take place over larger time scales (i.e., retuning will be a relatively infrequent event), making slowly tunable devices a cost effective solution. Our main contribution is a new approximation algorithm for the load balancing problem that provides for tradeoff selection, using a single parameter, between two conflicting goals, namely, the degree of load balancing and the number of transceivers that need to be retuned. This algorithm leads to a scalable approach to reconfiguring the network since, in addition to providing guarantees i

Reconfiguration in Rapidly Tunable Transmitter, Slowly Tunable Receiver Single-Hop WDM Networks

We consider broadcast WDM networks with nodes equipped with rapidly tunable transmitters and slowly tunable receivers. The rapidly tunable transmitters provide all-optical paths among the network nodes by creating logical connections that can be changed on a packet-by-packet basis. The ability of receivers to tune, albeit slowly, is invoked only for reallocating the bandwidth in response to changes in the overall traffic pattern. Since this variation in traffic is expected to take place over larger time scales, receiver retuning will be a relatively infrequent event, making slowly tunable devices a cost effective solution. Assuming an existing assignment of receive wavelengths and some information regarding the new traffic demands, we present two approaches to obtaining a new wavelength assignment such that (a) the new traffic load is balanced across the channels, and (b) the number of receivers that need to be retuned is minimized. One of our contributions is an approximation algorith..

Converging Choice and Service in Future Commodity Optical Networks using Traffic Grooming

The problem of providing an agile, energy-aware, flexible optical network architecture is one of the challenges in optical networking in the coming decade. A key element in this challenge is the balancing of the benefits to customer and provider, and creating an agile system capable of reflecting both provider and customer interests on an ongoing basis as network conditions change. In this paper, we articulate how the traditional optical networking research area of traffic grooming may be combined with recent advances in Internet architecture, specifically a proposed Future Internet architecture called ChoiceNet, and empowered by the recently emerged concept of software defined networking, to make some key contributions to this problem. I

A new internet architecture to enable software defined optics and evolving optical switching models

The design of the SILO network architecture of fine-grain services was based on three fundamental principles. First, SILO generalizes the concept of layering and decouples layers from services, making it possible to introduce easily new functionality and innovations into the architecture. Second, cross-layer interactions are explicitly supported by extending the definition of a service to include control interfaces that can be tuned externally so as to modify the behavior of the service. The third principle is “design for change: ” the architecture does not dictate the services to be implemented, but provides mechanisms to introduce new services and compose them to perform specific communication tasks. In this paper, we provide an update on the current status of the architecture and the prototype software implementation. We also introduce the concept of “software defined optics ” (SDO) to refer to the emerging intelligent and programmable optical layer. We then explain how the SILO architecture may enable the rapid adoption of SDO functionality as well as evolving optical switching models, in particular, optical burst switching (OBS)