An Application-aware SDN Controller for Hybrid Optical-electrical DC Networks

The adoption of optical switching technologies in Data Centre Networks (DCNs) offers a solution for high speed traffic and energy efficiency in Data Centre (DC) operational management, enabling an easy scaling of DC infrastructures. Flexible, slotted allocation of optical resources is fundamental to efficiently support the dynamicity of DC traffic. In this context, the NEPHELE project proposes a Time Division Multiple Access approach for optical resource allocation, orchestrated through a Software Defined Networking controller which coordinates the DCN configuration based on real-time cloud application requests

SLIP-IN architecture: a new hybrid optical switching scheme

In this paper, we present a new hybrid switching architecture, termed as SLIP-IN, that combines electronic packet/burst with optical circuit switching. SLIP-IN architecture takes advantages of the pre-transmission idle periods of optical lightpaths and slips into them packets or bursts of packets. In optical circuit switching (wavelength-routing) networks, capacity is immediately hard-reserved upon the arrival of a setup message, but is only used after a round-trip time delay. This idle period is significant for optical multi-gigabit networks and can be used to transmit traffic of a lower class of service. In this paper, we present the main features and dependencies of the proposed hybrid switching architecture, and further we perform a detailed evaluation by conducting network wide simulation experiments on the NSFnet backbone topology. For this purpose, we have developed an extensive network simulator, where the basic features of the architecture were modeled. The extensive network study revealed that SLIP-IN architecture can achieve and sustain an adequate data rate with a finite worst case delay

Resource partitioning in the NEPHELE datacentre interconnect

We present heuristic algorithms for the efficient resource partitioning in the NEPHELE datacentre optical interconnect. The algorithms aim to segment the network into smaller and isolated virtual datacentres (VDCs), where all racks are able to communicate at full capacity irrespective of their placement. Since the NEPHELE architecture relies on shared optical rings, the isolation of VDC traffic is challenging. Observing its close resemblance to finding a bi-clique on a bipartite graph, which is NP-hard, we propose heuristic algorithms which find a solution by limiting either the spatial spread of racks that construct each VDC or their wavelength allocation. If a solution cannot be found, then the algorithms invoke a second de-fragmentation phase, where they re-allocate the racks of existing VDCs to concentrate them spatially and reduce traffic on the shared optical rings. It is demonstrated via simulation that the proposed heuristics can achieve very high utilization and also exhibit low VDC request blocking probability for typically expected VDC sizes

SDN-enabled Application-aware networking for Datacenter networks

Software-Defined Networking (SDN) is a networking paradigm that decouples the control plane of a network from its forwarding plane and offers programmability of the data plane devices to manage and control the ongoing traffic flows. This paper presents the control plane architecture of a Datacentre network (DCN) and its operational services being developed for NEPHELEs optical network infrastructure. The heart of the proposed control plane overlay is an OpenDaylight SDN controller, which along-with its north and south-bound interfaces bridges the gap between the cloud applications and the DC network configuration at the data plane, in order to automatically adjust the underlying network to the Quality of Service (QoS) requirements at the application level. An application based traffic shaping use case is presented as a proof of concept of applicationaware networking in SDN-enabled data center networks

Experimental demonstration of a fully disaggregated and automated white box comprised of different types of transponders and monitors

White boxes, originally introduced in data centers, are expected to soon also penetrate the market of wide area networks, since operators see them as a way to drive down capital expenditure. Indeed, white boxes can be composed of modules from different vendors, removing the traditional vendor lock-in and creating more competition in the market, thus reducing hardware costs. In this paper, we describe the experimental demonstration of a fully disaggregated white box, composed of two different types of transponders, monitors (including filtering effect parameter monitors), add-drop multiplexers, and switches. Towards this end, we developed an appropriate control and management plane for the white box based on NETCONF and YANG. Using that, we demonstrated the automatic reconfiguration of the white box so as to maintain the service in the presence of multiple unexpected degradations: signal to noise ratio decrease and filtering distortion. We also demonstrated and presented here a vendor-neutral procedure to compute the thresholds used for raising alarms in response to physical layer degradations