Metro and carrier-grade Ethernet networks, as well as industrial area networks and specific local area networks (LANs), have to guarantee fast resiliency upon network failure. However, the current OpenFlow architecture, originally designed for LANs, does not include effective mechanisms for fast resiliency. In this paper, the OpenFlow architecture is enhanced to support segment protection in Ethernet-based networks. Novel mechanisms have been specifically introduced to maintain working and backup flows at different priorities and to guarantee effective network resource utilization when the failed link is recovered. Emulation and experimental demonstration implementation results show that the proposed architecture avoids both the utilization of a full-state controller and the intervention of the controller upon failure, thus guaranteeing a recovery time only due to the failure detection time, i.e., a few tens of milliseconds within the considered scenario.

No abstract

Abstract-Network slices combine resource virtualization with the isolation level required by future 5G applications. In addition, the use of monitoring and data analytics help to maintain the required network performance, while reducing total cost of ownership. In this paper, an architecture to enable autonomic slice networking is presented. Extended nodes make local decisions close to network devices, whereas centralized domain systems collate and export metered data transparently to customer controllers, all of them leveraging customizable and isolated data analytics processes. Discovered knowledge can be applied for both proactive and reactive network slice reconfiguration, triggered either by service providers or customers, thanks to the interaction with state-of-the-art software-defined networking controllers and planning tools. The architecture is experimentally demonstrated by means of a complex use case for a multi-domain multilayer MPLS-overoptical network. In particular, the use case consists of the following Observe-Analyze-Act loops: i) proactive network slice rerouting after BER degradation detection in a lightpath supporting a virtual link (vlink); ii) reactive core network restoration after optical link failure; and iii) reactive network slice rerouting after the degraded lightpath is restored. The proposed architecture is experimentally validated on a distributed testbed connecting premises in UPC (Spain) and CNIT (Italy).

Quality of Service-enabled applications and services rely on Traffic Engineering-based (TE) Label Switched Paths (LSP) established in core networks and controlled by the GMPLS control plane. Path computation process is crucial to achieve the desired TE objective. Its actual effectiveness depends on a number of factors. Mechanisms utilized to update topology and TE information, as well as the latency between path computation and resource reservation, which is typically distributed, may affect path computation efficiency. Moreover, TE visibility is limited in many network scenarios, such as multi-layer, multidomain and multi-carrier networks, and it may negatively impact resource utilization. The Internet Engineering Task Force (IETF) has promoted the Path Computation Element (PCE) architecture, proposing a dedicated network entity devoted to path computation process. The PCE represents a flexible instrument to overcome visibility and distributed provisioning inefficiencies. Communications between path computation clients (PCC) and PCEs, realized through the PCE Protocol (PCEP), also enable inter-PCE communications offering an attractive way to perform TE-based path computation among cooperating PCEs in multi-layer/domain scenarios, while preserving scalability and confidentiality. This survey presents the state-of-the-art on the PCE architecture for GMPLS-controlled networks carried out by research and standardization community. In this work, packet (i.e., MPLS-TE and MPLS-TP) and wavelength/spectrum (i.e., WSON and SSON) switching capabilities are the considered technological platforms, in which the PCE is shown to achieve a number of evident benefits.

Next generation optical networks will require high levels of flexibility both at the data and control planes, being able to fit rate, bandwidth, and optical reach requirements of different connections. Optical transmission should be able to support very high rates (e.g., 1 Tb/s) and to be distance adaptive while optimizing spectral efficiency (i.e., the information rate transmitted over a given bandwidth). Similarly, the control plane should be capable of performing effective routing and spectrum assignment as well as proper selection of the transmission parameters (e.g., modulation format) depending on the required optical reach. In this paper we present and demonstrate a software-defined super-channel transmission based on time frequency packing and on the proposed differentiated filter configuration. Time frequency packing is a technique able to achieve high spectral efficiency even with low-order modulation formats (e.g., quadrature phaseshift keying). It consists in sending pulses that overlap in time or frequency or both to achieve high spectral efficiency. Coding and detection are properly designed to account for the introduced inter-symbol and inter-carrier interference. We present a Software Defined Network (SDN) controller that sets transmission parameters (e.g., code rate) both at the transmitter and the receiver side. In particular, at the transmitter side, a programmable encoder adding redundancy to the data is controlled by SDN. At the receiver side, the digital signal processing is set by SDN based on the selected transmission parameters (e.g., code rate). Thus, extensions to the OpenFlow architectures are presented to control super-channel transmission based on time frequency packing. Then, the SDN-based differentiated filter configuration (DFC) is proposed. According to DFC, the passband of the filters traversed by the same connection can be configured to different values. Experiments including data and control planes are shown to demonstrate the feasibility of optical-reach-adaptive super-channel at 1 Tb/s controlled by extended OpenFlow. Then, the effectiveness of the proposed SDN-based DFC is demonstrated in a testbed with both wavelength selective switches and spectrum selective switches, where filters traversed by a connection requires different passband values. Extended OpenFlow messages for time frequency packing and supporting DFC have been captured and shown in the paper.