Software Defined Networks based Smart Grid Communication: A Comprehensive Survey

The current power grid is no longer a feasible solution due to ever-increasing user demand of electricity, old infrastructure, and reliability issues and thus require transformation to a better grid a.k.a., smart grid (SG). The key features that distinguish SG from the conventional electrical power grid are its capability to perform two-way communication, demand side management, and real time pricing. Despite all these advantages that SG will bring, there are certain issues which are specific to SG communication system. For instance, network management of current SG systems is complex, time consuming, and done manually. Moreover, SG communication (SGC) system is built on different vendor specific devices and protocols. Therefore, the current SG systems are not protocol independent, thus leading to interoperability issue. Software defined network (SDN) has been proposed to monitor and manage the communication networks globally. This article serves as a comprehensive survey on SDN-based SGC. In this article, we first discuss taxonomy of advantages of SDNbased SGC.We then discuss SDN-based SGC architectures, along with case studies. Our article provides an in-depth discussion on routing schemes for SDN-based SGC. We also provide detailed survey of security and privacy schemes applied to SDN-based SGC. We furthermore present challenges, open issues, and future research directions related to SDN-based SGC.Comment: Accepte

On-board B-ISDN fast packet switching architectures. Phase 2: Development. Proof-of-concept architecture definition report

For the next-generation packet switched communications satellite system with onboard processing and spot-beam operation, a reliable onboard fast packet switch is essential to route packets from different uplink beams to different downlink beams. The rapid emergence of point-to-point services such as video distribution, and the large demand for video conference, distributed data processing, and network management makes the multicast function essential to a fast packet switch (FPS). The satellite's inherent broadcast features gives the satellite network an advantage over the terrestrial network in providing multicast services. This report evaluates alternate multicast FPS architectures for onboard baseband switching applications and selects a candidate for subsequent breadboard development. Architecture evaluation and selection will be based on the study performed in phase 1, 'Onboard B-ISDN Fast Packet Switching Architectures', and other switch architectures which have become commercially available as large scale integration (LSI) devices

Optical Multicast Routing Under Light Splitter Constraints

During the past few years, we have observed the emergence of new applications that use multicast transmission. For a multicast routing algorithm to be applicable in optical networks, it must route data only to group members, optimize and maintain loop-free routes, and concentrate the routes on a subset of network links. For an all-optical switch to play the role of a branching router, it must be equipped with a light splitter. Light splitters are expensive equipments and therefore it will be very expensive to implement splitters on all optical switches. Optical light splitters are only implemented on some optical switches. That limited availability of light splitters raises a new problem when we want to implement multicast protocols in optical network (because usual multicast protocols make the assumption that all nodes have branching capabilities). Another issue is the knowledge of the locations of light splitters in the optical network. Nodes in the network should be able to identify the locations of light splitters scattered in the optical network so it can construct multicast trees. These problems must be resolved by implementing a multicast routing protocol that must take into consideration that not all nodes can be branching node. As a result, a new signaling process must be implemented so that light paths can be created, spanning from source to the group members

SDNsec: Forwarding Accountability for the SDN Data Plane

SDN promises to make networks more flexible, programmable, and easier to manage. Inherent security problems in SDN today, however, pose a threat to the promised benefits. First, the network operator lacks tools to proactively ensure that policies will be followed or to reactively inspect the behavior of the network. Second, the distributed nature of state updates at the data plane leads to inconsistent network behavior during reconfigurations. Third, the large flow space makes the data plane susceptible to state exhaustion attacks. This paper presents SDNsec, an SDN security extension that provides forwarding accountability for the SDN data plane. Forwarding rules are encoded in the packet, ensuring consistent network behavior during reconfigurations and limiting state exhaustion attacks due to table lookups. Symmetric-key cryptography is used to protect the integrity of the forwarding rules and enforce them at each switch. A complementary path validation mechanism allows the controller to reactively examine the actual path taken by the packets. Furthermore, we present mechanisms for secure link-failure recovery and multicast/broadcast forwarding.Comment: 14 page

Towards all-optical label switching nodes with multicast

Fiber optics has developed so rapidly during the last decades that it has be- come the backbone of our communication systems. Evolved from initially static single-channel point-to-point links, the current advanced optical backbone net- work consists mostly of wavelength-division multiplexed (WDM) networks with optical add/drop multiplexing nodes and optical cross-connects that can switch data in the optical domain. However, the commercially implemented optical net- work nodes are still performing optical circuit switching using wavelength routing. The dedicated use of wavelength and infrequent recon¯guration result in relatively poor bandwidth utilization. The success of electronic packet switching has inspired researchers to improve the °exibility, e±ciency, granularity and network utiliza- tion of optical networks by introducing optical packet switching using short, local optical labels for forwarding decision making at intermediate optical core network nodes, a technique that is referred to as optical label switching (OLS). Various research demonstrations on OLS systems have been reported with transparent optical packet payload forwarding based on electronic packet label processing, taking advantage of the mature technologies of electronic logical cir- cuitry. This approach requires optic-electronic-optic (OEO) conversion of the op- tical labels, a costly and power consuming procedure particularly for high-speed labels. As optical packet payload bit rate increases from gigabit per second (Gb/s) to terabit per second (Tb/s) or higher, the increased speed of the optical labels will eventually face the electronic bottleneck, so that the OEO conversion and the electronic label processing will be no longer e±cient. OLS with label processing in the optical domain, namely, all-optical label switching (AOLS), will become necessary. Di®erent AOLS techniques have been proposed in the last ¯ve years. In this thesis, AOLS node architectures based on optical time-serial label processing are presented for WDM optical packets. The unicast node architecture, where each optical packet is to be sent to only one output port of the node, has been in- vestigated and partially demonstrated in the EU IST-LASAGNE project. This thesis contributes to the multicast aspects of the AOLS nodes, where the optical packets can be forwarded to multiple or all output ports of a node. Multicast capable AOLS nodes are becoming increasingly interesting due to the exponen- tial growth of the emerging multicast Internet and modern data services such as video streaming, high de¯nition TV, multi-party online games, and enterprise ap- plications such as video conferencing and optical storage area networks. Current electronic routers implement multicast in the Internet protocol (IP) layer, which requires not only the OEO conversion of the optical packets, but also exhaus- tive routing table lookup of the globally unique IP addresses. Despite that, there has been no extensive studies on AOLS multicast nodes, technologies and tra±c performance, apart from a few proof-of-principle experimental demonstrations. In this thesis, three aspects of the multicast capable AOLS nodes are addressed: 1. Logical design of the AOLS multicast node architectures, as well as func- tional subsystems and interconnections, based on state-of-the-art literature research of the ¯eld and the subject. 2. Computer simulations of the tra±c performance of di®erent AOLS unicast and multicast node architectures, using a custom-developed AOLS simulator AOLSim. 3. Experimental demonstrations in laboratory and computer simulations using the commercially available simulator VPItransmissionMakerTM, to evaluate the physical layer performance of the required all-optical multicast technolo- gies. A few selected multi-wavelength conversion (MWC) techniques are particularly looked into. MWC is an essential subsystem of the AOLS node for realizing optical packet multicast by making multiple copies of the optical packet all-optically onto di®er- ent wavelengths channels. In this thesis, theMWC techniques based on cross-phase modulation and four-wave mixing are extensively investigated. The former tech- nique o®ers more wavelength °exibility and good conversion e±ciency, but it is only applicable to intensity modulated signals. The latter technique, on the other hand, o®ers strict transparency in data rate and modulation format, but its work- ing wavelengths are limited by the device or component used, and the conversion e±ciency is considerably lower. The proposals and results presented in this thesis show feasibility of all-optical packet switching and multicasting at line speed without any OEO conversion and electronic processing. The scalability and the costly optical components of the AOLS nodes have been so far two of the major obstacles for commercialization of the AOLS concept. This thesis also introduced a novel, scalable optical labeling concept and a label processing scheme for the AOLS multicast nodes. The pro- posed scheme makes use of the spatial positions of each label bit instead of the total absolute value of all the label bits. Thus for an n-bit label, the complexity of the label processor is determined by n instead of 2n

Ethernet - a survey on its fields of application

During the last decades, Ethernet progressively became the most widely used local area networking (LAN) technology. Apart from LAN installations, Ethernet became also attractive for many other fields of application, ranging from industry to avionics, telecommunication, and multimedia. The expanded application of this technology is mainly due to its significant assets like reduced cost, backward-compatibility, flexibility, and expandability. However, this new trend raises some problems concerning the services of the protocol and the requirements for each application. Therefore, specific adaptations prove essential to integrate this communication technology in each field of application. Our primary objective is to show how Ethernet has been enhanced to comply with the specific requirements of several application fields, particularly in transport, embedded and multimedia contexts. The paper first describes the common Ethernet LAN technology and highlights its main features. It reviews the most important specific Ethernet versions with respect to each application field’s requirements. Finally, we compare these different fields of application and we particularly focus on the fundamental concepts and the quality of service capabilities of each proposal

Measurement-Driven Algorithm and System Design for Wireless and Datacenter Networks

The growing number of mobile devices and data-intensive applications pose unique challenges for wireless access networks as well as datacenter networks that enable modern cloud-based services. With the enormous increase in volume and complexity of traffic from applications such as video streaming and cloud computing, the interconnection networks have become a major performance bottleneck. In this thesis, we study algorithms and architectures spanning several layers of the networking protocol stack that enable and accelerate novel applications and that are easily deployable and scalable. The design of these algorithms and architectures is motivated by measurements and observations in real world or experimental testbeds. In the first part of this thesis, we address the challenge of wireless content delivery in crowded areas. We present the AMuSe system, whose objective is to enable scalable and adaptive WiFi multicast. AMuSe is based on accurate receiver feedback and incurs a small control overhead. This feedback information can be used by the multicast sender to optimize multicast service quality, e.g., by dynamically adjusting transmission bitrate. Specifically, we develop an algorithm for dynamic selection of a subset of the multicast receivers as feedback nodes which periodically send information about the channel quality to the multicast sender. Further, we describe the Multicast Dynamic Rate Adaptation (MuDRA) algorithm that utilizes AMuSe's feedback to optimally tune the physical layer multicast rate. MuDRA balances fast adaptation to channel conditions and stability, which is essential for multimedia applications. We implemented the AMuSe system on the ORBIT testbed and evaluated its performance in large groups with approximately 200 WiFi nodes. Our extensive experiments demonstrate that AMuSe can provide accurate feedback in a dense multicast environment. It outperforms several alternatives even in the case of external interference and changing network conditions. Further, our experimental evaluation of MuDRA on the ORBIT testbed shows that MuDRA outperforms other schemes and supports high throughput multicast flows to hundreds of nodes while meeting quality requirements. As an example application, MuDRA can support multiple high quality video streams, where 90% of the nodes report excellent or very good video quality. Next, we specifically focus on ensuring high Quality of Experience (QoE) for video streaming over WiFi multicast. We formulate the problem of joint adaptation of multicast transmission rate and video rate for ensuring high video QoE as a utility maximization problem and propose an online control algorithm called DYVR which is based on Lyapunov optimization techniques. We evaluated the performance of DYVR through analysis, simulations, and experiments using a testbed composed of Android devices and o the shelf APs. Our evaluation shows that DYVR can ensure high video rates while guaranteeing a low but acceptable number of segment losses, buffer underflows, and video rate switches. We leverage the lessons learnt from AMuSe for WiFi to address the performance issues with LTE evolved Multimedia Broadcast/Multicast Service (eMBMS). We present the Dynamic Monitoring (DyMo) system which provides low-overhead and real-time feedback about eMBMS performance. DyMo employs eMBMS for broadcasting instructions which indicate the reporting rates as a function of the observed Quality of Service (QoS) for each UE. This simple feedback mechanism collects very limited QoS reports which can be used for network optimization. We evaluated the performance of DyMo analytically and via simulations. DyMo infers the optimal eMBMS settings with extremely low overhead, while meeting strict QoS requirements under different UE mobility patterns and presence of network component failures. In the second part of the thesis, we study datacenter networks which are key enablers of the end-user applications such as video streaming and storage. Datacenter applications such as distributed file systems, one-to-many virtual machine migrations, and large-scale data processing involve bulk multicast flows. We propose a hardware and software system for enabling physical layer optical multicast in datacenter networks using passive optical splitters. We built a prototype and developed a simulation environment to evaluate the performance of the system for bulk multicasting. Our evaluation shows that the optical multicast architecture can achieve higher throughput and lower latency than IP multicast and peer-to-peer multicast schemes with lower switching energy consumption. Finally, we study the problem of congestion control in datacenter networks. Quantized Congestion Control (QCN), a switch-supported standard, utilizes direct multi-bit feedback from the network for hardware rate limiting. Although QCN has been shown to be fast-reacting and effective, being a Layer-2 technology limits its adoption in IP-routed Layer 3 datacenters. We address several design challenges to overcome QCN feedback's Layer- 2 limitation and use it to design window-based congestion control (QCN-CC) and load balancing (QCN-LB) schemes. Our extensive simulations, based on real world workloads, demonstrate the advantages of explicit, multi-bit congestion feedback, especially in a typical environment where intra-datacenter traffic with short Round Trip Times (RTT: tens of s) run in conjunction with web-facing traffic with long RTTs (tens of milliseconds)