Distributed Control Plane Research Articles

Relationship-Oriented Software Defined AS-Level Fast Rerouting for Multiple Link Failures

Large-scale deployments of mission-critical services have led to stringent demands on Internet routing, but frequently occurring network failures can dramatically degrade the network performance. However, Border Gateway Protocol (BGP) can not react quickly to recover from them. Although extensive research has been conducted to deal with the problem, the multiple failure scenarios have never been properly addressed due to the limit of distributed control plane. In this paper, we propose a local fast reroute approach to effectively recover from multiple link failures in one administrative domain. The principle of Software Defined Networking (SDN) is used to achieve the software defined AS-level fast rerouting. Considering AS relationships, efficient algorithms are proposed to automatically and dynamically find protection paths for multiple link failures; then OpenFlow forwarding rules are installed on routers to provide data forwarding continuity. Our approach is able to ensure applicability to ASes with flexibility and adaptability to multiple link failures, contributing toward improving the network performance. Through experimental results, we show that our proposal provides effective failure recovery and does not introduce significant control overhead to the network.

Software-Defined Networking: Challenges and research opportunities for Future Internet

Currently many aspects of the classical architecture of the Internet are etched in stone – a so called ossification of the Internet – which has led to major obstacles in IPv6 deployment and difficulty in using IP multicast services. Yet, there exist many reasons to extend the Internet, e.g., for improving intra-domain and inter-domain routing for high availability of the network, providing end-to-end connectivity for users, and allowing dynamic QoS management of network resources for new applications, such as data center, cloud computing, and network virtualization. To address these requirements, the next-generation architecture for the Future Internet has introduced the concept of Software-Defined Networking (SDN). At the core of this emerging paradigm is the separation and centralization of the control plane from the forwarding elements in the network as opposed to the distributed control plane of existing networks. This decoupling allows deployment of control plane software components (e.g., OpenFlow controller) on computer platforms that are much more powerful than traditional network equipment (e.g., switches/routers) while protecting the data and intellectual property of the vendors of such equipment.A critical understanding of this emerging paradigm is necessary to address the multiple challenges in realizing the Future Internet and to resolve the ossification problem of the existing Internet. To address these requirements, this paper surveys existing technologies and the wide range of recent and state-of-the-art projects on SDN followed by an in-depth discussion of the major challenges in this area.

Distributed QoS Architectures for Multimedia Streaming Over Software Defined Networks

This paper presents novel QoS extensions to distributed control plane architectures for multimedia delivery over large-scale, multi-operator Software Defined Networks (SDNs). We foresee that large-scale SDNs shall be managed by a distributed control plane consisting of multiple controllers, where each controller performs optimal QoS routing within its domain and shares summarized (aggregated) QoS routing information with other domain controllers to enable inter-domain QoS routing with reduced problem dimensionality. To this effect, this paper proposes (i) topology aggregation and link summarization methods to efficiently acquire network topology and state information, (ii) a general optimization framework for flow-based end-to-end QoS provision over multi-domain networks, and (iii) two distributed control plane designs by addressing the messaging between controllers for scalable and secure inter-domain QoS routing. We apply these extensions to streaming of layered videos and compare the performance of different control planes in terms of received video quality, communication cost and memory overhead. Our experimental results show that the proposed distributed solution closely approaches the global optimum (with full network state information) and nicely scales to large networks.

Dynamic and Adaptive Control Plane Solutions for Flexi-Grid Optical Networks Based on Stateful PCE

Adaptive flexi-grid optical networks should be able to autonomously decide where and when to dynamically setup, reoptimize, and release elastic optical connections, in reaction to network state changes. A stateful path computation element (PCE) is a key element for the introduction of dynamics and adaptation in generalized multiprotocol label switching (GMPLS)-based distributed control plane for flexi-grid DWDM networks (e.g., global concurrent reoptimization, defragmentation, or elastic inverse-multiplexing), as well as for enabling the standardized deployment of the GMPLS control plane in the software defined network control architecture. First, this paper provides an overview of passive and active stateful PCE architectures for GMPLS-enabled flexi-grid DWDM networks. A passive stateful PCE allows for improved path computation considering not only the network state (TED) but also the global connection state label switched paths database (LSPDB), in comparison with a (stateless) PCE. However, it does not have direct control (modification, rerouting) of path reservations stored in the LSPDB. The lack of control of these label switched paths (LSPs) may result in the suboptimal performance. To this end, an active stateful PCE allows for optimal path computation considering the LSPDB for the control of the state (e.g., increase of LSP bandwidth, LSP rerouting) of the stored LSPs. More recently, an active stateful PCE architecture has also been proposed that exposes the capability of setting up and releasing new LSPs. It is known as active stateful PCE with instantiation capabilities. This paper presents the first prototype implementation and experimental evaluation of an active stateful PCE with instantiation capabilities for the GMPLS-controlled flexi-grid DWDM network of the ADRENALINE testbed.

The deployment of routing protocols in distributed control plane of SDN.

Software defined network (SDN) provides a programmable network through decoupling the data plane, control plane, and application plane from the original closed system, thus revolutionizing the existing network architecture to improve the performance and scalability. In this paper, we learned about the distributed characteristics of Kandoo architecture and, meanwhile, improved and optimized Kandoo's two levels of controllers based on ideological inspiration of RCP (routing control platform). Finally, we analyzed the deployment strategies of BGP and OSPF protocol in a distributed control plane of SDN. The simulation results show that our deployment strategies are superior to the traditional routing strategies.

Scalable Optical Interconnect Architecture Using AWGR-Based TONAK LION Switch With Limited Number of Wavelengths

This paper analyzes the scalability in arrayed waveguide grating router (AWGR)-based interconnect architectures and demonstrates active AWGR-based switching using a distributed control plane. First, the paper analyses an all-to-all single AWGR passive interconnection with N nodes and proposes a new architecture that overcomes the scalability limitation given by wavelength registration and crosstalk, by introducing multiples of smaller AWGRs (W × W) operating on a fewer number of wavelengths . Second, this paper demonstrates active AWGR switching with a distributed control plane, to be used when the size of the interconnection network makes the all-to-all approach using passive AWGRs impractical. In particular, an active AWGR-based TONAK switch is introduced. TONAK combines an all-optical NACK technique, which removes the need for electrical buffers at the switch input/output ports, and a TOKEN technique, which enables a distributed all-optical arbiter to handle packet contention. The experimental validation and performance study of the AWGR-based TONAK switch is presented, demonstrating the feasibility of the TONAK solution and the high throughput and low average packet latency for an up to 75% offered load.

Applications and Status of Path Computation Elements [Invited

In any dynamic control plane architecture targeting connection-oriented networks, the path computation function can be defined as the one that deals with obtaining a route for a given request or, equivalently, with finding appropriate resources to be allocated to new incoming flows within the network, given the knowledge of the network status, its topology and resource availability, and the applicable constraints and policies. The path computation function can be located in a network management system or in one or more network elements. In the scope of a distributed control plane such as multiprotocol label switching (MPLS) and generalized MPLS, such a function is commonly located either in a process running on each node controller (referred to as source routing) or deployed using a dedicated entity. To this end, the Internet Engineering Task Force defines a path computation element (PCE) as a control plane functional component which is able to perform constrained path computation on a graph representing a network. This paper provides an overview of PCEs and elaborates on selected aspects regarding the deployment and use of PCEs as a functional element in the framework of control and management of optical networks, highlighting the motivations behind their adoption, common deployment models, and related testbed experimentation. The paper also briefly explores new trends such as the extensions for the so-called stateful PCEs and the role of PCEs in software defined networks.

Dynamic and fair resource allocation in a distributed ring-based WDM-PON architectures

The overall objective of this paper is to propose and devise a dynamic and fair resource allocation technique in a ring-based WDM-PON architecture with truly shared LAN capabilities among end-users. A new distributed control plane is developed for this architecture that enables intercommunication among the ONUs, as well as signaling and scheduling procedures that operate in a distributed manner. To cope with the unpredictable users’ behavior and bandwidth demands, which shift both in time and place in such a networking environment, supported by the devised control plane, a distributed and efficient network resource allocation and sharing strategy is developed allowing for efficient dynamic allocation and sharing of overall downstream, upstream, and LAN network resources by adaptively adjusting them to the offered load. Performance results concerning link throughput and delay are presented, validating that the proposed methodology can meet the capacity requirements of the dynamic and highly fluctuant traffic pattern of the emerging multimedia applications and services. Specifically, the simulation results clearly show the effectiveness of the proposed shared wavelength strategy as the downstream/upstream network throughput is almost equal to the ideal theoretical throughput.

A Fully Distributed 10G-EPON-based Converged Fixed–Mobile Networking Transport Infrastructure for Next Generation Broadband Access

This work proposes and devises a self-healing hybrid tree/ring-based 10G-EPON architecture that enables the support of a converged PON-4G LTE access networking transport infrastructure to seamlessly backhaul both mobile and wireline business and residential services. The salient feature of the proposed architecture is that it supports a fully distributed control plane that enables intercommunication among the access nodes (optical network units - ONUs) as well as signaling, scheduling algorithms, and fault detection and recovery mechanisms. The distributed control plane enables each and every ONU to independently detect, manage, and recover most of the networking failure scenarios. This paper outlines and addresses the key technical requirements and differences between a PON-based converged architecture that utilizes a typically centralized architecture as the wireless segment of the hybrid architecture (e.g., Wi-Fi) versus one which utilizes a fully distributed architecture (e.g., 4G LTE). Physical layer performance simulations for the proposed architecture are also presented that show error free performance for the scalable architecture.

New Technologies and Directions for the Optical Control Plane

Distributed control plane technology has been incorporated in many carrier optical networks to improve automation, robustness, and efficiency. Going forward, carriers' interest is shifting from internal domain protocols to interdomain interfaces. Also, new transport technologies being deployed such as optical transport network, packet, and photonic transport need control plane support, while new technologies are being added to the control plane itself, especially path computation elements and multilayer integration tools.

Novel path computation element-based traffic grooming strategy in Internet protocol over wavelength division multiplexing networks

With the emergence of various broadband services, a lot of bandwidth fragments will be generated during the operation of services being mapped into optical channels, which will waste too many bandwidth resources and decrease the transmission performance of optical networks. Traffic grooming strategy in dynamic optical networks can optimise the utilisation of bandwidth resources and reduce the blocking probability. However, in the distributed control plane of automated switched optical networks, all the traffic grooming strategies are implemented in each control node, and resource collision will still occur because the same link resource may be used by two path computation requests or traffic engineering information flooded by open shortest path first-traffic engineering protocol may be not synchronous at each control node or signalling delay time is too long. To reduce the collision of resource, a unified control plane is designed based on path computation element (PCE) for Internet protocol over wavelength division multiplexing networks, and a novel PCE-based traffic grooming strategy is proposed in the framework of unified control plane. Based on this strategy, four PCE-based traffic grooming algorithms are proposed and compared with the distributed traffic grooming strategy without PCE on a simulation platform implemented using disperse event simulation tool OMNET++.

Experimental Demonstration of an Impairment Aware Network Planning and Operation Tool for Transparent/Translucent Optical Networks

Core optical networks using reconfigurable optical switches and tunable lasers appear to be on the road towards widespread deployment and could evolve to all-optical mesh networks in the coming future. Considering the impact of physical layer impairments in the planning and operation of all-optical (and translucent) networks is the main focus of the Dynamic Impairment Constraint Optical Networking (DICONET) project. The impairment aware network planning and operation tool (NPOT) is the main outcome of DICONET project, which is explained in detail in this paper. The key building blocks of the NPOT, consisting of network description repositories, the physical layer performance evaluator, the impairment aware routing and wavelength assignment engines, the component placement modules, failure handling, and the integration of NPOT in the control plane are the main contributions of this study. Besides, the experimental result of DICONET proposal for centralized and distributed control plane integration schemes and the performance of the failure handling in terms of restoration time is presented in this study.

Distributed Control Plane: Adaptive Load Balancing for Parallel BGP Route Computing

The high scalability of next generation Internet supports deploying Internet services dynamically.With the deployment of more and more delay-and jitter-sensitive applications such as IPTV and VoIP,more route processing power is required to improve the performance of BGP route selection.Routers adopt distributed control planes and implement parallel BGP route processing,which is a potential approach to overcome the bottleneck of centralized control planes and improve the performance of route computation.However,current BGP parallel route computing schemes cannot keep load balance well,which degrades the performance of parallel route computing.In this paper,a load balance model for parallel BGP route computing is proposed based on hashing.Through accumulating prefix updates online and reallocating them among all processing nodes adaptively,the authors propose P-AP(Prediction-based Adaptive Partition)algorithm for parallel BGP route computation,design and implement the prototype of load balancing for parallel BGP route computation.Route Views BGP Update dataset is used to verify the performance of P-AP algorithm.Experimental results show that P-AP algorithm can balance load well among all processing nodes,minimize load adjusting,and have the maximum speedup of route computation.It can effectively improve the performance of parallel BGP route computing.

A novel medium access control protocol for passive optical network supporting local area networking capabilities

An alternate solution for Ethernet passive optical networks (EPON) providing local area networking (LAN) capabilities is proposed in this article. Our solution adopts a star coupler-based PON architecture and uses radio frequency subcarrier multiplexed transmission for the LAN traffic delivery. The proposed medium access control (MAC) protocol supports a fully distributed control plane among the optical network units (ONUs) for ONU---ONU communication as well as upstream access to the OLT. The simulation results indicate that the proposed MAC protocol outperforms the others in terms of the average packet end-to-end delay, especially for LAN traffic.

An ant-based algorithm for distributed routing and wavelength assignment in dynamic optical networks

Future optical communication networks are expected to change radically during the next decade. To meet the demanded bandwidth requirements, more dynamism, scalability and automatism will need to be provided. This will also require addressing issues such as the design of highly distributed control plane systems and their associated algorithms to respond to network changes very rapidly. In this work, we propose the use of an ant colony optimization (ACO) algorithm to solve the intrinsic problem of the routing and wavelength assignment (RWA) on wavelength continuity constraint optical networks. The main advantage of the protocol is its distributed nature, which provides higher survivability to network failures or traffic congestion. The protocol has been applied to a specific type of future optical network based on the optical switching of bursts. It has been evaluated through extensive simulations with very promising results, particularly on highly congested scenarios where the load balancing capabilities of the protocol become especially efficient. Results on a partially meshed network like NSFNET show that the ant-based protocol outperforms other RWA algorithms under test in terms of blocking probability without worsening other metrics such as mean route length.

Effects of Outdated Control Information in Control-Plane-Enabled Optical Networks With Path Protection

New signaling suites for a distributed control plane in wavelength division multiplexing (WDM) networks, such as generalized multiprotocol label switching (GMPLS) and automatic switched optical networks (ASON), allow one to cope with the increasing variability of traffic patterns to be suppor ted by operators by providing a means to dynamically set up and release connections. The dissemination of link-state information [usually provided by routing protocols such as open-shortest-path-first traffic engineering (OSPF-TE)] is essential in this kind of control-plane enabled network: in particular, this information has to be continuously updated to allow routing algorithms to efficiently carry out the path computation. Most of the studies on dynamic traffic routing tend to neglect the effect of delays in control-information distribution on routing performance: in particular, even when the control plane is considered as in testbeds, emulators, or some simulations, the analysis of the effects of control plane delays is limited to a small range of values, applicable to well-specified contexts. Applying a very general control-delay representation, we are able to provide a wide-range simulative study to quantify the effect of sig naling on routing performance, mainly by using the blocking probability metric. We are able to evaluate the effect of outdated information (1) for a wide interval of control delay values, (2) for a large set of routing scenarios, considering, e.g., unprotected, dedica ted, and shared path protection routing, and (3) quan tifying the different delay effects in the absence or in the presence of wavelength conversion capabilities.

Topology-Information Periodic Updates in Multi-Domain ASON Networks with Topology Aggregation

Thanks to the development of the automatic and distributed control plane (ASON and GMPLS standards), optical transport networks are able to provide bandwidth-on-demand services quickly and efficiently. But for these services to be really interesting to users, the capability of seamlessly operating the network across multiple administrative domains should be developed. Multi-domain routing in ASON is a new challenging topic, especially if the target is a scalable solution. This article investigates, in particular, the application of aggregation topology methods to the representation of network domains in a dynamic scenario. These methods, initially devised for the ATM networks, can be extended to ASON/GMPLS, as recommended by the Optical Interworking Forum (OIF). Topology aggregation limits the amount of topology information distributed throughout the network and the bandwidth occupation for control plane signaling, improving scalability. Besides this partial distribution of information, in a real network the update of the distributed topology databases to the changes of state is not instantaneous, but it occurs with some delay. In this article, we evaluate the combined effect of topology aggregation and non-instantaneous topology information update on the routing performance of a multi-domain network. This study assumes that information updating is periodic, with different durations of the period. Moreover, we will refer to the topology-aggregation methods proposed by OIF (full mesh and symmetric star) in addition to a hybrid method proposed in this article.

Survivable broadband local access PON architecture: a new direction for supporting simple and efficient resilience capabilities

This work proposes a two-fiber self-healing ring-based local access passive optical network (PON) architecture that addresses some of the limitations of current tree-based PON architectures including supporting private networking capability as well as providing simple and cost-effective fully distributed resilience capabilities against most kinds of networking failures. Specifically, this work proposes and devises a simple self-healing Ethernet PON architecture that supports a truly shared LAN capability among end users. The main characteristic of the proposed architecture is that it supports a fully distributed control plane among the optical network units (ONUs) for ONU-to-ONU communication. The control plane supports fully distributed fault detection and recovery mechanisms as well as a decentralized dynamic bandwidth allocation scheme in which the optical line terminator is excluded from both the bandwidth arbitration and fault detection and recovery processes. The proposed decentralized automatic protection switching technique is capable of protecting against both node (ONU) and fiber failures (distribution and trunk) through active participation of ONUs. This scheme enables the recovery of all network traffic including upstream, downstream, and LAN data. In addition, the proposed protection technique can protect against any combination of concurrent double failures including trunk and distribution fiber breaks and node failures.

Impact of routing and wavelength selection strategies on GMPLS-controlled distributed restoration

The restorability problem in wavelength-routed networks without wavelength converters is investigated. A distributed control plane based on the generalized multiprotocol label switching (GMPLS) suite is considered for disseminating link-state information and reserving network resources. Different routing and wavelength selection strategies are proposed and a detailed performance analysis is carried out during restoration. Simulation results evaluate the blocking probability due to both lack of available resources (i.e., forward blocking) and resource contentions (i.e., backward blocking). Performance comparison provides some insightful suggestions to be applied to GMPLS-controlled wavelength-routed networks without wavelength converters. First, it is recommended to perform routing and wavelength selection separately at the lightpath source and destination, respectively. Second, routing can be computed on link-state information advertised during provisioning, without the need of flooding link-state information during restoration. In fact, during restoration, the resource contention among concurrent signaling instances is the dominant cause of blocking (i.e., backward blocking overcomes forward blocking). For this reason, intelligent routing and wavelength selection strategies aiming at avoiding or limiting resource contentions can help to improve restorability. In particular, among those strategies, the proposed wavelength selection has a better ability to reduce resource contentions than the routing strategies.

Managing Layer 1 VPN services

Control Plane architectures enhance transport networks with distributed signaling and routing mechanisms which allow dynamic connection control. As a result, layer 1 switching networks enabled with a distributed control plane can support the provisioning of advanced connectivity services like Virtual Private Networks (VPNs). Such Layer 1 VPN (L1VPN) service allows multiple customer networks to share a single transport network in a cost-effective way. However, L1VPN deployment still faces many challenges. In this work, we are concerned on configuration management and interdomain provisioning of L1VPN services. We propose an L1VPN management architecture based on the Policy-Based Management (PBM) approach. First, we describe the architecture and how it allows a single service provider to support multiple L1VPNs while providing customers with some level of control over their respective service. Then we explain how the architecture was extended to support interdomain L1VPNs by using the Virtual Topology approach. We also discuss the prototype implementation and evaluation of the proposed architecture. Moreover, this work is a tentative note before raising a more deep discussion related to interdomain provisioning of L1VPN services and implications of a policy-based approach for L1VPN configuration management.