The Internet has led to the creation of a digital society, where (almost) everything is connected and is accessible from anywhere. However, despite their widespread adoption, traditional IP networks are complex and very hard to manage. It is both difficult to configure the network according to predefined policies, and to reconfigure it to respond to faults, load, and changes. To make matters even more difficult, current networks are also vertically integrated: the control and data planes are bundled together. Software-defined networking (SDN) is an emerging paradigm that promises to change this state of affairs, by breaking vertical integration, separating the network's control logic from the underlying routers and switches, promoting (logical) centralization of network control, and introducing the ability to program the network. The separation of concerns, introduced between the definition of network policies, their implementation in switching hardware, and the forwarding of traffic, is key to the desired flexibility: by breaking the network control problem into tractable pieces, SDN makes it easier to create and introduce new abstractions in networking, simplifying network management and facilitating network evolution. In this paper, we present a comprehensive survey on SDN. We start by introducing the motivation for SDN, explain its main concepts and how it differs from traditional networking, its roots, and the standardization activities regarding this novel paradigm. Next, we present the key building blocks of an SDN infrastructure using a bottom-up, layered approach. We provide an in-depth analysis of the hardware infrastructure, southbound and northbound application programming interfaces (APIs), network virtualization layers, network operating systems (SDN controllers), network programming languages, and network applications. We also look at cross-layer problems such as debugging and troubleshooting. In an effort to anticipate the future evolution of this new paradigm, we discuss the main ongoing research efforts and challenges of SDN. In particular, we address the design of switches and control platforms—with a focus on aspects such as resiliency, scalability, performance, security, and dependability—as well as new opportunities for carrier transport networks and cloud providers. Last but not least, we analyze the position of SDN as a key enabler of a software-defined environment.

https://publications.uni.lu/bitstream/10993/20596/1/survey_on_SDN.pdf

Software-Defined Networking: A Comprehensive Survey

Software-Defined Networking (SDN) is an emerging paradigm that promises to change this state of affairs, by breaking vertical integration, separating the network's control logic from the underlying routers and switches, promoting (logical) centralization of network control, and introducing the ability to program the network. The separation of concerns introduced between the definition of network policies, their implementation in switching hardware, and the forwarding of traffic, is key to the desired flexibility: by breaking the network control problem into tractable pieces, SDN makes it easier to create and introduce new abstractions in networking, simplifying network management and facilitating network evolution. In this paper we present a comprehensive survey on SDN. We start by introducing the motivation for SDN, explain its main concepts and how it differs from traditional networking, its roots, and the standardization activities regarding this novel paradigm. Next, we present the key building blocks of an SDN infrastructure using a bottom-up, layered approach. We provide an in-depth analysis of the hardware infrastructure, southbound and northbound APIs, network virtualization layers, network operating systems (SDN controllers), network programming languages, and network applications. We also look at cross-layer problems such as debugging and troubleshooting. In an effort to anticipate the future evolution of this new paradigm, we discuss the main ongoing research efforts and challenges of SDN. In particular, we address the design of switches and control platforms -- with a focus on aspects such as resiliency, scalability, performance, security and dependability -- as well as new opportunities for carrier transport networks and cloud providers. Last but not least, we analyze the position of SDN as a key enabler of a software-defined environment.

is a network or group of networks under a common administration and with common routing policies. BGP is used to exchange routing information for the Internet and is the protocol used between Internet service providers (ISP). Customer networks, such as universities and corporations, usually employ an Interior Gateway Protocol (IGP) such as RIP or OSPF for the exchange of routing information within their networks. Customers connect to ISPs, and ISPs use BGP to exchange customer and ISP routes. When BGP is used between autonomous systems (AS), the protocol is referred to as External BGP (EBGP). If a service provider is using BGP to exchange routes within an AS, then the protocol is referred to as Interior BGP (IBGP).

Border Gateway Protocol

Software defined network (SDN) is one of the most interesting research topic that is currently being investigated. The inclusion of artificial intelligence (AI) can improve the performance of routing protocols. Nowadays the application of AI over routing protocols is only applied to real devices, especially in wireless sensor nodes. In this paper, we present a new proposal to implement an intelligent routing protocol in a SDN topology. The intelligent routing protocol is based on the reinforcement learning process that allows choosing the best data transmission paths according to the best criteria and based on the network status.

Including artificial intelligence in a routing protocol using Software Defined Networks

Software Defined networks (SDNs) paradigm tries to improve the network performance, facilitating the network management and the scalability basing on open-source software and adding a new entity called controller that manages the entire network. One of the goals of the controller is taking decisions in regards to routing instead of distributing it among the network nodes, as usual. However, this field inside SDN needs more work because it is not clearly defined how the traditional routing protocols will work over a SDN. Thus, in this paper, we analyze how a dynamic routing protocol as Open Shortest Path First (OSPF) works in a SDN. The study analyzes the stability of network through parameters as convergence time and round trip time (RTT) and the quality of service (QoS) when a video is streamed between end devices. The results have been compared with a traditional network in order to evaluate the similarity in terms of stability and performance. Results show that, despite the proposal uses an OSPF implementation that does not have a performance as good as the traditional solution in terms of convergence time, with the SDN proposed we get better performance in terms of Quality of Service.

OSPF routing protocol performance in Software Defined Networks

Off-the-shelf routing products are often constrained by being designed to meet specific needs, in terms of both software and hardware. Networking professionals may face problems that require customization of software, or additional processing facilities or data storage, which are not provided for by those products. The Quagga Routing Suite provides implementations of several common routing protocols, distributed over multiple processes communicating via IPC, and support for their development, with source code provided under a modification-friendly license. Quagga can help networking professionals build such custom solutions, in combination with other open source software packages. Quagga also provides a path for network researchers to increase the visibility of their work, making it available to a wider community for potential testing and use, increasing the impact of that research.

David Lamparter

Papers

Introduction to the quagga routing suite