Hybrid Software Defined Networking Network Research Articles

Multi-Objective Control Plane Dimensioning in Hybrid SDN/Legacy Networks

Software defined networking (SDN) is gaining the confidence of network operators, who are increasingly motivated to introduce it in their networks. However, since SDN is based on centralized control plane (decoupled from the data plane), it is incompatible with distributed control plane of legacy networks. As adopting SDN by complete overhaul of existing legacy networks is infeasible, several solutions propose to incrementally adopt SDN in legacy networks, resulting in hybrid SDN/legacy networks during the transition phase. While strategies to effectively introduce SDN switches in legacy networks have received significant attention in the literature, the same is not true for the associated SDN controller placement in hybrid SDN networks. In this paper, we introduce and formulate the multi-objective control plane dimensioning problem in hybrid SDN/legacy networks, considering network resilience, flow-setup latency and controller load balancing as objectives. We propose optimization models for both the single-objective as well as the multi-objective controller placements. We model both controller processing latency (based on queueing theory) and inter-controller network state synchronization latency (based on Steiner trees) without compromising linearity of the optimization formulations. A genetic algorithm-based heuristic is presented to efficiently deduce the approximate Pareto frontier for our problem. Extensive simulations over a large number of real networks establish the effectiveness of our approach in terms of several single-objective and multi-objective performance metrics.

A hybrid SDN solution for mobile networks

The adoption of Software Defined Networking (SDN) has encountered resistance mainly due to its disruptive nature for current deployed networks. In order to allow a smoother transition of SDN into production networks and take advantage of SDN’s characteristics, a mix of SDN with traditional networks, or Hybrid SDN Networks, can be deployed, paving the path to fully SDN-capable networks. The introduction of SDN allows for new and more efficient network optimization methods. This paper presents a Hybrid SDN Mobile Core Network for 4G and Non-Standalone 5G, which integrates support for Wi-Fi access, traffic offloading capabilities from 3GPP to non-3GPP Access and dynamic non-3GPP network slice instantiation, while still being flexible enough to be used in Standalone 5G. Results showed that the virtualization of the Mobile Core Network and the introduction of SDN in its architecture (making it a hybrid SDN solution) presented no significant impact in latency, attachment time and throughput in the mobile network when compared with a traditional deployment, coupling it with all the flexibility that SDN provides. Furthermore, benefits of traffic offloading for both the end user and the network operator are also shown.

Soft-Mesh: A Robust Routing Architecture for Hybrid SDN and Wireless Mesh Networks

Wireless Mesh Networks (WMNs) are considered self-organizing, self-healing, and self-configuring networks. Despite these exciting features, WMNs face several routing challenges including scalability, reliability and link failures, mobility, flexibility, and other network management issues. To address these challenges, WMNs need to make programmable to allow modifications of standard techniques to be configured and implemented through software programs that can be resolved by integrating Software Defined Networking (SDN) architecture. SDN, being a cutting-edge technology promises the facilitation of network management as well as routing issues of wireless mesh networks. However, the evolution of the legacy IP-based network model in its entirety leads to technical, operational, and economic problems that can be mitigated by full interoperability between SDN and existing IP devices. This study introduces a Robust Routing Architecture for Hybrid Software-Defined and Wireless Mesh Networks (Soft-Mesh), by systematic and gradual transitioning of WMNs to SDNs in an efficient manner. The main objective of this paper is to suggest improvements to the architecture of the SDN node that allow the implementation of various network functions such as routing, load balancing, network control, and traffic engineering for the hybrid SDN and IP networks. Mininet-WiFi Simulator is used to perform various experiments to evaluate the performance of proposed architecture by creating a hybrid network topology with a varying number of nodes that is 50, 100, 150, 200, and 250 including SDN hybrid and legacy nodes with varying proportion of SDN hybrid and legacy nodes. Results are taken for the average UDP throughput, end-to-end delay, packet drop ratio, and routing overhead while comparing with traditional routing protocols including Optimized Link State Routing (OLSR) and Better Approach to Mobile Adhoc Networking (BATMAN) and with existing hybrid SDN/IP routing architectures including Hakiri and wmSDN. The analysis of simulation results shows that the proposed architecture Soft-Mesh outperforms in terms of the aforementioned performance metrics than the traditional and exiting hybrid routing protocols. Soft-Mesh gives 50% to 70% improved results concerning the incremental proportion of SDN hybrid nodes.

ProgLIMI: Programmable LInk Metric Identification in Software-Defined Networks

In this paper, we propose the Programmable LInk Metric Identification (ProgLIMI) infrastructure for software-defined networking (SDN) networks. ProgLIMI identifies round-trip link metrics (RTLMs) from accumulated end-to-end metrics of selected measurement paths by leveraging the flexible routing control capability of SDN networks. ProgLIMI mainly solves three sub-problems: 1) monitor placement; 2) linearly independent measurement path construction; and 3) flow rule design. To reduce measurement cost, ProgLIMI tries to minimize the number of required monitors and flow rules. In this paper, we address the three sub-problems for both full and hybrid SDN networks. For full SDN networks, ProgLIMI can achieve full RTLM identification using only one monitor and two flow rules in each SDN switch. In contrast, the RTLM identification in hybrid SDN networks is more complicated due to the routing constraint of hybrid SDN networks. We first prove that the monitor placement problem in hybrid SDN networks is NP-hard. We then formulate the monitor placement and measurement path selection problem in hybrid SDN networks and propose a greedy heuristic algorithm to solve the problem efficiently. Our evaluations on both physical testbed and simulation platform reveal that ProgLIMI can accurately identify the RTLMs (delay and loss rate). Besides, ProgLIMI is also resource efficient, i.e., it only requires two flow rules in each SDN switch and a small number of monitors, and the extra probing traffic load incurred by ProgLIMI is also low.

Hybrid SDN Networks: A Survey of Existing Approaches

Software defined networking (SDN) decouples the control plane from the data plane of forwarding devices. This separation provides several benefits, including the simplification of network management and control. However, due to a variety of reasons, such as budget constraints and fear of downtime, many organizations are reluctant to fully deploy SDN. Partially deploying SDN through the placement of a limited number of SDN devices among legacy (traditional) network devices, forms a so-called hybrid SDN network. While hybrid SDN networks provide many of the benefits of SDN and have a wide range of applications, they also pose several challenges. These challenges have recently been addressed in a growing body of literature on hybrid SDN network structures and protocols. This paper presents a comprehensive up-to-date survey of the research and development in the field of hybrid SDN networks. We have organized the survey into five main categories, namely hybrid SDN network deployment strategies, controllers for hybrid SDN networks, protocols for hybrid SDN network management, traffic engineering mechanisms for hybrid SDN networks, as well as testing, verification, and security mechanisms for hybrid SDN networks. We thoroughly survey the existing hybrid SDN network studies according to this taxonomy and identify gaps and limitations in the existing body of research. Based on the outcomes of the existing research studies as well as the identified gaps and limitations, we derive guidelines for future research on hybrid SDN networks.

Intelligent path control for energy-saving in hybrid SDN networks

As power consumption of the internet has been growing quickly in recent years, saving energy has become an important problem of networking research. Software-Defined Networking (SDN) brings excellent opportunities to improve network performance and reduce energy consumption by flexible centralized control. However, due to budget constraints and technique limitations, ISPs can upgrade only a limited number of conventional switches in backbone networks to SDN devices at one time. In this paper, we propose one heuristic scheme for incrementally deploy SDN switches in hybrid SDNs, the objective of which is to achieve energy saving by rerouting the flows to shut down idle links and switches as many as possible. Our solution can achieve two objectives: 1) maximizing the network control ability with a given SDN switches upgrading budget constraint, and 2) maximizing energy saving by shutting down idle links and switches with deployed SDN switches. The results of evaluations show that our scheme can achieve 95% of the number of flows controlled with only 10% of upgrading cost, and it also can achieve saving more about 10% of the total power consumption when compared to the existing solutions.

Traffic engineering in hybrid SDN networks with multiple traffic matrices

Traffic engineering (TE) is an efficient tool for optimizing traffic routing and balancing the flows in networks. Traffic is dynamic, previous TE optimization over a single traffic matrix (TM) have some limitations, because a single TM can have big measurement errors and is insufficient to depict the traffic flucuations. Thus, we consider using multiple TMs to overcome these limitations. With the emergence of Software Defined Networking (SDN), we can route flows more flexibly and better balance the flows over multiple TMs. However, due to the difficulties of full SDN deployment, hybrid SDN networks will be the prevailing architectures in the near future. Therefore, optimizing the routing over multiple TMs in a hybrid SDN network is of great interest.In this paper, we first formulate the problem of TE over multiple TMs and prove its NP-hardness. Next, we propose a heuristic algorithm for optimizing routing over multiple TMs by combining offline weight setting optimization with online splitting ratio optimization. Furthermore, we prove that the routes obtained in our algorithm are loop-free, and we provide an upper and lower bound of our proposed algorithm. Finally, we evaluate our method on measured traffic datasets with three network topologies. The results of extensive experiments demonstrate that the maximum link utilization of a network can be optimized better using our proposed algorithm.