A comprehensive study of different objectives and solutions of controller placement problem in software‐defined networks

Abstract

Software-defined network (SDN) is a programmable networking paradigm that enables logically centralized network management. In order to overcome the shortcomings of traditional networks, SDN has come into the picture. SDN is a recent and fast-forwarding technique that involves separating the network's control plane from the data plane. This network also allows us to directly communicate with the applications through application programming interfaces. A network administrator can directly modify and update the routing policies and rules in SDN. Apart from the advantages given by the SDN, it has also been found that separation of control plane directly affects the network performance.Finding the optimum number of controllers and their locations to improve the performance is one of the fundamental research problems in SDN which is also commonly known as the controller placement problem (CPP). In this article, we have addressed the CPP in SDN in detail and investigated the optimization objectives that influence CPP. The state-of-the-art of this article is to review almost all the optimization objective along with their mathematical formulation and survey the CPP solutions proposed by the other researchers'. Classified the CPP into three parts based on the objectives and solutions of CPP and reviewed the impact of these objectives on network performance. This article gives a comprehensive overview of current strategies on CPP in SDN and at last, we give some research issues that can be further explored by the researchers.

Controller placement problem during SDN deployment in the ISP/Telco networks: A survey

“…Many studies on the SDN have already been done. 28,[36][37][38]51 But none of them have particularly addressed ISP/Telco networks. Therefore, research must be confined to CPP issues in large-scale ISP/Telco networks.…”

“…In order to increase the WANs' scalability and stability, multi‐controller deployment is becoming popular 50 . Dhar et al 51 pay emphasis to the CPP issues with SDN and find that multiple controllers must be deployed in order to keep a large‐sized SDN scalable and reliable.…”

A cost‐effective and load‐balanced controller placement method in software‐defined networks

“…There have two types of packet flow rates: uniform and non-uniform. 48 Uniform packet arrival rate means loads of the switches are equal. If loads of switches are not the same then we call it non-uniform packet arrival rate.…”

“…In our method, the number of sub‐networks is equal to the number of controllers as we place one controller in each cluster, and the packet arrival rate is uniform to all the switches. There have two types of packet flow rates: uniform and non‐uniform 48 . Uniform packet arrival rate means loads of the switches are equal.…”

A robust‐link controller placement model for large‐scale software defined networks

“…As SDN networks continue to grow in size, multiple controllers are needed to transmit control information to multiple switches, thus collaborating to manage a large SDN network. 6,7 Therefore, in large SDN networks, how to determine the location of the controller and the mapping relationship between the controller and the switch are two key issues. Heller et al named it as controller placement problem (CPP).…”