|
As an innovative network paradigm, Software Defined-Networking (SDN) has drastically changed the network control and management of complex enterprise networks by making them more flexible and easier to be executed. The main function of SDN is to separate the control and management planes from the data plane by introducing specific protocols (such as OpenFlow) to operate between these layers. Although SDN leads to several benefits over traditional (legacy) network, it has not been adopted yet by majority of organizations due to several reasons, e.g., heavy budget burdens for its establishment, fear of down time as the technology has not attained maturity level, effectiveness of legacy routing for in-band connectivity among SDN controller and forwarding devices, etc. Instead, a gradual transition towards SDN can be observed in which both types of technologies (i.e., SDN and traditional networking) co-exist. In this paradigm, a limited number of SDN-enabled devices is initially deployed among traditional (legacy) network devices. This coupling of both technologies is best known as “hybrid SDN” (HSDN). Moreover, hybrid SDN switches (i.e., with both SDN and legacy networking functionality) are also available to form a hybrid SDN architecture. These partial deployments of SDN technologies among the traditional devices pose several challenges and issues that need to be addressed by the research community for smooth and successful operations of hybrid SDN. The aim of this special issue is to collect the state of arts and solutions related to the partial deployment of SDN in a traditional network. |
