On the Study of SDN for Emulating Virtual LANs

摘要

Management of Virtual LANs (VLANs) is a tedious, error-prone and time-consuming process that can increase the operational cost (OPEX). Software-defined networking (SDN) on the other hand is an emerging paradigm providing an agile and application-driven method of networking. SDN is believed to ease the management of large and complex networks and decrease the OPEX. Both VLANs and SDN provide Layer-2 isolation on top of which further network functions can be orchestrated. VLANs functionality is limited to Layer-2 while SDN can be utilized for an extended set of network functions. Despite the evolving nature of SDN compared to VLANs, network administrators are quite fascinated by its new features. The desire for migrating existing VLANs functions to SDN may be throttled by the lack of performance results and the undefined benefits versus challenges tradeoff. Is such function migration can fade out VLANs in favor of SDN? What might be the possible hurdles that can hinder SDN in completely replacing VLANs? This paper takes a step towards answering such questions. We implement and studied four VLANs functions with SDN. The experience of implementing and studying these functions from a network administrator perspective give the insights that although VLANs function implementation with SDN presents some benefits there however exist various challenges that make it difficult to foresee the readily oust of VLANs. The major challenges include the evolving nature of SDN, the better performance, and scalability of new VLANs standards for larger carrier networks and the existing investment in VLANs-based network infrastructure.