Introduction

Traditionally, Data Centers used lots of Layer 2 links that spanned entire racks, rows, cages, floors, for as far as the eye could see. These large L2 domains were not ideal for a data center, due to the slow convergence, unnecessary broadcasts, and difficulty in administering. To optimize the data center network, we needed to reduce the use of and reliance on layer 2 protocols such as Spanning Tree. The challenge, however, is the fact that Data Centers need Layer 2 stretching from rack to rack, row to row, sometimes from data center to data center, not only for application requirements but also for fault tolerance and workload mobility. Numerous technologies have come forth to battle this limitation, such as TRILL, FabricPath, and VXLAN. Of these three, it is Virtual Extensible LAN (VXLAN) that has seen rapid adoption in modern data centers. (more…)