IEEE 802.1w is a Rapid Spanning Tree Protocol (RSTP) that can be seen as an evolution of the 802.1 standard. In most cases, RSTP performs better than Cisco Systems' proprietary extensions without any additional configuration. 802.1w is also capable of reverting back to IEEE 802.1D in order to interoperate with legacy bridges (thus dropping the benefits it introduces) on a per-port basis.
The motivations behind the development of this supplement include:
The desirability of developing an improved mode of Bridge operation that, while retaining the plug-and-play benefits of Spanning Tree, discard some of the less desirable aspects of the existing Spanning Tree protocol, in particular the significant time taken for it to re-configure and restore service on link failure/restoration;
The realisation that, while small improvements in Spanning Tree performance are possible through manipulation of the existing default parameter values, it is necessary to introduce significant changes to the way the Spanning Tree algorithm operates in order to achieve major improvements; The realisation that is possible to develop improvements to the operation of Spanning Tree that take advantage of the increasing prevalence of structured wiring approaches, while still retaining compatibility with equipment based on the original Spanning Tree algorithm.
Reference:
http://en.wikipedia.org/wiki/802.1w
