In 2001, the IEEE introduced Rapid Spanning Tree Protocol (RSTP) as 802.1w. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. RSTP was designed to be backwards-compatible with standard STP.
While STP can take 30 to 50 seconds to respond to a topology change, RSTP is typically able to respond to changes within 3 × Hello times (default: 3 times 2 seconds) or within a few milliseconds of a physical link failure. The so-called Hello time is an important and configurable time interval that is used by RSTP for several purposes; its default value is 2 seconds.Standard IEEE 802.1D-2004 now incorporates RSTP and obsoletes the original STP standard.
I can tell you from a real world network - I have seen a blocked port transition to forwarding in under 10 msec.
Just some remarks: if both ends of a link are RSTP and use the proposal-agreement phase, they can converge very rapidly, i am talking maximum 2-3 seconds. I have once seen a situation where it took up to 6 seconds to converge to backup links. Upon troubleshooting, this was caused by the fact that the remote side did not talk STP at all (or no RSTP in every case). If the remote-end does not reply to a "proposal" packet, it will take 6 seconds before this "proposal" attempt times out and normal non-proposal convergence kicks in...
I have not done some big installtions but RSPT has converged very rapidly in some of the tests that I have done for customers. It all depends on how big your topology is and what kind of traffic you have on the network. In some of the tests that I have done with Cat6K, Cat4500 and Cat3750 with RPVST enabled and voice/video/wireless traffic on the switches, it converged rapidly without voice/video calls getting dropped, wireless users getting reassociated in link failure scenarios. We did some of the parameters tuning in some cases but even with the default timers, it was a rapid convergence.
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
Introduction Featured Speakers Luis Espejel is the Telecommunications
Manager of IENova, an Oil & Gas company. Currently he works with Cisco
IOS® and Cisco IOS XE platforms, and NX to some extent. He has also
worked as a Senior Engineer with the Routing P...
In this session you can learn more about Layer 3 multicast and the best
practices to identify possible threats and take security measures. It
provides an overview of basic multicast, the best security practices for
use of this technology, and recommendati...