User manual
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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 incorporates RSTP and obsoletes the original STP standard Select RSTP function in
rapid ring network interface as follows:
（
Figure 6.6.17
）
Rapid Spanning Tree of concepts:
Switch priority
：
As the bridge priority
，
the bridge priority and bridge MAC address combine
bridge ID
，
the smallest ID bridge will become the root bridge on the network.
Polling interval
：
how often send BPDU packet at one time.