CCNA Data Center DCICN 640-911 Official Cert Guide

RSTP States and Processes

The depth of the example does not point out all details of RSTP, of course; however, the example does show enough details to discuss RSTP states and internal processes.

Both STP and RSTP use port states, but with some differences. First, RSTP keeps both the learning and forwarding states as compared with STP, for the same purposes. However, RSTP does not even define a listening state, finding it unnecessary. Finally, RSTP renames the blocking state to the discarding state, and redefines its use slightly.

RSTP uses the discarding state for what 802.1D defines as two states: disabled state and blocking state. Blocking should be somewhat obvious by now: the interface can work physically, but STP/RSTP chooses to not forward ...