Users Guide

Table Of Contents
Spanning Tree Protocol 875
on ports that should have a path to the root. The port where the switch
received the inferior BPDU is excluded because it already failed; self-looped
and designated ports are eliminated as they do not have a path to the root.
Figure 21-5. IRC Flow
Upon receiving a negative RLQ response on a port, the port has lost
connection to the root and the switch ages-out its BPDU. If all other non-
designated ports received a negative answer, the switch has lost the root and
restarts the STP calculation.
If the response confirms the switch can still access the root bridge via a
particular port, it immediately ages-out the port on which the inferior BPDU
was received.
If the switch only received responses with a root different from the original
root, it has lost the root port and restarts the STP calculation immediately.