| 摘要 |
An active loop-free topology established by a Rapid Spanning Tree Algorithm and Protocol (RSTP) emanates from an original root bridge. Upon a bridge directly connected to the root bridge suspecting a failure in the root bridge, the bridge directly connected to the root bridge generates a Root Failure Suspicion Notification (RFSN) Bridge Protocol Data Unit (BPDU) comprising a standard Rapid Spanning Tree (RSTP) BPDU portion and a compressed failed root identifier portion uniquely identifying the root bridge which is suspected of failing. The RFSN BPDU is propagated amongst the bridges in the network. The bridges which can identify a flag in the standard RSTP BPDU portion of the RFSN BPDU decompress the compressed failed root identifier and compare it to the stored root identifier at each bridge. If the received failed root identifier in the RFSN BPDU corresponds to the stored root identifier of the bridge, the bridge deletes the stored root identifier. The bridge then commences a time out during which, if further RFSN BPDUs are received, only the BPDU portion is acted on and the failed root identifier portion is ignored. The RSTP BPDU portion is acted on in the standard way pursuant to the RSTP protocol whether or not the bridge can also identify the flag or the compressed failed root identifier in the RFSN BPDU. Conversion to a new active topology is facilitated by deleting the original root bridge identifier which is suspected of failure from the memory of the bridges. |
