STP Bridge ID is 8 bytes in length. First two bytes are the STP Bridge Priority of the local bridge/switch you're looking at, which ranges from 0 to 65535 (default is 32768). The remaining 6 bytes are a MAC address assigned to that bridge/switch.
When STP Root Bridge election takes place, bridges/switches exchange Bridge IDs with each other. The one advertising the lowest value (highest priority) Bridge Priority wins the election. In the case of a tie on Bridge Priority, the MAC address is used to break the tie; again, the one with the lowest value wins.
STP Root ID is the Bridge ID of the current bridge/switch that is acting as the Root Bridge for a particular Spanning Tree.
When Root ID and Bridge ID are the same on a local bridge/switch, you're looking at the Root Bridge itself.
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 custome...