Principal switch selection
Every Brocade VCS Fabric-enabled switch, upon boot-up and after the Fabric port formation, declares itself to be a principal switch and advertises this intent on all fabric ports. The intent includes a priority and its switch WWN. If all switches boot up at the same time, the default priority is the same and all switches will compare their mutual intents. The switch with the lowest Switch WWN becomes the principal switch. The WWN is an industry-standard burnt-in switch identifier, similar to the Bridge-MAC except it is 8 bytes. The role of the principal switch is to decide whether a new RBridge joining the fabric conflicts with any of the RBridge IDs already present in the fabric. At the end of the principal switch selection process, all the switches in the cluster have formed a tree with the principal switch at the root.