Re: Brocade DS-6505-B Merging
This means that you are not using Brocade Virtual Fabrics (not all Brocade switches support the feature).
Also, you are not using Switch Connection Control, SCC, which can be used to restrict switches from joining the fabric.
Yes, you will need to set a unique domain ID and as a best practice set the insistent domain ID flag. If the merge is unsuccessful then the E ports will be 'isolated', and there will be an isolation reason, which would then help you to troubleshoot.