Okay, so after going through the information that RWelch linked, and some of the crosslinked information that it lead to I have come to the following.   We have only a Core Layer (this is layer 3 with all the vlans) and a Access layer, we don't have any need of a distribution layer because of density in the buildings.  Every IDF has a direct Single Mode (6 strand) fiber from the pair of Core MS425-32's.   For Priority.  I hear you about moving the Core to 4096, and access to 16,384 so that new switches will always be lower (higher numerically) than everything else.  I will do this but it won't change how it's operating, it just makes future changes easier.     In reading what they were talking about with Loop Guard, I have always kept that on because of this line by Cisco: "It is recommended that Loop Guard be enabled on non-designated fiber ports in physically redundant topologies. It is also recommended that Loop Guard be paired with Unidirectional Link Detection (UDLD). " Well,.. With LACP there really aren't any ports that are "Non-Designated", and as I read deeper into what Loop Guard is, I think I misunderstood it at first, as well as it's something that as you mentioned seems to have some issues.  I have a new plan here.  I will turn on Root Guard at all the core ports (this should change nothing since it should always be root, but gives some protection) and I will disable Guard at the access layer, but leave RSTP on of course.     After this I will turn LACP back on for the building I'm in, and test for a week.  If we have success I can roll it out campus wide. Thank you! James ... View more