Kim Graham wrote: > > The other day I was delving a bit into spanning tree and I came > across something that puzzled me. > > Searching out which device was the root bridge I found the MAC > address (BID) on the root bridge to be all zero's. (show > spantree snippets). > > Spanning tree mode PVST+ > Spanning tree type ieee > Designated Root 00-00-00-00-00-00 > Bridge ID MAC ADDR 00-00-00-00-00-00 > > Without finishing chapter 7 (Spanning Tree) in my LAN switching > book I am puzzled as to whether this is a preset MAC address or > self assigned.
The Bridge ID MAC address is preassigned to the switch by the manufacturer. The address would be one of the many assigned to the supervisor or backplane in Cisco's case, depending on the switch model. Which model are you using? Seeing all zeroes is extremely strange, as you know, since you're asking this question! ;-) A few things I'm wondering about: What state was the spanning tree in? Was it still converging? Did the outpu continue to say this weirness, or did it change after a while? For which VLAN were you displaying this information? I notice that you're doing Per-VLAN Spanning Tree. Could this info be for a VLAN that doesn't actually exist or for a VLAN where spanning tree is disabled? Can you send us your config? I guess the bottom line is that we need more info from you. Priscilla > > Any thoughts? Why or how did this occur? > > Kim > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=48616&t=48578 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]