Sorry for being so vague, it was first thing in the morning, just getting my first cup of coffee and rubbing the sleep out of my eyes. (Yes, I need a life if I wake up thinking about these questions.)
This is a 6513. That is what I thought. The BID is the MAC address on the card, hence why I am curious as to how this has come about. :) Here is the header output of the show spantree command, the second 6513 shows spanning tree as disabled: VLAN 1 Spanning tree mode PVST+ Spanning tree type ieee Spanning tree enabled Designated Root 00-00-00-00-00-00 Designated Root Priority 0 Designated Root Cost 0 Designated Root Port 1/0 Root Max Age 0 sec Hello Time 0 sec Forward Delay 0 sec Bridge ID MAC ADDR 00-00-00-00-00-00 Bridge ID Priority 32769 (bridge priority: 32768, sys ID ext: 1) Bridge Max Age 20 sec Hello Time 2 sec Forward Delay 15 sec All the ports show as VLAN1. ---------------------------------- As my curiosity grew I checked "Per-VLAN". Our closests are configured to look at one of the core switches as the root bridge, the other core as the secondary root bridge. I went to one of the closets and received the same output as above for "show spantree". But if I issue "show spantree I receive the information that shows me which device it uses as the root bridge. Would it be safe to say then that due to PVST+ the MAC address comes out as all zero's when you issue "show spantree" without a VLAN designation? Kim > > From: "Priscilla Oppenheimer" > Date: 2002/07/11 Thu PM 03:20:41 EDT > To: [EMAIL PROTECTED] > Subject: RE: All 0's MAC Root Bridge [7:48578] > > 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=48626&t=48578 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
