Is there are switch where you accidently connected VLAN 150 to VLAN 1? For example, a VLAN 150 access port connected to the default VLAN of another switch. You may want to apply BDPU filters to certain ports to segment the network until you track down the issue. Any port with a BDPU filter will disable spanning tree between the interconnected switches on that port.
-Matt On Dec 9, 2008, at 10:12 PM, Travis Johnson wrote: > Ok. When I bring the ring back up, the switch we have running > spanning tree changes VLAN1 to "blocking" on one port, but the > VLAN150 still shows "forwarding"... and creates a loop on VLAN150. > Where do I start? I'm not sure what to even look for or how to > troubleshoot this? > > Travis > Microserv > > Matt Liotta wrote: >> >> Check and see if you are running PVST, which runs spanning tree on >> each VLAN. >> >> -Matt >> >> On Dec 9, 2008, at 7:30 PM, Travis Johnson wrote: >> >> >>> Ok... found the original problem... a few switches did not have the >>> vlan >>> setup in the vlan database. So the VLAN is up and working now... but >>> the >>> problem is because we have a "ring", we use Spanning Tree to keep >>> from >>> having a loop in the network. But when we bring up the VLAN, the >>> spanning-tree does not start blocking the VLAN traffic. It does >>> block >>> the "normal" VLAN1 traffic (like it always has), but the new VLAN >>> never >>> gets "blocked", so it creates a loop around the ring. >>> >>> Am I missing something? I've checked the settings and can't find >>> anything that I missed to make it work... >>> >>> Travis >>> Microserv >>> >>> Eric Rogers wrote: >>> >>>> Try a "show interface fastethernet x/y switchport" and see what is >>>> the >>>> status of the port and that trunking VLANs enabled are also >>>> trunking >>>> VLANs active. >>>> >>>> >>>> >>>> Eric >>>> >>>> >>>> >>>> From: [EMAIL PROTECTED] [mailto:wireless- >>>> [EMAIL PROTECTED] On >>>> Behalf Of Travis Johnson >>>> Sent: Tuesday, December 09, 2008 5:17 PM >>>> To: WISPA General List >>>> Subject: Re: [WISPA] Cisco VLAN help >>>> >>>> >>>> >>>> Hi, >>>> >>>> By default, when doing the switchport mode trunk, all VLAN's are >>>> allowed >>>> (I even issued the command "switchport trunk allowed vlan all" >>>> and it >>>> did not display on the sho conf afterward). >>>> >>>> Travis >>>> Microserv >>>> >>>> Patrick Shoemaker wrote: >>>> >>>> Travis Johnson wrote: >>>> >>>> >>>> Hi, >>>> >>>> I need some Cisco switch VLAN help. >>>> >>>> I currently have about 60 Cisco 3500 series switches connected >>>> via the >>>> GBIC ports all in a ring configuration with spanning tree. I am >>>> trying >>>> to setup a VLAN for a customer between two of the FastEthernet >>>> ports so >>>> they can connect their offices. I have port 5 on each switch >>>> setup in >>>> VLAN105 and every GBIC port on all the switches setup as >>>> trunking ports. >>>> There are 17 other cisco switches between these two. >>>> >>>> I have this setup between two other offices, but they are >>>> directly >>>> connected to each other, with no other switches in between. >>>> >>>> What am I missing? >>>> >>>> Travis >>>> Microserv >>>> >>>> >>>> >>>> ------------------------------------------------------------------------ >>>> -------- >>>> WISPA Wants You! Join today! >>>> http://signup.wispa.org/ >>>> >>>> ------------------------------------------------------------------------ >>>> -------- >>>> >>>> WISPA Wireless List: wireless@wispa.org >>>> >>>> Subscribe/Unsubscribe: >>>> http://lists.wispa.org/mailman/listinfo/wireless >>>> >>>> Archives: http://lists.wispa.org/pipermail/wireless/ >>>> >>>> >>>> >>>> Is each trunk port in the path set to forward the VLAN with >>>> command: >>>> >>>> switchport trunk allowed vlan xxx >>>> >>>> A sh int for an example trunk and access port would be handy. >>>> >>>> >>>> >>>> >>>> -------------------------------------------------------------------------------- >>>> WISPA Wants You! 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