[c-nsp] Spanning-Tree question

[Tom Sands]

Though you using 2 different VTP domains/VLAN databases, are the VLANs 
per business unit at least unique so the VLAN databases don't have 
overlapping VLANs?

What's the purpose of interconnecting the 4 switches?

What are the connections between the 4 switches? access port (same vlan 
on each side or every switch)? trunk? L3?




------------------------------------------------------
Tom Sands			  				
Chief Network Engineer				
Rackspace 	    	
(210)312-4391	   	
------------------------------------------------------

Aaron R wrote:
> Hi Guys, 
> 
>  
> 
> Ive got a problem that I am hoping someone can have a look at. I currently
> have four 3750's. Two belonging to one business unit and two belonging to
> another. Each group of switches is running a separate VTP domain / VLAN
> database.
> 
> I am running PVST however when I connect the final link between the four
> switches there is a loop and spanning tree doesn't block any of the ports.
> Would anyone have any clue as to why this would be happening? Could it have
> something to do with the link between the Business units being on separate
> VLANs? We don't want the possibility of VLAN corruption occurring hence the
> different VTP domains. Currently I am shutting down one of the uplink ports
> to Business A to remedy this problem. Please see the diagram below. 
> 
>  
> 
> Cheers,
> 
>  
> 
> ------------------------                         ------------------------
> 
> | 3750 Switch 1  |------- Trunk ------ | 3750 Switch 2  |
> 
> |  Business A     |                        |  Business A     |
> 
> -------------------------                        -------------------------
> 
>            |   VL 50                                   |   VL 50
> 
> 
>            |                                              |
> 
>            |   VL 100                                 |    VL 100
> 
> 
> ------------------------                         ------------------------
> 
> | 3750 Switch 3  |------- Trunk ------ | 3750 Switch 4  |
> 
> |  Business B     |                        |  Business B     |
> 
> -------------------------                        -------------------------
> 
>  
> 
>  
> 
> Aaron.
> 
>  
> 
>  
> 
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> 


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