Hi Michael, I can't tell from the configuration why the network slows down when switch A and B are directly connected. What I do noted is that the core switch is the root switch of vlan1, hence the spanning-t priority command. In case the bridge-id of one of the access switches is lower that switch will become the root of the spanning tree for other VLANs i.e. VLAN 10. Find out what switch is currently the root of the spanning tree per VLAN by issuing the show spanning-tree vlan x command. Where x is the VLAN number. Make the core switch the root of the spanning tree by isuing the spanning-tree vlan 1,100,x,y,z root primary command. In case you experience network degradation, likely caused by a loop, issue the command show spanning-tree vlan x detail to see the source of TCN BPDUs. HTH --Leon * Please rate ALL posts.
... View more
