Recently we implemented spanning tree and redundant links in our infrastructure. This has resulted in systems on the default VLAN having intermittent connectivity problems when I plug in the backup link.
This is configured between a Cisco 3750 and a couple HP 2900 series switches. The 3750 stack also provides intervlan routing.
A few legacy devices in our environment are still running on a subnet assigned to the default VLAN - mostly printers and a few old servers. These predate any internal subnetting or dedicated network personnel. I'm getting one way routing from the default subnet, accessing reaching only systems plugged into one switch or the other, etc.
Nothing shows up in the switch logs.
I'm thinking that the best solution would be to migrate these devices to a new VLAN. This is something I've been doing in conjunction with a subnet migration for some time - this range is also a bogon net - but I'd rather not need to reconfigure all the attached hardware.
Is there something easier I've overlooked?
These are the spanning tree related settings I'm using. As far as I can tell things are set correctly. The spanning tree does work properly for all the other VLANs listed, just not 1.
spanning-tree mode mst spanning-tree extend system-id spanning-tree mst configuration name mstp revision 1 instance 1 vlan 1, 40, 70, 100, 250 spanning-tree mst 1 priority 0 spanning-tree mst 0 priority 4096
spanning-tree spanning-tree config-name "mstp" spanning-tree config-revision 1 spanning-tree instance 1 vlan 1 40 70 100 250