GldenJoe - You are spot on.  The problem was BPDU Filtering.  The 5700 switches do not have port level control of BPDU guard / filtering via the Device Manager interface.  IT has to be enabled / disabled for the entire switch.  Although I suspect the CLI interface would allow port level enable / disable functionality.  Anyway, Those options were disabled on the Meraki side at the port level but they were left enabled on the 5700.  Which was forcing "err-disable until your err-disable recovery kicks in and re-enables the ports and the cycle continues after receiving new BPDU's" .  Your last comment set: "please take care in using lacp where possible and be very careful around static port-channels."  What issues should I watch for with regard to LACP (active)?  I completely understand the second half of that comment because I have witnessed first hand the packet loss associated with static port-channels when a link falls out then comes back up.  Thank you for taking the time to respond.   ... View more

The topology is 2 sections of OT network VLAN3 / 192.168.3.x and VLAN 4 / 192.168.4.x are tied together via a fiber connection between 2 Meraki MS125 switches.  The OT networks have several Stratix 5700 switches each (12) on VLAN 3 and (7) on VLAN 4.  The OT Servers hang off the Meraki switches VLAN 3 has 2 severs on VLAN 3 Meraki ports and VLAN 4 has 1 server on VLAN 4 Meraki port.  There is also a router / firewall on the VLAN 3 Meraki that routes between VLANs and other things.  Anyway, all the 5700 switches use MSTP and the Meraki's use RSTP but everything is fine.  EtherChannel between 5700s is straight forward and very easy to do, although you have to use CLI to enable / disable individual ports in an EtherChannel, Once the EtherChannel is configured the device manager web based config tool for 5700s wont allow you to effect the individual ports of an EtherChannel, only the full channel can have setting changes.  Anyway, Everything works well as is but there is a single point of failure on VLAN3 where a single cable controls the connectivity of all OT devices on VLAN 3 to the servers.  I was hoping to add redundancy to the system by creating an EtherChannel between the 5700 that ties the entire VLAN 3 OT network to the servers hanging off the VLAN 3 Meraki.  Each time I try to configure the channel just bounces up and down.  It will stay up for about 3 - 4 minutes then all links will drop out for about 30 seconds then come back up.  When connectivity is lost the Channel disappears from the MSTP table.  It doesn't say BLK or ALT it goes away completely.  I have tried lowering the STP priority on the 5700 to force it to Master.  It works it becomes master but the same thing happens it falls out for 30 seconds every 3-4 minutes.  Then I tried disabling RSTP on the trunk ports of the Meraki ( lost all connectivity) Error messages are always the same in syslog: %PM-4-ERR_DISABLE: Channel-misconfig (STP) error detected on Po1, putting Po1 in err-disable state.  I wouldn't normally be so free with config changes on my network but I am in shutdown so production doesn't need access to servers till 7/13.  Any advice would be great.  I'm an just about out of ideas.   ... View more