MS225-48LP Redundant Uplinks to MX250 Firewall

[GFrazier]

I recently setup network hardware for a client site. I connected the core firewall to the MX with redundant uplinks, however, at some point I lost all connectivity to the switches.  The setup is 3 stacked MS225 switches uplinked via fiber to the MX:  Switch 1 uplinks from port 49 to MX port 25, Switch 3 uplinks from port 49 to MX port 26. 

I am on firmware version 14.8 on the switches - I have read up on the firmware issues and there is nothing stating issues with STP and BPDU.  Also, in my switch settings, I had not yet set a STP priority since we have not connected any other switches yet aside from the core stack.  I only had the option of selecting the entire stack, not an individual switch.

After working with no issues for weeks, the connection to the switches were lost due to the redundant uplink a Meraki Support Rep had discovered, but was unable to tell me if this was a known issue.   I did inquire if it had anything to do with me using port 49 on both switches in the same stack, but they were unable to answer that.  

I am now very concerned and afraid to try redundant uplinks with this particular hardware... This client site is in a different state and I want to ensure redundancy as much as possible.  I will be installing the rest of the switches on the other floors in about 2 weeks and need to know if there is any pointers someone can give that will ensure the redundant uplinks will work without going through the same problem once the client officially opens.

[cmr]

@GFrazier Are the MS225s routing or is the MX250 routing?  I had loads of problems with an MS225 stack in L3 mode that has redundantly connected MX100s.

The issues have all been fixed since I upgraded to 14.12. 

The MXs are running 15.42

I have a random selection of ports as the uplinks so cannot answer on that specific point, if you suspect something like that could you move one to port 50-52?

[GFrazier]

@cmr 

Hi, I think its more the MS225's because from what I understand, the MX's do not do Spanning Tree - they don't recognize BPDU packets, correct? 

An individual switch cannot be selected as a root when the switches are stacked, so I was thinking since the stack is seen as one switch, it would simply see the 49th port on switch 3 as port 147.  Or at lease differentiate switch 1 port49, switch 2 port49 and switch 3 port49.

Not sure how it sees it, but if the Firewall is not a factor in selecting the STP root, and the entire stack is the only STP root that can be chosen, then maybe using both ports 49 as an uplink may have been the issue.  I can try using a different port for the redundant uplink - I will do that and see what happens. 

I don't have the MS225s in L3 mode at the moment because I didn't want to overly complicate the configurations being that we just moved all of their servers to Azure.

[cmr]

@GFrazier I'd definitely update to 14.12 as the issue I had was individual switches in the stack rebooting and sometimes one would then send another down leaving the stack inaccessible for up to an hour.  However it did route data fine for all but the 2 minute reboot as the management path was through one MX and the data paths through another pair of MXs.

[GFrazier]

@cmr   Oh ok, so I did have a couple of times where the switches did lose connectivity as if they were rebooted - I had no idea why.  So, this is a known issue with the MS225's?? I read the "Known Issues" with the 14.8 and it only spoke of the MS350 with such issues.  Do you work with the MS225's?  I was trying to stay away from the Beta versions, but looks like I may have to give it a try.  

[Bruce]

@GFrazier all the MS14 versions are Beta, so you're already on beta code with 14.8. The Stable Release for the MS line is the 12 firmware. In the Meraki world the latest Beta firmware is fully supported by the Meraki Support team so I wouldn't worry too much about it being Beta - although occasionally you may hit the odd bug.

[cmr · Accepted solution]

@GFrazier I reported a bug with an MS210 stack, but was told that it impacted both MS210s and MS225s when stacked, it was mentioned as resolved in the 14.12 release notes and the case was updated to tell me that this release fixed the issue I was seeing: https://community.meraki.com/t5/Switching/New-MS-14-12-firmware-unexplained-reboot-and-L3-issue-upon...