Port being disabled

Question

So, i have a Synology router, which has a mesh unit. Just recently, when i connect the mesh unit to the router via ethernet (the switch is also connected directly to the router), the switch is disabling the port connected to the router. I see this in the switch logs (ignore timestamps).

<13> Oct 5 21:45:29 NETGEAR-24-PORT-SWITCH-1 TRAPMGR[trapTask]: traputil.c(753) 1305 %% NOTE Link Down: g1

<14> Oct 5 21:45:29 NETGEAR-24-PORT-SWITCH-1 DOT1S[dot1s_timer_tas]: dot1s_control.c(1598) 1303 %% INFO Rate limit of 15 for 3 consecutive seconds has been exceeded on port g1

<12> Oct 5 21:45:29 NETGEAR-24-PORT-SWITCH-1 DOT1S[dot1s_timer_tas]: dot1s_ih.c(2010) 1302 %% WARN Diagnostically disabling interface g1 as rate limit of 15 for 3 consecutive seconds has been exceeded

So i guess my question to this community is what set of circumstances could cause this situation to happen? I'm not a mega expert on networking, so fee free to dumb down any answers!

Thanks in advance for any tips.

soundsessential · Answer

I did, after much back and forth with Synology support, which even went to the developers in Taiwan. Essentially the issue is plugging the MR2200 into the router when the switch is connected to it as well. It causes a loop burst when switching from the wireless backhaul to ethernet. Bear in mind this could be after a power failure type event too. Here's some info from the last support ticket on what they suggest. Hope this helps.

After reviewing your responses, the results of your testing and going over the logs further, it appears that when you have the mesh settings configured to "Auto" then going from a WiFi backhaul to Ethernet when you plug the MR2200ac into the RT2600ac is briefly causing a loop in the network. The burst of packets caused by the loop appears to be what's triggering the protective mechanism on the switch and causing it to shut down the port connected to the Synology router.
The developers indicated that this isn't something that can be resolved/improved from the Synology side as changing the uplink settings isn't what is triggering the loop. They have stated that since setting the uplink type to Ethernet-only prevents this behavior from occurring, then using that setting for the MR2200ac is the recommended workaround.
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Otherwise, if you want to keep using the "Auto" option for the mesh uplink settings to give the mesh environment a little more fault tolerance, the developers have stated that you'll need to look into the switch's configuration to see if there are any settings that will adjust its thresholds for this traffic. The switch's documentation will likely have more details, but anything related to loop protection or flood protection will be what you're likely after. If there are thresholds that you can raise or disable, this should let the switch keep the port up even during the burst of looped packets caused by the MR2200ac connecting to the RT2600ac and switching uplink types automatically.

schumaku · Answer

Check the fine manual and look for "rate limit" or "rate limiting" and see if there are some limits configured on your switch.&nbsp;

Mykroft77 · Answer

Were you ever able to figure this out?&nbsp; I am having the exact same issue. I also have a Synology router with a mesh unit / extender connected via Ethernet to the network and about once a month my GS324TP will disable the port going to the router.&nbsp; Exact same logs as mentioned in the OP.&nbsp;And before someone things to suggest reading the manual, I have, and I have NO rate limits set in my config.&nbsp;&nbsp;&nbsp;&nbsp;&lt;14&gt; Nov 30 09:41:37 192.168.0.183-1 DOT1S[dot1s_timer_tas]: dot1s_control.c(1598) 9056 %% INFO Rate limit of 15 for 3 consecutive seconds has been exceeded on port g17&lt;12&gt; Nov 30 09:41:37 192.168.0.183-1 DOT1S[dot1s_timer_tas]: dot1s_ih.c(2010) 9055 %% WARN Diagnostically disabling interface g17 as rate limit of 15 for 3 consecutive seconds has been exceeded

soundsessential · Answer

Oh, there were supposed to be images there showing what to change but the forum did something to them. If you can't find the settings, let me know and I'll write it out.

Mykroft77 · Answer

Interesting, I did have it set to Auto and I can understand the scenario from a technical perspective I am not sure why this might happen as randomly as it was happening for me.&nbsp; While I do have power outage issues from time to time all the recent occurances of this happening had nothing to do with power cycling.&nbsp;I do, however, have the MR access point connected over a MOCA coax cable and adapters from the basement to the upper floor bedroom so that I didn't have to run new ethernet lines.&nbsp; It is gigabit and has no shared connections.&nbsp; While this method of connection has always been solid I could potentially see minor connection issues due to interference or other factors causing the ethernet uplink to drop momentarily causing the MR access point to fall back to wifi.&nbsp;I have implemented these changes and will keep an eye on things to see if it improves. Given that it only happened every month or so it may take a while to see if there is any improvement.&nbsp;Thanks for the detailed information, it is very much appreciated!!