MS220-24P Port 22 started to downgrade to 100M connected to Cisco 2950

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MS220-24P Port 22 started to downgrade to 100M connected to Cisco 2950

Current version: MS 11.22

All ports set for AUTO.. I had wiring issue on Port 3 that I cleared via cleaning RJ and Cable.. after Re-enabling Port 3 (connected to MR-66 AP), Port 22 (connected to Cisco 2950 port) downgraded speed to 100M and now says "High proportion of Ethernet collisions" . The 2950 has PC and printer clients and two small Ethernet 1GB switches. The 2950 port to the MS220 is AUTO.


Trying to figure / isolate the source of the collisions.

10 Replies 10
Kind of a big deal

2950! Wooo, that's OLD! 🙂


I'm not sure the 2950 can properly do auto MDIX. You might need a crossover cable for this connection. It sounds like the two switches aren't negotiating the PHY correctly. 



Kind of a big deal

Check both sides of that connection and confirm 100% that they are both FULL-DUPLEX and 100Mbps (assuming the 2950 doesn't have a 1Gbps uplink you can use? If so use that, otherwise they should both settle on 100Mbps). If AUTO on both sides is still showing that error, try hard-coding both sides and see if it resolves.
Nolan Herring |

I just confirmed (Cisco docs) the 2950s only do 100M ports. I used them back ages ago but on site here they are managed by 3rd party (I managed the Meraki line). I see the Meraki log had "green" status so the switch port on 2950 is probably flopping/etc.


I will force MS220 port tonight after closing and check the logs / status in Dashboard and update here.

Kind of a big deal
Kind of a big deal

There are two 1G ports on the right hand end of the 24 port 2950.  

Kind of a big deal
Kind of a big deal

@ndccpf1When you said you cleaned the RJ port and cable it sounds like the switch it located in a dusty environment. You might want to unplug it and give it a good clena out with some compressed air and replace rather than clean the suspect patch lead. Rubbing alcohol on q-tip / cotton swab to gently clean the contacts also works. 


I've plugged all sorts of managed and unmanged equipment with different price ranges into Meraki gear and never had an issue with port negotiation. 


It does sound like dirty contacts to me

The switch in question actually resides in an upstairs office. The earlier AP cable issue was from the cable run ceiling height across the shop floor and terminates at an RJ jack. Then an RJ-45 cable from that jack through the wall to the outside mounted MR-66 AP.

I cleaned the RJ jack and RJ-45 cable high up at the ceiling level. It terminates back in the office at the patch panel and then to Port 3 on the MS220P where now Port 22 has the issue since the time the Port 3 AP was re-enable by me after cleaning. For this issue before cleaning the AP was going online and offline every 20 minutes.


I will confirm at the site tomorrow but the 2950 I believe has UPLINK ports that are GBIC fiber modules (option) ?

@cmr  I checked onsite today and the 2950 only has 24 10/100M ports no additionalCisco 2950.png

Kind of a big deal
Kind of a big deal

😮Someone's stolen your ports!  Or you needed the T or G models that we variously referred to above to get 2x 1G ports.  I've never seen the non suffixed model before...

I inherited the site and still uncovering things. So will focus on moving over any devices left on two remaining 2950s to the MS220s.


I also had one PC (be it Windows 7) that was only connecting on the Meraki MS220 port at 10M even thought NIC and Meraki are 1GB AUTO. I forced both NIC and Meraki port to 1GB FULL and so far looks OK (the latest LAN driver and BIOS were installed).

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