I have a problem with my HP 2920-48G Switch and my Apple air port extreme 6th gen. The problem is: once the apple wifi access point (that is all I use the Airport for is a Wifi Access Point) connects to the network, I get errors on the HP 2920 of "multiple devices lost connection" and other errors that point to mismatched port speeds between the two devices. I think the problem is with the port negotiations on the two network devices. My question is does anyone know which setting or command can enable better communication between the two different network devices? I know on the Airport there are not many network settings, but the HP might have something in the command line that can help?

I appreciate any advice and if anyone else has had problems with Apple wifi and HP 2920 switches. I used to run Cisco switches, but decided to go with HP switches and these problems started after I upgraded both the core network (HP 2920) and the Airport. Do these devices just not play well together?

Update Dec 27, 2014: HP Command line Interface print out

14:50:34 00328 FFI: port 45-Excessive jabbering/fragments. 
14:51:15 00328 FFI: port 45-Excessive jabbering/fragments. 
14:52:16 00328 FFI: port 45-Excessive jabbering/fragments. 
14:52:57 00328 FFI: port 45-Excessive jabbering/fragments. 
15:39:46 00328 FFI: port 45-Excessive jabbering/fragments. 
15:53:26 00328 FFI: port 45-Excessive jabbering/fragments. 
15:58:13 00328 FFI: port 45-Excessive jabbering/fragments. 
16:01:17 00328 FFI: port 45-Excessive jabbering/fragments. 

Above is a copy of the logs on the HP 2920. I am wondering if there is any setting in the command line that can help this? Or do these two network devices not work good together and if I should just invest in another wifi solution? I have changed all of the port settings on the HP GUI ie. changed the port speeds from auto to 1000-auto and everything in between. I do not know how to access these setting via the HP CLI and I am hoping someone has had a similar problem with HP and Apple Airport Extreme wifi. Any advice would be greatly appreciated with this issue and I thank anyone who has taken the time to look at this problem for me.

Best regards,

  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Aug 10, 2017 at 23:17

2 Answers 2


The event message means that the connected device is incessantly transmitting either oversized packets with CRC errors (jabbering), or fragmented frames.

This is unlikely to be caused by a duplex mismatch. The usual symptoms of DM are Excessive CRC/Alignment errors, link flapping and port defaulting to HDx mode.

The switch isn't usually the root cause either, it's just reporting what it is receiving on the port. The usual root causes for jabbering are failure of the physical connector, firmware or driver of the connecting device; or bad cabling / patch panel.

Here's what to do about this:

  1. Ensure that both devices are running current SW/FW to exclude SW-related issues
  2. Use a brand new cable directly connected between the Airport and the switch to exclude faulty cabling / patch panel
  3. Verify that both device ports are set to Autonegotiation - this is default setting in most networking devices, I'd expect Airport to use that as well
  4. Test by setting both ends of the link to fixed 100FDx or 1000FDx mode - this will exclude negotiation errors
  5. Test in one of the first 12 ports - this will exclude failing switch port, or port controller
  6. If possible test with another Airport

Do the tests one at a time, and you'll identify the point of failure.

If not, or if the failure appears to be on the switch, call support. That 2920 carries a lifetime warranty (if purchased from a legit HP reseller) so you only pay for a local call.

Applicable HP Knowledge base articles:


Here are something you can try on CLI (I donot have a airport extreme).

config t
inter 45
speed-duplex 1000-full

The error messages you listed are Switch complaining of the CSC and normally caused by duplex mismatch. Plus what is the setting on your switch for port 45?

It seems like it might not be a switch issue now. Again I never used airport before. I guess you are bridging the 2 to increase the coverage? If so, I would recommend you to move the 2 airports closer to each other. Normally 20% overlap of the coverage is recommended.

  • I have set it to each setting in the HP gui from 10HDx to Auto-1000 everything in between and I still lose connectivity between the 2 airports and the HP switch. The problem is I am connecting two Airport switches to span a 400 meter distance wirelessly. I should have put that in my initial post. So here is the setup. I have one (core HP 2920) that connects to one Airport which connects to another airport 400M away. My problem is the outer AP disconnects and I get those types of messages. I have tried every setting on the HP and there are no configurable speed settings on the Apple AP.
    – Webdevndn
    Jan 5, 2015 at 23:29
  • Edited my answer above. Auto-1000 can not guarantee to give you full duplex.
    – m1xed0s
    Jan 6, 2015 at 13:10

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.