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AP sending "too large" frames

Hi! I have an AP connected to a Cisco 2950. Users connected to that AP claims that they are being disconnected from the Wireless Network many times during the day.

I checked the the port in which the AP is connected and I see that there is a slow increase of "input errors".

When I check the switch ethernet-controller for that port it show that there is also a slow increase of "Invalid frames, too large". I also get "0 giants" frames and no CRC/FCS errors.

I know that the Wireless frames are 2346 bytes by default and that the Ethernet MTU size is normally 1500 bytes. Does this has anything to do with the errors?
Any ideas on how to tweak the AP so it only send 1500 bytes frames or smaller?

Thanks!

"too large" frames and input errors on the controller

Im curious if there was a fix for this? I have a customer who has input errors on the controller interfaces (in Japan) but no errors on the switch side. We have tried several things (different ports, different cables, hard setting both sides) but continue to get these errors.

Any thoughts?

Thanks
Ck
Guru Elite

AP System Profile


Hi! I have an AP connected to a Cisco 2950. Users connected to that AP claims that they are being disconnected from the Wireless Network many times during the day.

I checked the the port in which the AP is connected and I see that there is a slow increase of "input errors".

When I check the switch ethernet-controller for that port it show that there is also a slow increase of "Invalid frames, too large". I also get "0 giants" frames and no CRC/FCS errors.

I know that the Wireless frames are 2346 bytes by default and that the Ethernet MTU size is normally 1500 bytes. Does this has anything to do with the errors?
Any ideas on how to tweak the AP so it only send 1500 bytes frames or smaller?

Thanks!




In the AP System Profile, there is a MTU parameter. change that to 1500.


Colin Joseph
Aruba Customer Engineering

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Contributor I

Re: AP sending "too large" frames

Is that the SAP MTU field?
Guru Elite

Sap mtu




Yes.



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Re: AP sending "too large" frames

Hi, I have the same problem 'input errors' on the aruba 3200 controller and no errors on the nortel bes-1020 poe switch.

jason
Guru Elite

Not the same

This is not the same thing. In this case, the giants or "errors" should be showing up on the Nortel switch instead. Errors on the Aruba controller means that the Nortel switch is passing frames that the Aruba controller cannot understand, in general. It is not the same as this thread.


Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

mat
Occasional Contributor I

Re: AP sending "too large" frames

I'm also having the same issue with the MTU size he HP switches my ap's are plugged into have "Too Many Undersized/Giant Packets on port #" i looked at my system profile and SAP MTU is blank.

what is the default setting for this if left blank?
Guru Elite

Try 1500


I'm also having the same issue with the MTU size he HP switches my ap's are plugged into have "Too Many Undersized/Giant Packets on port #" i looked at my system profile and SAP MTU is blank.

what is the default setting for this if left blank?




There is no default value. It uses MTU discovery, which is why you get the Giant packet errors. You should change it to 1500 or lower to make those errors go away.


Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Re: AP sending "too large" frames

I was refering to the second post. In which the 'controller' was having the input errors.
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