High "Rx Over" Error on a Port

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  • Updated 1 month ago
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Hi,

I have a port on a switch that is not congesting and the utilization is lower than 20 percent. Yet, Rx over error is so much - can run into millions in minutes:

Port      Link     Rx      Rx      Rx        Rx      Rx         Rx         Rx   
          State    Crc    Over    Under     Frag    Jabber      Align      Lost 
================================================================================
Port> A       0   9757092        0        0        0          0          0
================================================================================

Any advise please.
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Posted 1 month ago

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Ash Curtis, Employee

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Is the neighbouring device sending jumbo frames? If it is, and jumbo frames are not enabled on the receiving port, you will see Rx Over incrementing in this way. 

This article from our KB explains how to enable jumbo frames and configure the MTU size in EXOS:

https://gtacknowledge.extremenetworks.com/articles/How_To/How-to-enable-jumbo-frames
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Bnoba CEO

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Hi Ash,

Thanks for your response. But jumbo frame is enabled on both devices.
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Eric Burke

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Bnoba, I'd dig a bit deeper in the jumbo frame configs. The only way I'm aware of you getting this error is for a "receive overrun". Issue a "show port xx info detail" command on the ports in question and make sure they both enabled (you'll see "jumbo:" toward the middle of the list.
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Jumbo:  Enabled, MTU= 9000

Jumbo is enabled.
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Brad Parker, Technical Support Engineer

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Might want to try configuring to 9216 instead of 9000.
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Naresh, Employee

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Hi Bnoba,
Did you tired changing the cable and SFP if connected to the port?
If not, please swap the cable and the SFP if connected to the port and check if you area still seeing the RX CRC errors.
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Hi Naresh,

Thanks. I would explore this option.