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high Rcv-Err in switch

chinpohpang851
Level 1
Level 1

I have this high Rcv-Err in some of the interfaces in 2960Switch. According to Cisco documentation it could be speed mismatch, but both ends were set to auto.

MPSSvrRmSW2>sh int counters errors

Port  Align-Err    FCS-Err   Xmit-Err  Rcv-Err UnderSize
Fa0/7              40         86          0       2237     0
Fa0/16              0          0          0      10659     0
Fa0/31           4171       4685    0       8995      0
Fa0/32              0          0          0          0         0
Fa0/33              0          5          0        215       0
Fa0/34              0          2          0     195446    0
Fa0/39              0          0          0         46        0
Fa0/40              0          0          0          0         0
Fa0/41              0         80          0        893      0
Fa0/42              0          0          0          0         0

At first i thought is was cable problem and I also changed the old RJ45 connector and update PC's network driver but interface 34 still high Rcv-Err. I noticed that Rcv-Err for fa0/34 remain unchange 195446, what is the command to clear this old counters and start from 0 again? I already did a shut no shut.

Thanks

3 Replies 3

ashtonpotterltd
Level 1
Level 1

I've seen many instances where setting both to Auto will still result in the speeds bouncing trying to negotiate. If that's the case here, you're going to want to hard code both ends to the highest matching speed and try again.

To clear the counters, from global EXEC mode enter the command "clear counter Fa0/34" or whatever interface you want to clear. You can simply do "clear counter" to do all interfaces.

I guess so, too. I assume the user PC auto-sensing problem so i set it to 100M Full, PC restart, looks ok. I'll monitor again. If i issue "clear counter" will restart the interface?

thanks.

 

Clear counter will not restart the interface it just clear the counters ( Errors) to 0.  Restart interface will be by using shut/no shut.

 

However most likely a Rcv-err is indicating a duplex mismatch.

Xmit-Err and Rcv-Err

This indicates that the internal port transmit (Tx) or receive (Rx) buffers are full. A common cause of Xmit-Err is traffic from a high-bandwidth link that is switched to a lower-bandwidth link, or traffic from multiple inbound links that is switched to a single outbound link. For example, if a large amount of bursty traffic comes in on a Gigabit port and is switched out to a 100-Mbps port, the Xmit-Err field might increment on the 100-Mbps port. This is because the port output buffer is overwhelmed by the excess traffic because of the speed mismatch between the incoming and outgoing bandwidths.

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