For more details, please see ourCookie Policy.

Fibre Channel (SAN)

New Member
Posts: 1
Registered: ‎01-29-2019

Error on ISL port after sfp and cable change

[ Edited ]



I've a lot of CRC errors on my ISL port between my two D300. We have changed sfp and cable but I still have error ! They appears after a major power issue in all city.


I want to move sfp and cable to a new port and so change my ISL port, is it possible to perform that ?


In case of, we have also done a fastboot on the switch.


Don't have any other idea about this issue...

Tks in advance.



Super Contributor
Posts: 320
Registered: ‎04-04-2018

Re: Error on ISL port after sfp and cable change

[ Edited ]



are you having only CRC errors or do you see another type of errors on the links?

Please mark this response as "Accept as Solution" if it answers your question.

Marian Bezeg
Frequent Contributor
Posts: 86
Registered: ‎05-26-2010

Re: Error on ISL port after sfp and cable change

[ Edited ]

First, the CRC errors need to be confirmed they are happening between the ISL ports and

not originating from a device attached to either switch. 


If the CRC error on the ISL port has incremented for counter "CRC" and "CRC g_eof"

then the CRC happened between the ISL ports.


If the CRC error on the ISL has incremented for counter "CRC" but "CRC g_eof" count is 0,

then the CRC happened before the frame reached the ISL port.


Use command porterrshow to observe CRC and CRC g_eof.


So,  determine if the CRCs are occurring between ISLS or before the frame is forwareded

to the ISLs.


1) Clear the fc counters (cmd: statsclear) on each switch

2) Clear the ASIC counters (cmd: slotstatsclear) on each switch

3) Monitor for CRCs and CRC g_eof counters for ISL ports using command:  porterrshow

       If CRC increments but not CRC g_eof, the frame damage happened before the ISL port.

      Check the other ports on the switch that could be sending frames across the ISL.


      If CRC and CRC g_eof increment, I would check the output of  "sloterrshow" to see

      if there is any internal ASIC issue causing CRCs.


 4) Check the SFP tx and rx power levels too:     sfpshow x/y

      <My typical threshold for 4 and 8Gb is power level is power should be above 200uW>

The comments and advise included are the author's and do not mirror the views and opinions of any company. Any comments, advise, statements or references are without warranty, liability or claims of expertise. You should seek the assistance of the professional entity for subject matter being pursued.
Posts: 7
Registered: ‎01-29-2019

Re: Error on ISL port after sfp and cable change

That is highly useful information. Thanks for the post!

Join the Broadcom Support Community

Get quick and easy access to valuable resources across the Broadcom Community Network.