CRC Error in Cisco GBIC, SFP

[ciscoman]

Hey all, we are up late at night playing around with Cisco WS-X4516-10GE and wondering why a non Cisco SFP is giving us an BAD CRC Error, figured I would share my findings with Ciscotalk.net


Title The "%GBIC_SECURITY_CRYPT-4-VN_DATA_CRC_ERROR:" error message appears in Catalyst switches Core issue The error message looks similar to this:

%GBIC_SECURITY_CRYPT-4-VN_DATA_CRC_ERROR: GBIC in port [dec] has bad crc.

This message means that the Gigabit Interface Converter (GBIC) module is identified as a Cisco GBIC module, but it does not have a valid cyclic redundancy check (CRC) in the EEPROM data. [dec] is port number or the interface in which the module is installed.
Even if the GBIC module is unrecognized by the system, the GBIC module can still operate properly, but it has limited functionality.

This problem is also termed cosmetic, indicated in Cisco bug ID CSCse25214.
Note: Cisco-approved Small Form-factor Pluggable (SFP) modules have a serial EEPROM that contains the module serial number, the vendor name and ID, a unique security code, and CRC. When an SFP module is inserted in the switch, the switch software reads the EEPROM to verify the serial number, vendor name and vendor ID, and recompute the security code and CRC. If the serial number, the vendor name or vendor ID, the security code, or CRC is invalid, the software generates the security error message and possibly places the interface in an error-disabled state.

Resolution In order to resolve this, verify that the software release that runs on the system supports the GBIC module. If the GBIC module is newer, a system software upgrade is possibly required.
Refer to LAN Switching Software page in order to download the latest Cisco IOS software release.

Problem Type Syslog error message received Problem frequency Always Catalyst switch Catalyst 2950 series switches, Catalyst 2970 series switches, Catalyst 3550 series switches, Catalyst 3560 series switches, Catalyst 3750 series switches, Catalyst 3750 Metro series switches, Catalyst 2960 series switches Catalyst switch modules Gbic Module, SFP Module Port type GBIC Switch software Cisco IOS system software Error message %GBIC_SECURITY_CRYPT-4-VN_DATA_CRC_ERROR:

[ciscoman]

I also found this, it may help


Both GBICs and SFP's are standards based in all respects so I suggest you take advantage of that and shop around.

You might be surprised at the price difference across brands for what is often the same product out of the same factory with a different sticker, for instance a 1000BASE-SX SFP has a RRP ranging from $120 inc tax to $925 inc, with the cheap one being backed by a warranty 2x that of the most expensive one!
Be careful! From Cisco website:
The use of third party SFP transceivers with Cisco devices is not supported by Cisco. Cisco-approved SFP modules have a serial EEPROM that contains the module serial number, the vendor name and ID, a unique security code, and cyclic redundancy check (CRC). When an SFP module is inserted in the switch, the switch software reads the EEPROM to verify the serial number, vendor name and vendor ID, and recomputes the security code and CRC. If the serial number, the vendor name or vendor ID, the security code, or CRC is invalid, the software generates this security error message and places the interface in an error-disabled state:
SYS-3-TRANSCEIVER_NOTAPPROVED:Transceiver on port [dec]/[dec] is not supported


Two undocumented commands that may allow you to use third party modules exist:
service unsupported-transciever
no errdisable detect cause gbic-invalid
but if things don't work, you won't get any support from Cisco.