In general, the cost of an original brand SFP module is more expensive than a 3rd party one. Take Cisco 1000BASE-SX SFP (GLC-SX-MMD) for example, the list price of Cisco is about $ 500.00, but you can easily find a 3rd party SFP modules that can take a discount at up to 90% off. As the cost of SFP transceiver keep adding up over time, many labs or companies are seeking for SFP alternatives to help cut down the costs on these expensive modules. However, a frequent customer problem with Cisco’s new line of Catalyst switches is that they do not support 3rd party (non-Cisco) SFPs – or at least they do not seem to. If you’ve just replaced your network switches and tried using any 3rd party SFPs to connect your network backbone, you’ll quickly stumble across an error similar to the following:

Error message

%PHY-4-UNSUPPORTED_TRANSCEIVER: Unsupported transceiver found in Gi1/0/0
%GBIC_SECURITY_CRYPT-4-VN_DATA_CRC_ERROR: GBIC in port 65538 has bad crc

When you see this error, it means that your Cisco Catalyst switch has just disabled the GBIC port. Why? When a SFP is inserted into a switch’s GBIC port, the switch immediately reads a number of values from the SFP and if it doesn’t like what it sees, it throws the above error message and disables the port. Simple to understand, your Cisco Catalyst switches are configured by default not to work with the 3rd party (non-Cisco) SFPs.

As we know, all SFP modules contain a number of recorded values in their EEPROM that include:

• Vendor Name
• Vendor ID
• Serial Number
• Security Code
• CRC

How To Solve This Issue & Successfully Use 3rd Party SFPs On Your Cisco Switch

When the errors displayed, many users will be very nervous and even begin to regret using the 3rd party SFPs. Is there no hope for a solution when facing such situation? Just be relax, the following content will give you some tips on it.

There are two undocumented commands which can be used to force the Cisco Catalyst switch to enable the GBIC port and use the 3rd party SFP.

3750G-Stack(config)# service unsupported-transceiver

Warning: When Cisco determines that a fault or defect can be traced to the use of third-party transceivers installed by a customer or reseller, then, at Cisco’s discretion, Cisco may withhold support under warranty or a Cisco support program. In the course of providing support for a Cisco networking product Cisco may require that the end user install Cisco transceivers if Cisco determines that removing third-party parts will assist Cisco in diagnosing the cause of a support issue.

3750G-Stack(config)# no errdisable detect cause gbic-invalid

When entering the “service unsupported-transceiver” command, the switch (eg. 3750G) will automatically throw a warning message as a last hope to prevent the usage of a 3rd party SFP. The “no errdisable detect cause gbic-invalid” command will help ensure the GBIC port is not disabled when inserting an invalid GIBC. In addition, since the service unsupported-transceiver is undocumented, if you try searching for the command with the usual method “service ?”, you won’t find it.

According to the test, Cisco 2960G, 3560G, 3750G, 4507R and 4507R-E Catalyst switches all accept both “service unsupported-transceiver” & “no errdisable detect cause gbic-invalid commands” commands without a problem. In fact, if the Catalyst switch is running IOS 12.2(25)SE and above, the undocumented commands are available.

Opinion on 3rd Party SFP Modules

People have different opinions on “Whether I should use 3rd party SFPs”. It seems a difficult question for them as the attractive price but unknown performance of the 3rd SFPs. In fact, take Catalyst 3750 Series Switches for example, starting from 12.2(25)SE release, the user has the option via CLI to turn on the support for 3rd party SFPs. However, you should remember that the Cisco TAC will not support such 3rd party SFPs. In the event of any link error involving such 3rd party SFPs the customer will have to replace 3rd party SFPs with Cisco SFPs before any troubleshooting can be done by TAC.

Thus, it is very necessary to use quality assurance SFP modules. Actually, there are some high quality SFP modules OEM vendors, such as Fiberstore. You would not worry about the compatibility of the usage. Because there is a perfect system from the production to shipment. All the products are tested before they shipped and ensure the 100% compatible and high quality. In addition, you can save more as the price is also very competitive.

Some common types of SFPs supported on Cisco Catalyst 3750 Series Switches

• 1000BASE-LX/LH SFP (GLC-LH-SM=)
• 1000BASE-SX SFP (GLC-SX-MM=)
• 1000BASE-ZX SFP (GLC-ZX-SM=)
• 1000BASE-T SFP (GLC-T=)
• 1000BASE-BX SFP 1490nm (GLC-BX-D=) (12.2(25)SEB and later)
• 1000BASE-BX SFP 1310nm (GLC-BX-U=) (12.2(25)SEB and later)