Cisco BiDi / 40GBASE-SR-BD QSFP in non-Cisco switches?

[Scott Laird]

I'd really like to run 40Gbe over ~50m of OM3 LC duplex fiber, which means using BiDi optics. I have a pair of Cisco QSFPs from eBay, but they don't want to work in my Gnodal GS0018--it lights up red and says that it's an invalid QSFP.

Has anyone successfully used the Cisco QSFPs in other brands of switches, or use the fs.com BiDi optics in a Gnodal switch?

 

[azev]

I've always curious weather the bi-di qsfp from cisco would work on another gear, I think the magic happens inside the qsfp it self. But then again it may require some special firmware to make it work.

 

[Terry Kennedy]

I'd really like to run 40Gbe over ~50m of OM3 LC duplex fiber, which means using BiDi optics. I have a pair of Cisco QSFPs from eBay, but they don't want to work in my Gnodal GS0018--it lights up red and says that it's an invalid QSFP.

No Gnodal experience here, but on the Cisco side, the switch will complain even if the "magic footprints" of the vendor lock are correct, but if it is for a media type the switch doesn't understand. Some 3rd-party optic suppliers understand this and can intentionally mis-code the media type for you so the switch thinks it is one it supports (for example, coding a DWDM part as a plain-old wideband one). This probably happens with other switch manufacturers as well.

As speeds go up , fewer and fewer suppliers seem to understand this stuff. I've worked extensively with Solid Optics. They also offer a USB device which will re-code optics at the customer's site so there's no need to send the optics back if there's a compatibility issue. They do have the annoying tendancy to use "click here for a quote" instead of telling you up front how much something costs, although their eBay store does give you prices for some of their products. They're based in the Netherlands and there seems to be far less of a language barrier than there is with certain un-named Asian suppliers (who were unable to provide working Cisco SFP+ optics even after several iterations, and it wasn't clear if they even understood the issue).

 

[Terry Kennedy]

I've always curious weather the bi-di qsfp from cisco would work on another gear, I think the magic happens inside the qsfp it self.

Yup. It is a simple(ish) serial interface on the electrical side of the optics. The 2 problems are:

• Vendor lock (where a vendor has "magic footprints" to prevent use of other brands of optics). This is normally done by checksumming some subset of the EEPROM and storing the checksum in one of the "vendor use" areas.
• Enforcing overly strict adherence to standards. In addition to the textual areas (manufacturer, serial, etc.) in the EEPROM there are binary fields that indicate the form factor, connector, media type, and many other things. Some of these things are important for the switch to deal with (for example, voltage / current limits), but others aren't important except for display purposes. But the switch enforces them as well, so if a switch doesn't know about BiDi optics, or DWDM, etc. the optics get rejected even though they pass the "magic footprints" test and would probably work if those checks weren't performed. As I said in my earlier reply, some 3rd-parts suppliers get around this by intentionally mis-reporting what the optic actually is, to pretend to be one of the supported types for that switch.

There is actually a 3rd problem - the electrical side of many 10GbE optics runs at a fixed speed of 10G(-ish). The vendors seem to feel there's no need to support different speeds on optical-only ports (selectable RJ45 / SFP+ ports usually support at least 2 speeds). In the SFP (GigE) space, there are 2 kinds of 1000BASE-T SFPs - speed-converting ones and non-converting ones. Most non-10GbE Cisco gear wants the speed-converting ones. That does require a little effort in the switch firmware, at least if you want to be able to force a specific speed from the command line. At present there are no SFP+ with a RJ45 connector, so the issue hasn't really come up. All of the "dual speed" fiber SFP+ optics I've seen are non-speed-converting - they require the switch port to support both speeds. And support is limited - as an example, there are dual-speed SFP+ optics for some Dell switches, but they don't work (at either speed, due to issue 2 above) in most Dell switches.

 

[Jerry Renwick]

I have used the fs.com Compatible Cisco Bidi transceivers on Cisco switch, and it worked. Before I purchase their, I have checked several time with the salesperson about the compatibility problem. She said it is tested assured. Therefore it is better to figure out the compatibility issue before making a product choice.

 

[azev]

I have used the fs.com Compatible Cisco Bidi transceivers on Cisco switch, and it worked. Before I purchase their, I have checked several time with the salesperson about the compatibility problem. She said it is tested assured. Therefore it is better to figure out the compatibility issue before making a product choice.

oh nice, good to know... fs sells super cheap sfp it is almost unbelievable. Maybe I am just too naive on the fact that vendor like cisco is racking so much $$ from selling sfp's.

 

[pc_doom]

I have bought several Cisco compatible BiDi transceivers from fs.com. They are working perfectly with my Cisco swtich, but I don't know whether they are available for your Gnodal switch. Maybe you can contact the salesman whether they are compatible or not.

 

[Terry Kennedy]

I have used the fs.com Compatible Cisco Bidi transceivers on Cisco switch, and it worked. Before I purchase their, I have checked several time with the salesperson about the compatibility problem. She said it is tested assured. Therefore it is better to figure out the compatibility issue before making a product choice.

Unfortunately, my experience with them for DWDM SFP+ (for Cisco 4500-X) was less successful. That's why I went to Solid Optics. There are a lot of subtleties in the way different Cisco products handle optics, and just because it works on one Cisco product doesn't mean it will work on another. Sometimes even Cisco has different part numbers for the same optics on different products and they aren't interchangeable. That's one of the reasons I find the ability to re-code parts on-site with the Solid Optics tool so valuable.

 

[OpticalTransceiver]

I'd really like to run 40Gbe over ~50m of OM3 LC duplex fiber, which means using BiDi optics. I have a pair of Cisco QSFPs from eBay, but they don't want to work in my Gnodal GS0018--it lights up red and says that it's an invalid QSFP.

Has anyone successfully used the Cisco QSFPs in other brands of switches, or use the fs.com BiDi optics in a Gnodal switch?

I am working in a CM manufacturing SFP+/QSFP+/QSFP28/CFP for major switch vendors like CISCO, HW, ZTE, Nokia and Ericsson. The issue why transceivers can not run in the switch is because the EEPROM information in A0h and A2h area in the transceiver. The switch will read these area to check if it is the "genuine" optics.

To solve this requires two thing:
1. you need to know the EEPROM information that the switch vendor ask the OEM to write in the optics.(Somecase you can read the EEPROM and just copy it.)
2. you need to know the password from the CM of the switch vendor to have permission to write in the EEPROM in any transceivers.

The reason why the switch vendor doing this is because:
For example, 10G multi-mode 850nm 300meter SPF+ optics they purchase around $13.00 per unit from us and sell it hundred dollars and a 100G QSFP28 CLR4 2km they purchase around $800.00 per unit form us and sell it thousands. The optics contributes a lot of interest to these companies.
Also, they invest a lot to monitor the CM factory to ensure the quality and have more control on supply chain when market demand grows dramaticly.