We have several BX SFPs in my network and I love them. We're limited on the amount of fiber we can get between buildings (each pair costs $250/month) so the mismatched laser solution gives us redundancy and extra bandwidth all at once. For the uninitiated, the BX solution consists of one 1310nm laser on one end and a 1490nm laser on the other with a special mirror in the SFP that allows both frequencies to traverse one strand of fiber at a time enabling bidirectional communication on a single strand of fiber instead of the usual fiber pair.

The problem is that as our network grows, so do our bandwidth requirements, particularly for a couple of data centers that aren't at the core of our network. Is there any reason why there aren't any BX 10Gig SFP+ modules around? I can't seem to find any, at least. Is there a downside to using BX-style single-strand connections? I mean, at least you don't have to worry as much about UDLD, right?

Is there a similar technology for 10Gig that I'm not aware of?

  • I would look closely at the cost comparison between going to specialty 10G optics vs paying the extra $250/month for another fiber pair and using the run-of-the-mill 10G optics. I know one is a recurring cost, and the other isn't, but you'd also be more likely to find spares in a pinch with a common optic (just one reason I can think of off hand). Jan 2, 2014 at 21:14
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    Informational : You should consider fiber sheath and trough diversity for any solution you cook up. Backhoes do nasty things to your career if you haven't considered this angle. I operate a large campus network, and we still run into issues with construction and legacy path diversity decisions Jan 2, 2014 at 21:23
  • @BrettLykins - Our 1G BX connectors cost the same as our traditional 1G connectors, so there's no change in upfront cost for us. I'm not sure if that's true across the industry, but it is for us with our supplier. Jan 2, 2014 at 21:27
  • @MikePennington - Our fiber optic cabling outside of the building is maintained by a different department in our organization (city government). They seem to do a good job of maintaining it and are pretty smart when planning initial installations. Thanks for the head's up! Jan 2, 2014 at 21:28
  • I've seen 10G on a single strand provided by a service provider but not sure exactly what hardware was used - I believe it was from Transition Networks
    – user3748
    Jan 3, 2014 at 9:29

3 Answers 3


10G BX SFPs do exist! I don't know if you can get Cisco branded ones (if you're using cisco switches) but I have found generic ones before. Just google for "SFP-10G-BXU-10km" (or SFP-10G-BXD-10km) and you should find several suppliers. The supplier I got a quote from makes them "cisco compatible" and "hp compatible" so you should have no problem having them recognized by your switch.

Good luck!


Have you looked at using a separate external mux? I've run parts of our rings on pairings of ordinary (but colored) 10G optics and passive CWDM muxes with a single strand on each side. This let us also do multiple parallel links at the same time (we used 8 channel muxes).


A passive wavelength-division multiplexer, such as a CWDM or DWDM mux, would probably be your best bet; this is how Service providers supply fiber especially longer distances from their local Hub site.

It is probably a larger investment upfront but it would also allow you to get more out of your existing leased fibers. This is also assuming that your lease fibers are on piece of glass and are not muxed already.

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