On 2018-03-21 17:24, Job Snijders wrote:
Silly question perhaps, but why would you do BFD on dark fiber?
Simple paranoia perhaps? Just because you only have layer 1 equipment (transponders) right now, doesn't guarantee that you won't need to stick in a layer 2 switch in the path tomorrow, and if you already have BFD running, you won't forget to add it at that time. As a real-life example: we have dark fiber from our main campus to another campus in the neighbouring city, and from there we have dark fiber to a partner a few kilometers further away. We run wavelengths the entire way from the main campus to our partner (being demuxed and muxed back at the sub-campus). At one point, the fiber needed to be rerouted, and then the attenuation became to high for one of the CWDM wavelengths. Solution: put an ethernet switch at our sub-campus to act as a kind of amplifier for that wavelength. (This was using 120km CWDM gigabit transceivers directly in the routers at each end. We have since retired those and use 10 gigabit DWDM with transponders and EDFA amplifiers.) Yes, it was a duct-tape solution, but it was cheap and got the work done. :-) /Thomas Bellman