Fiber Automatic Transfer Switch

I am new to the world of layer-1optical failover solutions. I came across the NTT-AT Intelligent Optical Switch [1] while researching products that can be used to automatically switch a fiber path on link failure. Do any of you have experience with this particular product? Can anyone recommend a similar 1U product that can transfer an optical signal to a secondary path when there’s been a break?

Tim Nowaczyk


Essentially, all you're looking for is a 1+1 optical splitter on transmit and photonic switch on receive.
Many vendors make this, including from cheap sources[1] to optical protection cards from big vendors[2].

I'd also recommend Huhber+Suhner (Cube Optics) - these guys can customize optical line protection package, we use them ourselves.



Hi Tim,

I want to dissuade you from using this architecture. When you have two
paths, it's important to keep them both lit so that you can detect
faults and correct them in a timely manner. The most intractable
problem with active/failover architectures is that the failover proves
inoperable when it's needed. The old backup tape that doesn't restore.
Keep your layer-1's active all the time and do fault handling at a
higher layer.

Bill Herrin

They have their uses - mostly protecting layer 1 products sold as such but also protecting things that can't be protected easily at higher levels such as RFoG. However, if you're using them to sell protected layer 1 products (protected waves or OTN paths, basically), it's important to make sure you have at least some active traffic on the link at all times that can be monitored for exactly the reasons Bill alludes. For a lot of networks, this can end up being just the OSC, but as that's often not subject to the full photonic path, I'd likewise advise against that being the case and to make sure you have at least some fully "in band" traffic that can be monitored along both legs.