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Provisioning OSC terminations on an NCS2006 system


Hello All,

We are configuring an NCS2006 system that contains TNCE node controllers.  According to Cisco's procedure for provisioning the OSC terminations, ALS (automatic laser shutdown) should be disabled before provisioning the OSC terminations when the OSC frame type is set to Fast Ethernet but no reason is given as to why it should be disabled.  Does anyone know the reason for this and also whether ALS should be left permanently disabled or be re-enabled after the OSC terminations are configured?

Since ALS is a safety feature I'm hesitant about leaving it disabled.


Apparently it is not necessary to do this when the OSC frame type is set to OC3 or Gigabit Ethernet, only Fast Ethernet.


Any clarification on this issue would be greatly appreciated.  Thank You.


1 Reply 1


That's funny, the text box in which I'm typing suggested that I don't post and sensitive data. Good advice, I'll try and post only data that has been calloused by life and can survive the harsh wilderness of Internet forums, albeit Cisco they are.


Moving on from that pointless but hopefully entertaining tangent...


ALS, I believe the reason it is suggested to be shut down is because ALS works on receive light, when it doesn't receive, it shuts down, much like a crybaby in an argument. There is an auto restart and a manual restart for bringing links up once they are down (or for the first time). Auto restart tries every 15 sec for 90 sec then there's a backoff period after that for a short while, something like that. If you disable ALS then your optic will constantly transmit so it's easier to troubleshoot when trying to turn up or fix. After you get the span up, you can turn ALS back on.


This is just my experience with these systems and suggestions from Cisco partner install teams.

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