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Converting 4 fiber BLSR to 2 fiber?

Is it possible to take a 4 fiber BLSR with OC-48 cards and convert it to a 2 fiber BLSR with OC-192 cards? I can not find any type of procedure for this and I was wondering if anybody had any ideas other then deleting and starting over from scratch.


Michael Tate


Can you share which equipment are you using for 4 Fiber BLSR?  Are you talking about 15454 ? Same box can be configured in different configuration so yes it is possible to change from OC -48 4 Fiber BLSR to OC 192 2F BLSR.

If you have crossconnect capacity and slot left you can use OC 192 cards and configure new ring then take out OC 48.  If you dont have crossconnect or slot then you need more downtime for such a change. What exactly are you looking for?

Sorry, but yes it is a 15454. And your suggestion is what I was originally going to do but there are only 4 slots that can take the OC-48 cards and the OC-192 cards in my particular chassis. And since we have a 4 fiber BLSR all 4 of thos slots are already taken up.

Can we take out the protect ring cards and put in the 192 cards, move all the traffic over to them and then once the ring is complete force it into being a 2 fiber BLSR?

Will the 15454 accecpt having a 4 fiber BLSR temporarily with 48 cards on the working and 192 cards as the protect?

Is there a reason you can't upgrade the ring to 4F-BLSR with OC-192?  I don't believe there is an in-service way to complete a 4F BLSR conversion to UPSR or 2F-BLSR.

Are you a service provider where there are too many small circuits on this box or Enterprise with few big circuits?As very difficult to get downtime from customer.

As mentioned by Tom, it is going to be much more easier if you change it to OC -192 4 Fiber BLSR. See if you can edit the protection path of existing circuit. If yes then take out the protection OC 48 cards insert OC 192 and configure in OC 192. cards. Then shift working and protection circuit so your OC 192 circuit will become Working and then you can add protecten circuit after you have inserted other 2 OC 192 card. During this time your circuits are UNPROTECETD so if done in off hours will be good. I am assuming you have 60G crossconnect so you can have 4 10G cards and remaing 20G for you other cards. Most of the things here i thik can be done without downtime (If nothing happens during transition you can create a test circuit befor taking everything)

If crossconnect capacity is less then you can think of 10G 2 Fiber BLSR. check by creating circuit in  your 4 F BLSR and how flexible is your NMS/EMS if you want to edit protecetd circuit.

Let me know if you have any spare Optical card and slot available in your box. Have somehting in my mind to shift 4F BLSR to2F BLSR with less downtime. You can try first on some Demo circuit.

This is the just an overview based on some info provided.

Thank you for your replies,

As far as having enough cards to convert fully to a 4 fiber BLSR, we do not have enough, and there are no other slots available in the chassis.

I was thinking of removing the protect cards, placing the 192s in there, and then assigning those to do the protect. Then once we've done that across the ring we would switch all the working traffic to the 192s and remove the remaining 48 cards. Then I was hoping there would be a quick way (even if small downtime is required this wouldn't be terrible) to change to a 2 fiber BLSR.

Again thank you very much for all your help

Hope my message was not clear. I am not asking you have extra slot (as i already know you have not). But sometime you have some free port (If the card have many Optical port e.g 4 STM-4 on same card but you are using only 2 then other 2 you can use to create test circuit.

As you know your network better and will be knowing why 4 Fiber BLSR was chosen initially. Why you want to change to 2 Fiber BLSR now? If you are configuring one 2 Fiber BLSR now and going to add one more 2 Fiber BLSR in future then it is better if you use 4 Fiber BLSR now to avoid too many changes.

I hope you would have considered all this, but sometime we repaet things as we are not aware of the your thought process. So just writng which i would consider before change.

One OC-192 4 Fiber BLSR have the capacity of 10G with certain advantage like it can handle multiple failure.

Two Oc-192 2 Fiber BLSR again have capacity of 10G. If you dont see growth from current OC 48 to OC 192 then going with One 2 Fiber BLSR is good as it will give you OC-96 (5G) of capacity as other OC-96 is for protection.  But 4 Fiber BLSR provides protection for multiple failure.

Now regarding changing from 4 fiber to 2 Fiber. See some examples from cisco for changing from 1+1 to BLSR and BLSR to UPSR.

So you can explore how difficult it is to change from 4 Fiber BLSR to 2 Fiber BLSR. You can create some test circuit in case you have some extra OC -12 port/Oc 3 port and can be configured for 2 Fiber BLSR.

Let me know if there is any ambiguity in the message sometimes you have too many things to write and you miss the main point.

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