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. http://www.cisco.com/en/US/partner/products/hw/optical/ps2006/prod_tech_notes_list.html 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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