Absence of logic link between RPR interfaces of some sites, while physical link is up.
On-board indicators: Optic link between site is in up state. WRAP led is on.
Display interface RPR command shows on fault sites only one rpr interface
Was checked installation manual.
Was found that RPR LPU boards have to be paced in to specific slots. The card in the left slot is called side A, and the card in the right slot is called side B. And in the same time and side A card must be installed in the slot with an odd number, side B must be installed in the slot with an even number. So boards can only occupy slots in the sequence of "1&2", "3&4", etc.
Boards position on two site was changed.
Side A of one site don't correspond site B of other
We should pay attention for boards positioning, read installation manuals and check riggers work.