Do you have DCC interconnectivity between the 15454s over the OC-48 links from the two vendors?
The OC-48 links to the two vendors would each be unprotected. When you create a circuit from one 15454 to the other, the circuit would be set-up to use Path Protection (this is the default when creating a circuit). The Path Protection takes the input at 15454 #1 and bridges it, creating two circuits; one would traverse one OC-48 link and one would traverse the 2nd OC-48 link. At 15454 #2, the two circuits are received on the two OC-48 ports and come together in a switch (in the cross-connect card), which determines which path to use (which has a better signal quality) and connects it to the output port.
Using only one OC-N card in each node creates a single point of failure. So the system would only be able to correct for a link failure (single fiber break, one vendor's network down, etc.). Instead of using a 12-port MRC card, a 4-port MRC or a single OC-48 port card would be more appropriate.
Review the user documents for info on Path Protection or PPMN (Path Protected Mesh Networking).
