The flexible interface (Flex I/F) is a series of tap points along the PHY/FEC datapath that allows external logic to connect to the internal hardened PCS resources as a PCS client, an OTN PHY client, or a FlexE client. The interface also permits direct access to the on-board FEC resources. The following diagram illustrates RX and TX functions in the path between the PCS Lane alignment logic to the Flex I/F port.
Figure 1. Flex Interface Tap Points
To support the multiple applications, each flex interface port has logic, controls to enable/disable the descramble/scramble logic, alignment insertion/removal logic, invalid sync-header Error block replacement, and PCS encoder/decoder logic.