The Xelic Frame Mapped Generic Framing Procedure Core (XCGFPFM) will frame and encapsulate/de-encapsulate client traffic in compliance with ITU-T G.7041/Y.1303. GFP Transmit and Receive Processors function independently to provide full duplex operation at data rates up to 2.5Gb/s with a common register interface for core configuration and control. GFP processing in either direction can be throttled or suspended at any time by deasserting transmit and/or receive enable inputs. This feature enables the XCGFPFM core to be used in systems with variable line data rates.
The GFP transmit processor accepts incoming frame mapped data packets (Ethernet, PPP, MAPOS, or proprietary packets) or management packets from an external FIFO interface and packages them into GFP client data frames. GFP control frames (idles) are inserted to achieve frame rate adaptation when incoming client packet information is not available. GFP payload information is optionally scrambled using a x43 + 1 self synchronous scrambling algorithm. A 4-byte GFP core header is added each frame and is optionally scrambled using a Barker like sequence. A test feature is provided to allow for the self generation of GFP frames and the corruption of core and/or payload header HEC fields.
The GFP receive processor performs frame delineation and optionally corrects core and payload header single bit errors (multiple bit errors are detected). Interpreters are implemented to detect control frames (idles), client management frames, client data frames, corrupted frames, and invalid client data and management frame conditions.
The XCGFPFM provides a generic register interface for access and configuration of internal memory mapped locations. This interface is shared between GFP transmit and receive processors with addressing being mapped from independent base addresses. The implementation of a generic register interface allows for easy integration with other cores that may be contained in a customer application.