This Recommendation defines a generic framing procedure (GFP) to encapsulate variable-length payload of various client signals for subsequent transport over SDH, PDH and OTN networks as defined in [ITU-T G.707], [ITU-T G.8040] and [ITU-T G.709]. This Recommendation defines the: frame formats for protocol data units (PDUs) transferred between GFP initiation and termination points;mapping procedure for the client signals into GFP. The framing procedure described in this Recommendation can be applied to both the encapsulation of entire client frames (frame-mapped GFP) in which a single client frame is mapped into a single GFP frame, and to character-mapped transport (transparent GFP) in which a number of client datacharacters are mapped into efficient block codes for transport within a GFP frame.