This Recommendation defines error performance parameters and objectives for international ODUk paths transported by the Optical Transport Network (OTN) as described in ITU-T Rec. G.709/Y.1331. While this Recommendation specifically addresses objectives for international ODUk paths, the allocation principles can be applied to the design of error performance for national or private ODUk paths. This Recommendation is based upon a block-based measurement concept using error detection code (EDC) and EDC usage inherent to the path under test; the block repetition rate being in accordance with OTN technology in accordance with ITU-T Rec. G.709/Y.1331. This simplifies in‑service measurements. The events, parameters and objectives are defined accordingly. In addition to path performance assessment, tandem connection monitoring is covered.