This Recommendation defines error performance parameters and objectives for international synchronous digital paths. While this Recommendation specifically addresses objectives for international digital paths, the allocation principles can be applied to the design of error performance for national or private synchronous digital paths. The objectives given are independent of the physical network supporting the path. This Recommendation is based upon a block-based measurement concept using error detection codes inherent to the path under test, the block repetition rate being in accordance with SDH technology. This simplifies in-service measurements. The events, parameters and objectives are defined accordingly. In addition to path performance assessment, tandem connection monitoring is covered. It is not required to apply this Recommendation to SDH paths using equipment designed prior to the date of adoption of this version of ITU-T Recommendation G.828 (March 2000).