Abstract: Novel techniques are disclosed for continuously monitoring parameters of delay between two nodes in a telecommunication network such as an ATM or frame relay network. The techniques use measurement cells, i.e. test cells, test frames, performance management ATM OAM cells, or performance management frame relay frames. These cells or frames contain a timestamp indicating the time a cell or frame is sent and a delay value indicating a difference between reception and transmission times of the cell or frame. Near-end and far-end as well as unidirectional or bidirectional monitoring can be performed, to support single-ended monitoring.