This document describes a passive method to perform packet loss, delay and jitter measurements on live traffic. This method is based on Alternate Marking technique, also called PNPM (Packet Network Performance Monitoring). It has been invented and engineered in Telecom Italia. This technique can be applied in various situations (e.g. [I-D.bryant-mpls-synonymous-flow-labels], [I-D.ietf-bier-mpls-encapsulation]). The Telecom Italia use case is explained in order to give an example and show the method applicability. The previous IETF drafts by Telecom Italia about this technique were: [I-D.cociglio-mboned-multicast-pm] and [I-D.tempia-opsawg-p3m].