A method for performing a time measurement on a packet flow transmitted through a communication network from a first measurement point to a second measurement point, said method comprising: a) at said first measurement point, while said packet flow is transmitted, dividing said packet flow into first packets (Pki) transmitted during first periods (T, T, T,...) and second packets (Pki) transmitted during second periods (T, T,...) which alternate in time with said first periods (T, T, T,...); b) during a certain period (T(k)), while said first packets (Pki) are transmitted, at said first measurement point marking said first packets (Pki) by setting a feature of each one of said first packets (Pki) to either a first marking value (Vc) indicating a first packet (Pki) to be subjected to time measurement or a second marking value (Vd) indicating a first packet (Pki) not to be subjected to time measurement, and generating a transmission timestamp for each one of said first packets (Pki) marked by said first marking value (Vc), said marking comprising: - setting a predefined minimum inter-transmission time (Tx) shorter than a duration (Tb) of said period (T(k)); and - checking whether said minimum inter-transmission time (Tx) lapsed since transmission of the last packet (Pki) marked by said first marking value (Vc) and, in the affirmative, marking said first packet (Pki) by said first marking value (Vc); c) at said second measurement point, identifying said first packets (Pki) marked by said first marking value (Vc) and, for each one of said first packets (Pki) marked by said first marking value (Vc), generating a reception timestamp; d) after expiration of said period (T(k)), performing said time measurement based on said transmission timestamps and said reception timestamps of said first packets (Pki) marked by said first marking value (Vc). a) at said first measurement point, while said packet flow is transmitted, dividing said packet flow into first packets (Pki) transmitted during first periods (T, T, T,...) and second packets (Pki) transmitted during second periods (T, T,...) which alternate in time with said first periods (T, T, T,...); b) during a certain period (T(k)), while said first packets (Pki) are transmitted, at said first measurement point marking said first packets (Pki) by setting a feature of each one of said first packets (Pki) to either a first marking value (Vc) indicating a first packet (Pki) to be subjected to time measurement or a second marking value (Vd) indicating a first packet (Pki) not to be subjected to time measurement, and generating a transmission timestamp for each one of said first packets (Pki) marked by said first marking value (Vc), said marking comprising: - setting a predefined minimum inter-transmission time (Tx) shorter than a duration (Tb) of said period (T(k)); and - checking whether said minimum inter-transmission time (Tx) lapsed since transmission of the last packet (Pki) marked by said first marking value (Vc) and, in the affirmative, marking said first packet (Pki) by said first marking value (Vc); - setting a predefined minimum inter-transmission time (Tx) shorter than a duration (Tb) of said period (T(k)); and - checking whether said minimum inter-transmission time (Tx) lapsed since transmission of the last packet (Pki) marked by said first marking value (Vc) and, in the affirmative, marking said first packet (Pki) by said first marking value (Vc); c) at said second measurement point, identifying said first packets (Pki) marked by said first marking value (Vc) and, for each one of said first packets (Pki) marked by said first marking value (Vc), generating a reception timestamp; d) after expiration of said period (T(k)), performing said time measurement based on said transmission timestamps and said reception timestamps of said first packets (Pki) marked by said first marking value (Vc).