The present invention relates to methods and arrangements to measure network performance. The method comprises the following steps:—Transmitting via a communication network (IP) payload packets (21-24) from a sending node (GGSN/A) to a receiving node (GGSN/B).—Generating at the sending node (GGSN/A) a send specification (s21-s24, sid21-sid24) for each of at least one selected packet (21-24) of the transmitted payload packets (21-24).—Generating at the receiving node (GGSN/B), a receive specification (r21-r22, rid21-rid22, siz21-siz22) for each of at least one selected packet (21-22) of the transmitted payload packets (21-24).—Bringing together generated send specifications (s21-s24, sid21-sid24) and generated receive specifications (r21-r22, rid21-rid22, siz21-siz22).—Estimating network performance by utilizing corresponding specifications (s11-s12, r11-r12, siz21-siz22) of the brought together specifications.