Methods and apparatus for synchronizing a first clock of a transmit node and a second clock of a receive node in a packet network are provided. Receive time stamps are generated for transferred packets at a receive node in-accordance with the second clock. Propagation delay variation is filtered from receive time stamp intervals through a filter in accordance with a frequency of the second clock. The filtered receive time stamp intervals and transmit time stamp intervals of the transferred packets are input into a phase locked loop to generate a new frequency for the second clock. The filter and the second clock are updated in accordance with the new frequency for synchronization with the first clock of the transfer node.