A method in a network system capable of node-to-node time-transfer for synchronizing a respective local clock of an originating server and at least one client device or other server by means of two-way time transfer, wherein two-way time transfer comprises providing a local clock signal in the originating server, and for each of said at least one client device or other server which is connected to the originating server: receiving in the originating server a local clock signal of the at least one client device or other server; estimating a time difference at the originating server based on the local clock signal of the originating server and the received clock signal from the at least one client device or other server; transferring said local clock signal of the originating server and the estimated time difference at the originated server to the at least one client device or other server; estimating a time difference at the at least one client device or other server based on a local clock signal of the at least one client device or other server and the received clock signal of the originating server; and adjusting the local clock signal of the at least one client device or other server based on the received estimated time difference at the originating server, the estimated time difference at the at least one client device or other server, and the local clock signal of the at least one client device or other server, said method characterized by comprising a first mode in which the two-way time transfer is selectively employed, and by further comprising employing a second mode in which only said local clock signal of the originating server and said local clock signal of the at least one client device or other server are exchanged between said originating server and said at least one client device or other server. receiving in the originating server a local clock signal of the at least one client device or other server; estimating a time difference at the originating server based on the local clock signal of the originating server and the received clock signal from the at least one client device or other server; transferring said local clock signal of the originating server and the estimated time difference at the originated server to the at least one client device or other server; estimating a time difference at the at least one client device or other server based on a local clock signal of the at least one client device or other server and the received clock signal of the originating server; and adjusting the local clock signal of the at least one client device or other server based on the received estimated time difference at the originating server, the estimated time difference at the at least one client device or other server, and the local clock signal of the at least one client device or other server, said method characterized by comprising a first mode in which the two-way time transfer is selectively employed, and by further comprising employing a second mode in which only said local clock signal of the originating server and said local clock signal of the at least one client device or other server are exchanged between said originating server and said at least one client device or other server. <EOS>