A communications network node 250 comprising: first 31 and second 35 optical ports, a first amplified optical section connected between the first and second optical ports and a second non-optical section connected between the first and second optical ports; in which the communications node also comprises a first optical filter 32 comprising a first path for selected optical channels at a first wavelength and second path for selected optical channels at a second wavelength; in which the communications node also comprises a second optical filter comprising a third path for selected optical channels at the first wavelength and fourth path for selected optical channels at the second wavelength; in which a first composite path through the node comprises, in an order, the first optical port 31, the first path, the first amplified optical section, the third path and the second optical port 35; characterised in that the communications node 250 also comprises an optical bypass section 255 connected between the first and second optical ports and first and second optical junctions; in which the first optical junction comprising a fifth path and a sixth path; and in which the second optical junction comprising a seventh path and an eighth path; in which a second composite path through the node comprises, in an order, the first optical port, the second path, the fifth path, the second non optical section, the seventh path, the fourth path and the second optical port; in which a third composite path through the node comprises, in an order, the first optical port, the second path, the sixth path, the optical bypass section, the eighth path, the fourth path and the second optical port; in which the node is configured to pass a first optical channel at a first wavelength over the first composite path and in which the node is configured to pass a second optical channel at a second wavelength over the second composite path during a first time period and the node is configured to pass a second optical channel at a second wavelength over the third composite path during a second time period so as to create a continuous, end-to-end optical path to allow the transfer of information by means of a stream of single photons, wherein the third composite path is different to second composite path, and wherein, during the first time period, the second composite path carries an optical service channel. in which the communications node also comprises a first optical filter 32 comprising a first path for selected optical channels at a first wavelength and second path for selected optical channels at a second wavelength; in which the communications node also comprises a second optical filter comprising a third path for selected optical channels at the first wavelength and fourth path for selected optical channels at the second wavelength; in which a first composite path through the node comprises, in an order, the first optical port 31, the first path, the first amplified optical section, the third path and the second optical port 35; characterised in that the communications node 250 also comprises an optical bypass section 255 connected between the first and second optical ports and first and second optical junctions; in which the first optical junction comprising a fifth path and a sixth path; and in which the second optical junction comprising a seventh path and an eighth path; in which a second composite path through the node comprises, in an order, the first optical port, the second path, the fifth path, the second non optical section, the seventh path, the fourth path and the second optical port; in which a third composite path through the node comprises, in an order, the first optical port, the second path, the sixth path, the optical bypass section, the eighth path, the fourth path and the second optical port; in which the node is configured to pass a first optical channel at a first wavelength over the first composite path and in which the node is configured to pass a second optical channel at a second wavelength over the second composite path during a first time period and the node is configured to pass a second optical channel at a second wavelength over the third composite path during a second time period so as to create a continuous, end-to-end optical path to allow the transfer of information by means of a stream of single photons, wherein the third composite path is different to second composite path, and wherein, during the first time period, the second composite path carries an optical service channel.