System and method for the management of power supplied over data lines

1. A system for providing power over data lines, comprising a network switch including a multiplicity of ports each of which is capable of supplying power in addition to data packets;

a controllable power source which is coupled to said ports for supplying power thereto; and

a processor which is coupled to control the supply of power by said power source, and wherein said processor is programmed:

(i) to guarantee the supply of power to selected ports; and

(ii) to allow or inhibit the supply of power to ports other than said selected ports, having regard to a specified limit on the supply of power by the controllable power source and the total guaranteed power to the selected ports.

2. A system according to claim 1 wherein the processor provides for each port at least two modes, said modes being a first mode in which power to a specified value is guaranteed and a second mode in which the supply of power to the port is enabled but not guaranteed, and wherein the total supply of guaranteed power to ports in the first mode is limited to less than said limit and the power to ports in the second mode depends on the supply of power to ports in the first mode.

3. A system according to claim 2 wherein at least some of said ports are assigned an order of priority for the provision of guaranteed power and/or selective disconnection from the power source when in the second mode.

4. A system according to claim 1 , wherein the guaranteed power for a port is automatically selected on the detection of a predetermined device connected to that port, having recourse to a stored power profile for that type of device.

5. A system according to claim 1 wherein the power supplied to said other ports is varied in accordance with the actual demand for power by the ports.

6. A method of providing power over data lines from a multiplicity of ports each of which is capable of supplying power in addition to data packets, the method comprising;

supplying power from a controllable power source which is coupled to said ports; and

controlling by means of a programmed processor the supply of power by said power source, the method further comprising:

(i) guaranteeing the supply of power to selected ports; and

(ii) allowing or inhibiting the supply of power to ports other than said selected ports, having regard to a specified limit on the supply of power by the controllable power source and the total guaranteed power to the selected ports.

7. A method according to claim 6 and providing for each port at least two modes, said modes being a first mode in which power to a specified value is guaranteed and a second mode in which the supply of power to the port is enabled but not guaranteed, and wherein the total supply of guaranteed power to ports in the first mode is limited to less than said limit and the power to ports in the second mode depends on the supply of power to ports in the first mode.

8. A method according to claim 7 wherein at least some of said ports are assigned an order of priority for the provision of guaranteed power and/or selective disconnection from the power source when in the second mode.

9. A method according to claim 6 , wherein the guaranteed power for a port is automatically selected on the detection of a predetermined device connected to that port, having recourse to a stored power profile for that type of device.

10. A method according to claim 6 wherein the power supplied to said other ports is varied in accordance with the actual demand for power by the ports.