PoE powered device with link layer startup processor
A Power over Ethernet (PoE) Powered Device ( 60 ) is described herein that includes an auxiliary processor ( 62 ) that negotiates a power level with a PoE Power Sourcing Equipment using a first link layer ( 650 ), means for holding the PoE Powered Device in a low power state, and a second link layer ( 50 ) that allows the main processor to communicate over the Ethernet.
1. A Power over Ethernet (PoE) system comprising:
a PoE Power Sourcing Equipment (PSE), including a PSE Controller, connected to a first end of an Ethernet cable;
a PoE Powered Device (PD), including a PD Controller, connected to a second end of the Ethernet cable, wherein the PoE PD further comprises:
a main processor,
an auxiliary processor configured to negotiate a power level with the PoE Power Sourcing Equipment using a first data link layer in a communications process that is conducted as a software based link layer discovery protocol classification scheme, and further configured to hold the PoE Powered Device in a low power state, and
a second data link layer in a communications process that is conducted as a software based link layer discovery protocol classification scheme, wherein
the main processor is configured to communicate over the Ethernet cable using the second data link layer; and
a switching device configured to receive a signal from the auxiliary processor that transfers power from the auxiliary processor to the main processor after the power level negotiation.
2. The system according to claim 1 , wherein the switching device comprises:
a power relay configured to direct electrical power supplied by a DC-DC converter to either the main processor or the auxiliary processor.
3. The system according to claim 1 , wherein the switching device comprises:
a switching transistor configured to direct electrical power supplied by a DC-DC converter to either the main processor or the auxiliary processor.
4. A Power over Ethernet (PoE) Powered Device (PD) comprising:
a main processor;
an auxiliary processor configured to negotiate a power level with a PoE Power Sourcing Equipment using a first data link layer in a communications process that is conducted as a software based link layer discovery protocol classification scheme, and further configured to hold the PoE Powered Device in a low power state;
a second data link layer in the communications process that is conducted as a software based link layer discovery protocol classification scheme, wherein the main processor is configured for network communications using the second data link layer; and
a switching device configured to receive a signal from the auxiliary processor that transfers power from the auxiliary processor to the main processor after the power level negotiation.
5. The device according to claim 4 , further comprising:
a non-volatile memory associated with the auxiliary processor and configured to store a MAC address associated with the main processor, and a required PoE power level.
6. The device according to claim 4 , wherein the auxiliary processor is selected from the group consisting of a central processing unit (CPU) integrated circuit, and a state machine implemented on a field programmable gate array (FPGA).
7. The device according to claim 4 , wherein the switching device comprises:
a power relay configured to direct electrical power supplied by a DC-DC converter to either the main processor or the auxiliary processor.
8. The device according to claim 4 , wherein the switching device comprises:
a switching transistor configured to direct electrical power supplied by a DC-DC converter to either the main processor or the auxiliary processor.
9. The device of claim 4 , further comprising:
an inter-processor communication bus connected between the auxiliary processor and the main processor, and wherein;
the inter-processor communication bus is configured to transfer status information from the auxiliary processor to the main processor prior to transferring power.
10. The device of claim 9 , wherein
such status information includes at least one or more of negotiated speed, and duplex setting.
11. A powered device (PD) controller suitable for use within a Power over Ethernet (PoE) PD, the PD controller comprising:
powered device controller circuitry;
a physical medium dependent sublayer; and
a data switch operable to selectively connect either a first physical medium attachment sublayer or a second physical medium attachment sublayer to the physical medium dependent sublayer; and
a switching device configured to receive a signal from the auxiliary processor that transfers power from the auxiliary processor to the main processor after the power level negotiation.
12. The PD controller according to claim 11 , wherein each of the powered device controller circuitry, physical medium dependent sublayer, and data switch are collocated on an integrated circuit chip.
13. A method for initializing a Power over Ethernet (PoE) connection comprising:
(a) connecting a PoE power sourcing equipment (PSE) to a PoE powered device (PD), the PoE PSE comprising a PSE controller;
(b) performing, at the PSE controller, a first power level classification in accordance with IEEE 802.3af;
(c) booting up an auxiliary processor located in the PD;
(d) determining whether a second power level classification, in accordance with IEEE 802.3at, has been performed;
(e) negotiating, when the second power level classification has not been performed, by the auxiliary processor, a power level classification using a link layer discovery protocol (LLDP);
(f) booting up a main processor in the PD; and
(g) receiving a signal from the auxiliary processer at a switching device that transfers power from the auxiliary processor to the main processor after the power level negotiation.
14. The method according to claim 13 , further comprising:
enabling power to be sent to the main processor by the auxiliary processor prior to the step of booting up the main processor.
15. The method according to claim 13 , further comprising:
enabling a data transfer switch by the auxiliary processor subsequent to the step of booting up the main processor.
16. A Power over Ethernet (PoE) Powered Device (PD) comprising:
a main processor;
an auxiliary processor configured to negotiate a power level with a PoE Power Sourcing Equipment using a first data link layer in a communications process that is conducted as a software based link layer discovery protocol classification scheme, and further configured
to transfer power of the PoE Powered Device from a low power state to a high power state by transmitting a power transfer control signal to a power supply following the power level negotiation with the PoE Power Sourcing Equipment;
a second data link layer in the communications process that is conducted as a software based link layer discovery protocol classification scheme, wherein the main processor is configured for network communications using the second data link layer; and
a switching device configured to receive a signal from the auxiliary processor that transfers power from the auxiliary processor to the main processor after the power level negotiation.
17. The device according to claim 16 , further comprising:
a non-volatile memory associated with the auxiliary processor and configured to store a MAC address associated with the main processor, and a required PoE power level.
18. The device according to claim 16 , wherein the auxiliary processor is selected from the group consisting of a central processing unit (CPU) integrated circuit, and a state machine implemented on a field programmable gate array (FPGA).
19. The device of claim 16 , further comprising:
an inter-processor communication bus connected between the auxiliary processor and the main processor, and wherein
the inter-processor communication bus is configured to transfer status information from the auxiliary processor to the main processor prior to transferring power.
20. The device of claim 19 , wherein
such status information includes at least one or more of negotiated speed, and duplex setting.