ADJUSTING POWER PRIORITY IN A POWER-OVER-ETHERNET SYSTEM BASED ON THE AVAILABILITY OF AN ALTERNATIVE POWER SOURCE

Abstract

Power-over-Ethernet (PoE) power supply device (PSE) (110) comprising the following: Ports (140) that can be connected via respective communication links to PoE-powered devices (PDs) (200) to power the PDs and exchange communications with them; and a control circuit (150) configured to operate in a state where a plurality of PDs (200) are connected to the terminals: from the multitude of PDs, link-layer protocol communications (160) are received, each comprising an alternative power field (161) indicating whether the PD that sent the respective communication has an alternative power source; and sets power priorities for the multitude of PDs at least partially based on the respective alternative power fields of the communications, in order to reduce a power priority of a first PD of the multitude of PDs relative to a standard value for the first PD if the first PD has an alternative power source (202).

Description

INTRODUCTION

[0001] Power over Ethernet (PoE) enables the transmission of data and power signals over a single Ethernet cable. This allows a PoE-enabled electronic device to communicate with a network and receive power over the same cable, offering greater flexibility in device placement (e.g., the device no longer needs to be located near a power outlet or have long power cables to reach one). In a PoE system, a device that supplies power to other devices via PoE is called Power Sourcing Equipment (PSE), and the devices that receive power from the PSE are called Powered Devices (PDs). The PSE generally also acts as a network element, such as a switch or router. PDs can also be network elements (e.g., a wireless access point, a PoE repeater / hub, etc.) or network endpoints (e.g., a security camera, an Internet of Things (IoT) device, etc.).) or any other electronic device with a PoE port.

[0002] In a PoE system, the total power that the PSE can deliver at a given time ("available power") may be less than the total power that all connected PDs are consuming or intend to consume at that time ("power demand"). A power demand that exceeds the available power of a PSE can be referred to as a "PSE power disturbance." A PSE power disturbance can occur for a variety of reasons. For example, the PSE may be designed such that the maximum total power it can deliver is less than the sum of the maximum output power per port. For example, if...If a hypothetical PSE has a maximum total output power of 80 W and six ports, each capable of delivering a maximum output power of 20 W, then the sum of the maximum output power per port (6 × 20 W = 120 W) exceeds the available power (80 W). In such examples, if all ports of the PSE are connected to PDs that consume the full maximum power per port, then the power demand at that time exceeds the available power. Another example: Even if the PSE is designed so that the maximum total output power equals or exceeds the sum of the maximum output power per port, the actual available power at a given time may fall below the maximum available power, for example, due to a power outage of the PSE or other fault events.

[0003] US 2007 / 0135086A1 describes a power-hungry device (PD) configured to receive power over a communication link, such as an Ethernet connection, and which has a power interface controller for implementing a power supply protocol. The power interface controller captures several pieces of PD information representing various properties of the PD in order to transmit the PD information to a power supply device.

[0004] DE 11 2011 105 767 T5 describes a test device for connection to a power supply unit, the test device comprising: a network connector for connection to the power supply unit, which can provide power and communications to the test device; an auxiliary power source, which can provide power to the test device; a power selection module for setting a power level based on a user input, wherein several non-zero power levels can be set by the power selection module based on different user inputs, and wherein the test device is adjustable to emulate a consumer device associated with a particular class; a power negotiation module for negotiating the power from the power supply unit, which is connected via the network connector, based on the power level set by the power selection module;and an error message to indicate that the negotiation has failed. SHORT DESCRIPTION

[0005] A Power-over-Ethernet (PoE) power supply device (PSE) according to claims 1 to 12, a Power-over-Ethernet (PoE) powered device (PD) according to claims 13 to 18 and a system according to claims 19 and 20 is disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The present disclosure can be understood from the following detailed description, either alone or together with the accompanying drawings. The drawings serve to further understand the present disclosure and are an integral part of the present description and are incorporated therein. The drawings illustrate one or more examples of the present teaching and, together with the description, explain certain principles and modes of operation. In the drawings: Fig. This is a block diagram showing an example of a PoE-PSE. Fig. This is a block diagram that illustrates an example of a PoE-PD. Fig. is a block diagram showing an example of a PoE system with a PSE and connected PDs. Fig. is a process flow diagram that represents a first example of a procedure that can be performed by a PoE PSE. Fig. is a process flow diagram that shows a second example procedure that can be performed by a PoE-PSE. Fig. is a process flow diagram showing a third example procedure that can be performed by a PoE-PSE. Fig. is a block diagram showing an example of a storage medium that stores instructions that can be executed by a processor of a PoE-PSE. Fig. is a block diagram showing an example of a storage medium that stores instructions that can be executed by a processor of a PoE PD. Fig. is a process flow diagram showing a fourth example procedure that can be performed by a PoE-PSE. DETAILED DESCRIPTION

[0007] In some PoE systems, a PSE assigns power priorities to the connected PDs. These power priorities determine which PDs receive priority power in the event of a PSE power failure. That is, if a PSE power failure occurs, the PSE selects a first group of PDs to continue receiving PoE power and a second group to stop receiving PoE power. The first group comprises PDs with higher power priorities, and the second group comprises PDs with lower power priorities compared to the other PDs. The PSE may attempt to maximize the number of PDs in the first group that continue receiving PoE power while keeping the power demand at or below the available capacity.For example, the PSE can select the n highest-priority PDs to continue receiving PoE power, where n is the largest number that results in power demand equal to or less than the available power. Equivalently, the PSE can identify the p lowest-priority PDs to discontinue PoE supply, where p is the lowest number that results in power demand equal to or less than the available power. Note that "highest" and "lowest" here are relative to the other PDs connected to the PSE, not the highest and lowest priorities in an absolute sense. If there are more highest-priority PDs than can be included in the first group (for example, if including all highest-priority PDs would exceed the available power), then one or more highest-priority PDs will be excluded from the first group.Conversely, if additional performance headroom is available after adding all PDs with the highest priority in the first group, the PSE can consider the next higher priority level and continue selecting PDs with that priority, and so on at each level of performance priority in descending order, until the number of PDs selected for the first group is maximized while remaining at or below the available performance. If the PSE must choose between two PDs with the same performance priority, it can select one of the two PDs using any procedure, such as random selection or based on some other criterion.The power priority of a particular PD does not guarantee the inclusion or exclusion of the PD from the first group that continues to receive PoE power, but a higher power priority makes it more likely that a PD will be included in the first group that continues to receive PoE power, and also ensures that no PD with a lower priority is selected before the PD with a higher priority.

[0008] In many PoE systems, the power priorities of the PDs are determined based on self-reporting by the PDs themselves; that is, the PDs inform the PSE what priority they should have, and the PSE sets the power priorities to the values ​​specified by the PDs. The PDs can be configured, for example, during manufacturing and / or later by a user, to request a specific power priority from the PSE. PDs considered important or mission-critical can be programmed to request a high power priority (to increase the likelihood of remaining powered on in the event of a PSE power failure), and PDs whose downtime is more easily tolerated can be programmed to request lower power priorities.

[0009] In some cases, however, assigning power priorities according to the approach described above may not result in an optimal distribution of power to the PDs. Specifically, some PDs may have access to alternative power sources in addition to the power supplied via PoE from the PSE. Such alternative power sources could include, for example, a battery backup, a local power supply (such as a plug or adapter connected to the mains), a secondary connection to another PSE, or other power sources. If a PD has access to such an alternative power source, an interruption of the PoE power supply from the PSE to the PD would not necessarily cause the PD to fail, as the PD would be able to rely on its alternative power source (at least for a period of time).Such a PD therefore does not necessarily need a high power priority to ensure it remains powered on during a PSE power outage. Assigning a high power priority to such a PD can be inefficient, as it may result in another PD that requires PoE power to operate not receiving that power during a PSE power outage.

[0010] The examples disclosed here address the aforementioned problems by, among other things, configuring the PSE to adjust a PD's power priority when that PD has access to an alternative power source. Specifically, this is achieved by lowering the PD's power priority below the value it would otherwise have been assigned under a standard power priority assignment scheme (standard here refers to a power priority assignment scheme used by the PSE without regard to alternative power sources, such as assigning any power priority to PDs that request it as described above). For example, a PD that would have been assigned a HIGH power priority under a standard power priority assignment scheme might instead be assigned an adjusted power priority of MEDIUM or LOW if the PD has access to an alternative power source.Reducing the power priority of a PD with an alternate power source can allow more PDs to remain powered on during a PSE power failure than would otherwise be possible. This increase in the number of PDs that can stay powered during a PSE failure is achieved by removing the PD with the alternate power source from the group of PDs that continue to receive PoE power (since its priority has been lowered), which in turn frees up space for the addition of another PD that would otherwise have lost PoE power. Although the PD with the alternate power source is excluded from the group receiving PoE power, it is not powered down because it has the alternate power source. Thus, while the number of PDs receiving PoE power remains unchanged, the total number of PDs that can remain powered on is increased.

[0011] Consider, for example, a hypothetical scenario where a PSE has 60 W of available power and four PDs, each consuming 20 W, are connected to the PSE. The first three PDs (PD1, PD2, and PD3) have a HIGH power priority, and a fourth PD (PD4) has a MEDIUM power priority. This situation represents a PSE power failure because the available power (60 W) exceeds the power demand (4 × 20 W = 80 W). The PSE may therefore need to cut the PoE supply to one of the PDs to reduce the power demand to the level of the available power. In previous approaches, the PSE would select the three highest-priority PDs (PD1, PD2, and PD3) to continue receiving PoE power and would therefore cut the PoE power supply to PD4. According to the previous approach, a total of three PDs would remain switched on and one PD (PD4) would have to be switched off.However, assuming PD1 has an alternative power source, its power priority can be reduced to MEDIUM in the examples described here. As a result of this priority change, the PSE can now select PD2, PD3, and PD4 to continue receiving PoE power, while PD1 no longer receives PoE power (note that in this case, PD1 and PD4 both have the same priority, so the PSE can choose one of them). Therefore, in this scenario, all four PDs can remain powered, with PD2, PD3, and PD4 receiving PoE power and PD1 powered via its alternative power source.Although the total amount of energy available at the PSE is the same and the number of PDs selected to continue receiving PoE power is the same in both of the above cases, the total number of PDs that can continue to be powered is greater in the latter case because the power priority of the PDs has been adjusted to the alternative power source.

[0012] Previously, PSEs generally did not know whether a PD had an alternate power source. Accordingly, in the examples disclosed here, PDs can be configured to transmit this information to the PSEs, and the PSEs can be configured to listen for this information and then adjust their power priorities as described above. Some examples use link-level discovery protocol communication to indicate whether a PD has an alternate power source. Examples of link-level protocols include the Link Layer Discovery Protocol (LLDP) and other similar protocols. Specifically, some examples define a new data field within a standardized link-level discovery protocol communication structure to indicate whether the PD has an alternate power source, e.g.,A new Type-Length-Value (TLV) field in an Ethernet frame of LLDP communication. This new data field can be referred to here as the Alt_Pwr field. In the examples disclosed here, a PD can be configured to include the Alt_Pwr field in its link-layer protocol communication, and a PSE can be configured to monitor for such Alt_Pwr fields in the received link-layer protocol communication.

[0013] In some examples, in addition to indicating whether or not a PD has an alternative power source, the Alt_Pwr field may also contain information about the alternative power source (if one exists), such as the type of power source (e.g., battery, local power supply, etc.) and / or the amount of available power or its state of charge. In some examples, the PSE may be configured to consider this additional information when determining a PD's power priorities. For example, the PSE may determine whether the alternative power source is sufficient, and if not, it may refrain from reducing the PD's power priority. In some examples, an alternative power source may be considered adequate if its type belongs to a predetermined list of power sources, such as a local power supply (e.g., an AC adapter) connected to the electrical grid.Another example: A battery-like power source can be classified as suitable if its state of charge is above a predetermined threshold, and as unsuitable if its state of charge is below this threshold.

[0014] In some examples, the PSE can not only adjust the power priority of certain PDs based on whether they have alternative power sources (as indicated by the Alt_Pwr field in communications received from those PDs), but the PSE can also consider the presence of an alternative power source when selecting PDs to continue receiving PoE power during a PSE power outage. However, if two or more PDs have the same priority and the PSE must choose between them, the PSE can be configured to prioritize the PDs that do not have an alternative power source. Furthermore, in some examples, upon receiving a message from a PD indicating that it has an alternative power source, the PSE can proactively negotiate with the PD to discontinue its PoE power supply without necessarily waiting for a power outage to occur.

[0015] Furthermore, in some examples, the PSE can occasionally review and modify assigned power priorities, such as resetting a PD with a customized power priority to a default power priority. For instance, PDs can periodically send updated information about their alternate power sources via additional link-layer discovery protocol communication (over the Alt-Pwr field), and in response to a change in the status of an alternate power source for a PD, the PSE can modify the PD's power priority. For example, if a battery's state of charge falls below a threshold, the PSE can reset the PD's power priority to the default value. Other events detected through other means can also trigger the power priority review and resetting to default values.

[0016] The illustrations describe various devices, systems, and procedures that correspond to the aspects of the present disclosure.

[0017] Fig. This is a block diagram that conceptually represents a PSE for use in a PoE system in the form of the PSE 110. It should be understood that Fig. It is not intended to accurately or to scale represent specific shapes, dimensions, or other structural details, and implementations of PSE 110 may have a different number and arrangement of the components shown and may also include other parts that are not shown.

[0018] As in Fig. As shown, the PSE 110 comprises a switching hardware 120, a power supply 130, a variety of PoE ports 140 (“Ports 140”) and a control circuit 150.

[0019] The switching hardware 120 comprises circuitry that can selectively connect the ports 140 to each other and to one or more other ports (not shown), such as an uplink port, to enable the forwarding of data packets between the various devices connected to the PSE 110, as well as other associated components that participate in, control, or otherwise facilitate the communication of the data packets. The switching hardware of a PSE is known to those skilled in the art, so the switching hardware 120 will not be described in detail here.

[0020] The power supply 130 provides electrical power to the PSE 110, including power to operate the functions of the PSE 110 itself and the PoE power to be delivered by the PSE 110 to the connected PDs via the ports 140. The power supply 130 can be controlled by the control circuit 150 to selectively deliver PoE power to the ports 140; in other words, the power supply 130 can interrupt the supply of PoE power to specific ports 140 at the instruction of the control circuit 150 when required (e.g., during a power outage of the PSE). The power supply 130 comprises one or more power supply devices configured to receive input power from a source, such as mains power or a power distribution unit, and convert that power into forms suitable for use by the PSE 110.The power supply devices of the power supply unit 130 may include an AC-to-DC converter, a DC-to-DC converter, protective devices (e.g., overcurrent protection, overvoltage protection, etc.), and / or other power supply components that are involved in, control, or otherwise facilitate the power supply of the PSE 110. The power supplies of a PSE are known to those skilled in the art, so the power supply unit 130 will not be described in detail here.

[0021] Ports 140 comprise PoE-enabled ports, which may include, for example, RJ45 jacks. Each port 140 is configured to accept one end of an Ethernet cable, which may include an RJ45 plug. Each port 140 is coupled to the control circuit 150 (e.g., via the switching hardware 120) and configured to transmit data between the control circuit 150 and a PD connected to port 140. Each port 140 is also coupled to the power supply 130 and configured to provide PoE power to the PD connected to port 140 from the power supply 130 (unless PoE power has been disabled for port 140 by the control circuit 150). Fig. Three ports (i.e., ports 140_1, 140_2, 140_N) are shown, but any number of ports 140 equal to or greater than two can be included in the PSE 110. The PoE ports are known to those skilled in the art, so ports 140 are not described in detail here.

[0022] The control circuit 150 comprises a circuit configured (e.g., programmed) to perform operations 156 and 158. The control circuit 150 includes a processor and a storage medium on which instructions can be stored that the processor can execute to cause operations 156 and 158 to be carried out, special hardware configured to perform operations 156 and 158, or a combination thereof. In examples where the control circuit 150 includes a processor, the processor may comprise one or more processing devices capable of executing machine-readable instructions, such as a processor, central processing unit (CPU), controller, microcontroller, system-on-a-chip (SoC), digital signal processor (DSP), graphics processing unit (GPU), or other processing resources.In examples where the control circuit 150 includes dedicated hardware in addition to or instead of the processor, the dedicated hardware can comprise any electronic device configured to perform specific operations, such as an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a complex programmable logic device (CPLD), discrete logic circuits, a hardware accelerator, a hardware encoder, etc. In some examples, the control circuit 150 can be configured to control other operations of the PSE 110 in addition to operations 156 and 158, such as controlling operations of the switching hardware 120, power supply operations 130, security / authentication operations, and / or other operations of the PSE 110. Such other operations of control circuits are known to those skilled in the art and are therefore not described in detail here.

[0023] Operation 156, for which control circuit 150 is configured, involves receiving Link-Layer Protocol communications from PDs connected to PSE 110 (via ports 140). These communications include an Alt_Pwr field indicating whether the sending PD has an alternative power source. Specifically, PSE 110 can be configured to listen for Link-Layer Protocol communications, and when one is received, PSE 110 can examine the Alt_Pwr field to determine whether the sending PD has an alternative power source (and, in some examples, to determine other information about the alternative power source). In some examples, the Link-Level Discovery Protocol is LLDP.In general, LLDP communication consists of an Ethernet frame, a communication structure comprising a series of data fields formatted and ordered according to the specifications of the LLDP protocol. These fields include address fields (e.g., destination address, source address), followed by a series of mandatory TLVs (e.g., a chassis ID TLV, a port ID TLV, etc.), and optionally, so-called optional TLVs. Preambles, end fields, and other encapsulation data may also be included. Some optional TLVs may be defined according to an industry standard, such as IEEE Std 802.1AB, while others may be so-called user-defined TLVs, which can be vendor-specific. In some examples, the Alt_Pwr field is a new optional TLV of an LLDP frame (which can be either a standards-defined optional TLV or a vendor-specific custom TLV).In other examples, the link-level discovery protocol is the Cisco Discovery Protocol (CDP), the Foundry Discovery Protocol (FDP), the Nortel Discovery Protocol (NDP), Link Layer Topology Discovery (LLTD), or other similar link-level discovery protocols. These other link-level discovery protocols also define communication data structures, such as the Ethernet frame described above, which include various data fields, like the TLVs described above, although the formatting, naming, and other details of the data structures may vary from one protocol to another. Regardless of the protocol used, the Alt_Pwr field can be inserted into the communication structure, either as a new field (if the protocol allows it) or by repurposing an existing field.

[0024] Operation 158, for which the control circuit 150 is configured, involves setting power priorities for the connected PDs based on whether they have alternative power sources, as indicated by the Alt_Pwr field of their link-layer protocol communication (as processed in Operation 156). The power priorities can be used by the control circuit 150, as described above, to determine which PDs should continue to receive PoE power via ports 140 in the event of a PSE power failure.

[0025] Power priorities can include any number of priority levels or stages equal to or greater than two. Furthermore, these priority stages can be designated in any desired manner. For simplicity, it is assumed here that the power priorities comprise three stages labeled HIGH, MEDIUM, or LOW (where HIGH is the highest priority and LOW is the lowest), but a person skilled in the art would understand that any other number of stages and any other desired scheme for designating the power priorities can be used, such as numerical values, alphanumeric values, color codes, etc. As used here, a "higher" priority (or similar terms) is one that makes the PD more likely to be selected for the group of PDs that continue to receive PoE power, and vice versa with respect to a "lower" priority.Note that this meaning of "high" and "low" does not necessarily have to do with "high" and "low" in a numerical sense - in some priority schemes, for example, the highest priority may be designated as 1, while in other priority schemes 1 would be the lowest priority, and in still other schemes priorities have no numerical value at all.

[0026] In some examples, setting power priorities for connected PDs involves first determining a default power priority for each PD and then determining adjusted priorities for those PDs that have alternative power sources, with the adjusted priorities being reductions from the default power priorities. PDs that do not have an alternative power source can be assigned their default power priorities. A "default power priority" is a power priority determined according to a standard power priority determination scheme, i.e., the scheme that PSE 110 would use to assign power priorities if alternative power sources were not considered.An example of a default power priority scheme that the PSE 110 can use is to allow PDs to request a specific power priority and assign a default power priority to those PDs that corresponds to the power priority requested by the PD. Another default power priority scheme might involve, for example, recognizing a PD type (e.g., from information transmitted in the Link Layer Discovery Protocol communication) and assigning default power priorities based on the PD types. For instance, the control circuit 150 can consult a specified (predefined and / or user-configurable) list of PD types with associated priorities to determine the default power priorities for the PDs; PDs of a type not included in the list can receive a power priority specified for unknown PD types.

[0027] The extent to which customized power priorities are reduced compared to standard power priorities can vary from one implementation to the next and, in some examples, may be a user-configurable parameter. In some examples, the customized power priorities of all PDs with an alternate power source (or, in some cases, all PDs with an alternate power source deemed appropriate, as described below) may be reduced by a fixed number of steps (e.g., one step in some examples) below their standard power priority. In other examples, the number of steps by which the customized priority is reduced compared to the standard priority may vary depending on one or more factors.The number of steps by which the adjusted priority is reduced from the default value can depend on the default priority level—if the default priority is higher, the number of reduced steps can be greater. In other examples, the amount by which the power priority of a given PD is reduced from its default priority can vary from one PD to the next, based on the PD's characteristics and / or the type of alternative power source it has. For example, the power priority of a PD with a more reliable power source, such as a grid-connected local power supply, can be reduced more than that of a PD with a less reliable power source, such as a battery backup.

[0028] In other examples, setting power priorities for connected PDs based on whether they have alternate power sources involves setting all PDs with an alternate power source to a specific (e.g., predefined or user-configurable) priority, which may be lower than the highest power priority. For example, all PDs with an alternate power source (or in some cases, an alternate power source deemed adequate, as described below) can be set to a LOW power priority. For other PDs that do not have an alternate power source (or have an inadequate one), power priorities can be set according to a standard power priority scheme, as described above.

[0029] In some examples, the process described above for adjusting the power priorities of PDs is performed in response to a PD connecting to the PSE 110. The PD may send initial link-layer discovery protocol communication as part of a discovery process, and this may trigger the performance priority assignment process for that PD. In other examples, the performance priority assignment process described above may be initiated in response to a different condition. That is, the default performance priorities may be used for all PDs until the specified condition is met, after which the performance priorities of some PDs may be adjusted as described above. For example, the performance priority assignment process may be initiated when the current power demand of the PSE 110 exceeds a predefined and / or user-configurable threshold, such as...85% of the available power. Therefore, if the first few PDs are connected to a PSE 110 and the power demand is below the threshold, the power priority adjustments described above can be suspended. Later, if more PDs are connected to the PSE 110 (or if the demand of the existing PDs increases) and the threshold is exceeded, the PSE 110 can adjust the priorities of the PDs that have alternative power sources, as described above.

[0030] Once the power priorities of the PDs have been assigned, the control circuit 150 of the PSE 110 can respond to power failure events as described above. That is, when a power failure event is detected (i.e., the power demand exceeds the available power), the control circuit 150 selects a first group of PDs that the PSE continues to supply with PoE power, and a second group of PDs that the PSE no longer supplies with PoE power. The first group comprises the PDs with higher power priorities, and the second group comprises the PDs with lower power priorities relative to the other PDs. The control circuit 150 can attempt to maximize the number of PDs in the first group that continue to receive PoE power while keeping the power demand at or below the available power.For example, the control circuit 150 can select the n highest-priority PDs to continue receiving PoE power, where n is the largest number that results in power demand equal to or less than the available power. Alternatively, the control circuit 150 can identify the lowest-priority PDs p to discontinue PoE power supply, where p is the lowest number that results in power demand equal to or less than the available power. If there are more highest-priority PDs than can be included in the first group (e.g., if including all PDs would exceed the available power), then one or more highest-priority PDs are excluded from the first group.Conversely, if additional power headroom is available after adding all PDs with the highest priority, the control circuit 150 can consider the next higher priority level and continue selecting PDs with that priority until the number of PDs in the first group is maximized while reaching or falling below the available power. If the control circuit 150 must choose between two PDs with the same power priority, it can select either PD using any selection method, for example, by preferentially selecting PDs that have no alternative power sources. To terminate PoE power to the PDs in the second group, the control circuit 150 can disable PoE power for the ports 140 connected to these PDs (note that data communication can still flow through these ports as if they were standard Ethernet ports).

[0031] In addition to the operations described above, in some examples the control circuit 150 of the PSE 110 may be configured to perform each of the operations described below with respect to procedures 400, 500, 600 and / or 900 of the Fig. Certain aspects of PSE 110 are discussed in Fig. explained in more detail, in which a PoE system is shown in which the PSE 110 can be used. Fig. will follow the description of Fig. described.

[0032] In Fig. A PD for use in a PoE system is described in the form of PD 200. Fig. This is a block diagram that conceptually represents the PD 200. It should be understood that... Fig. It is not intended to accurately or to scale represent specific shapes, dimensions, or other structural details, and implementations of the PD 200 may have a different number and arrangement of the components shown and may also include other parts that are not shown.

[0033] As in Fig. As shown, the PD 200 comprises a control circuit 270 and one or more terminals 271. The PD 200 can optionally also include an alternative power source 202. The PD 200 can be any PoE-enabled electronic device, such as network devices (e.g., wireless access points), IP phones, IP security cameras, laptops, computer monitors, kiosks, sensors, other IoT devices, or other PoE-enabled electronic devices.

[0034] Ports 271 comprise PoE-enabled ports that can include RJ45 jacks. Each port 271 is configured to accept one end of an Ethernet cable, which can include an RJ45 plug. This allows the PD 200 to connect to a PSE, such as the PSE 110 described above. Ports 271 are configured to receive PoE power and supply power to the other components of the PD 200. Ports 271 are also communicatively coupled to the control circuit 270 to transfer data between the control circuit 270 and another device (such as a PSE) connected to port 271. Fig. Two ports 271 are shown, but the PD 200 can contain any number of ports 271 equal to or greater than one. Some PDs 200 have only one port 271. Others may have two ports 271 so that the PD can be connected to multiple network devices (e.g., multiple PSEs) to provide redundancy, for example. The PD 200 could also have more than two ports 271. As mentioned earlier, PoE ports are familiar to those skilled in the art, so the ports 271 will not be described in detail here.

[0035] The control circuit 270 comprises a circuit configured (e.g., programmed) to perform operations 272 and 274. The control circuit 270 includes a processor and a memory medium that stores instructions which the processor can execute to cause operations 272 and 274 to be carried out, dedicated hardware configured to perform operations 272 and 274, or a combination of these elements. In this context, the processor and dedicated hardware can include any of the examples discussed above in relation to the control circuit 150. In some examples, the control circuit 270 can be configured to control additional operations of the PD 200 besides operations 272 and 274, e.g.,Operations that control the communication between the PD 200 and the PSE (which may be common to all PD 200 types), as well as other operations that may be more specific to the functions of the various PD 200 types. Since the PD 200 can be a large number of devices with very different functions, the other operations performed by the control circuit 270 may vary from one device to another. These other PD operations are known to those skilled in the art and are not described here.

[0036] Operation 272 involves determining whether the PD 200 has an alternate power source 202, or whether it is available. The alternate power source 202 is optional, and some instances of the PD 200 may have the alternate power source 202, while others do not. Regardless of whether the PD 200 has the alternate power source 202, it is configured to perform Operation 272 to check for its presence. As used here, the PD 200 has the alternate power source 202, or the alternate power source 202 is "present" or "available," if the alternate power source 202 is in a state capable of supplying power to the PD 200. This is in contrast to the mere presence of components that could potentially supply power but are currently unable to do so.For example, a PD 200 whose power cord is connected to the mains can determine that it is an existing / available alternative power source 202, but the PD 200 can determine that the power cord is not an alternative power source if the power cord is disconnected from any power source. The alternative power source 202 does not necessarily have to be currently supplying power to the PD 200 for the PD 200 to consider the alternative power source 202 as existing / available, but the power source should be in a state where it is energized and capable of supplying power when requested. Examples of alternative power sources are batteries (either integrated into the PD 200 or as an external unit connected to the PD 200), local power supplies (e.g., power cords, adapters, or chargers connected to a power source (e.g., a power outlet), or other power supplies (e.g., a power outlet).(connected to the mains power supply), a wireless charger, or any other external power source (other than the PoE power supply from the PSE). In some examples, if the PD 200 has two PoE connections to two different PSEs, the PD 200 may also determine that this constitutes an alternate power source 202 (i.e., one PSE would count as an alternate power source with respect to the other PSE and vice versa), as long as both connections are configured to supply PoE power to the PD 200; however, if one of the PSEs is configured to only supply data to the PD 200, the PD 200 may determine that it does not have an alternate power source 202.

[0037] The control circuit 270 can detect whether an alternative power source is available in several ways. For example, some PD 200s, due to their design, may not be able to have any alternative power source 202 other than multiple PoE ports (in examples where this can be considered an alternative power source). This might be the case, for instance, because the PD has no other power-drawing components besides the ports 271, such as a battery, power cord, power jacks, or similar. In such a PD, the control circuit 270 can be programmed (e.g., during manufacturing or configuration) to automatically detect that it has no alternative power source. Alternatively, in examples where PoE connections to multiple PSEs are considered an alternative power source, the control circuit 270 can be programmed to check this as well.Particularly in examples where PoE connections to multiple PSEs are considered as an alternative power source, the PD 200 can be alerted via PoE circuitry included within the PD 200 to manage the PoE ports 271. This PoE circuitry can be part of the control circuitry 270 or separate circuitry that the control circuitry 270 can communicate with to determine if multiple PoE connections are present. Other PD 200s that have one or more components that may provide an alternative power supply (e.g., a battery, an AC adapter, an AC outlet, a wireless charging circuit, etc.)A power management / budgeting circuit (not shown) may be provided to monitor and / or control the power supplied by these sources, and the control circuit 270 may be configured to query such a power management circuit to determine whether the alternative power source 202 is currently powered and capable of supplying power; if so, it is identified as an existing / available alternative power source 202, and if not, it is not identified as an existing / available alternative power source 202. Such power management and budgeting circuits are typically included in any PD that has power-receiving components (e.g., a battery, a power cord, etc.) to monitor and control the flow of power to or through these components and are known to those skilled in the art.Alternatively or additionally, the control circuit 270 can be configured to directly detect whether power is present from an alternative power source 202, for example, via a sensor (not shown), such as a current sensor connected to a system power bus or other power line that receives power from the alternative power source 202. Another example: A PD 200 that has a battery (or is configured to accommodate one) is also equipped with a battery charging / management circuit, and the control circuit 270 can query this battery charging / management circuit to determine whether the battery is installed and, if so, its state of charge.

[0038] Operation 274 involves sending a link-layer protocol communication to the PSE that includes an Alt_Pwr field indicating whether the PD has an alternative power source. In some examples, both PDs 200 that have an alternative power source 202 and PDs 200 that do not include the Alt_Pwr field in their link-layer protocol communication, with the PDs 200 that do not have an alternative power source 202 indicating this in the Alt_Pwr field. In other examples, a PD 200 that does not have an alternative power source 202 may omit or send an empty Alt_Pwr field to indicate that it does not have an alternative power source 202. In some examples, the Link-Level Discovery protocol is LLDP and the Alt_Pwr field is a TLV of an LLDP Ethernet frame that has been defined (either by a manufacturer or by a standard) to indicate whether the PD has an alternative power source.In other examples, the link-level discovery protocol is CDP, Foundry Discovery Protocol (FDP), Nortel Discovery Protocol (NDP), Link Layer Topology Discovery (LLTD), or other similar link-layer discovery protocols, and in each of these examples, the Alt_Pwr field can include a new field added to a message from one of these protocols. In some examples, the link-layer protocol communication sent by the PD 200 might be communication sent by the PD 200 during a discovery operation, such as when the PD 200 is first connected to the PSE (or when communication is resumed after a failure) and the PD 200 identifies itself to the PSE. Link-layer protocol communication can serve multiple purposes, such as providing discovery information about the PD 200 to the PSE in addition to providing the information contained in the Alt_Pwr field.Link-layer protocol communication can be sent more than once. For example, it can be sent during the initial connection of the PD 200 to the PSE 110 and / or regularly at specified intervals thereafter. Furthermore, in some scenarios, the PD 200 can send a message in response to the detection of a specific condition, such as a change in the status of its alternate power source.

[0039] In some examples, the control circuit 270 can also include information in the Alt_Pwr field that identifies the type of alternative power source. In some examples, if the alternative power source is a battery, the control circuit 270 can also include information about the battery's state of charge in the Alt_Pwr field, such as the charge level, the estimated battery runtime, or other information about the charge stored in the battery.

[0040] In Fig. A PoE system is described in the form of System 100. System 100 comprises the PSE 110 described above. System 100 also includes several different instances of the PD 200 described above. Some aspects of the PSE 110 and the PDs 200 described above are in Fig. not shown. Furthermore, descriptions of certain items may be missing. Fig. aspects presented, which were already mentioned above in relation to the Fig. The sections described below can be omitted.

[0041] As in Fig. As shown, the PDs 200 are coupled with the PSE 110. In Fig. Three PDs 200 are shown, labeled PD_1, PD_2, and PD_N. It is understood, however, that any number from 1 to N of PDs 200 can be connected to the PSE 110, where N is the number of ports 140 of the PSE 110 (N is equal to or greater than 2). The PDs 200 are connected to the PSE 110 via corresponding Ethernet cables 210, which are plugged into ports 140 of the PSE 110 and ports 271 of the PDs 200.

[0042] As in Fig. As shown, each PD 200 sends a Link Layer Protocol communication 160 to the PSE 110 (e.g., as part of a discovery process). The PD 200 designated PD_1 sends message 160_1, PD_2 sends message 160_2, and so on up to PD_N, which sends message 160_N. Each of the messages 160 includes a set of fields as defined by the Link Layer Discover Protocol, including an Alt_Pwr field 161. Fig. The messages 160, for example, are displayed as comprising a destination address field (labeled DST in the figure), a source address field (labeled SRC in the figure), and the Alt_Pwr field 161. It is understood that the communication may include several other fields, which are not shown here for the sake of clarity. The Alt_Pwr fields 161 indicate whether the respective PD 200 that sent the message has an alternative power source 202. In the example of Fig. The PDs 200 designated PD_1 and PD_2 have alternative power sources 202 (in the form of a battery and a power supply, respectively), and therefore the Alt_Pwr fields 161 in communications 160_1 and 160_2 indicate "Yes" (i.e., that an alternative power source 202 is present). The PD 200 designated PD_N, on the other hand, does not have an alternative power source, so the Alt_Pwr field 161 in communication 160_N indicates "None". The values ​​of the messages 160 are represented as words in the figure (e.g., "Yes" or "None") for ease of understanding, but in practice, the actual values ​​may be encoded in a machine-readable format, such as binary. Furthermore, in some examples, the Alt_Pwr field 161 may convey information about the power source 202, if present, such as... B. the type of power source and the state of charge (in the case of a battery).In some examples, message 160_1 can also indicate that the power source 202 of PD_1 is a battery, as well as its state of charge (in . Fig. This is given as the time period in which the PD can be operated, but it could also be given in other terms, such as raw charge quantity (watt-hours), percentage of the total charge, etc.), and message 160_2 may also indicate that the power source 202 of PD_2 is a local power supply connected to the mains (e.g. via a mains adapter).

[0043] The PSE 110 receives the messages 160 and can determine the power priority based on the Alt_Pwr fields 161. As shown in Table 151, the control circuit 150 can, for example, record which PDs 200 have alternative power sources 202, as specified in the Alt_Pwr fields 161 of the messages 160. The control circuit 150 knows which messages 160 originate from which PDs 200 based on the respective ports 140 where the messages were received and / or based on the SRC field (in examples where such a field is provided in the message 160). The control circuit 150 can also determine default power priorities for each of the PDs, as described above. Hypothetical values ​​of the default power priorities for the PDs 200 are shown in Table 151.Based on the standard power priorities and whether the PDs 200 have alternative power sources 202, the control circuit 150 can determine assigned priorities for the PDs 200. The assigned power priorities can be adjusted (e.g., reduced) relative to the standard power priorities for those PDs 200 that have alternative power sources 202, as described above. In the section on... Fig. In the example shown, the adjusted power priorities of the PDs 200, which have alternative power sources 202, are reduced by one step compared to the standard power priority of the PDs 200. Since the PDs 200 designated PD_1 and PD_2 have alternative power sources 202, the control circuit 150 can reduce their power priorities such that PD_1 is assigned a LOW power priority (downgraded from its standard MEDIUM power priority) and PD_2 is assigned a MEDIUM power priority (downgraded from its standard HIGH power priority), as shown in Table 151. However, since PD_N does not have an alternative power source 202, its assigned power priority remains the same as the standard power priority, in this case HIGH. (The term “adjusted performance priority” used here refers to an assigned performance priority that has been adjusted relative to a standard performance priority).In some examples, the control circuit 150 can store some or all of the information described above in a data structure such as Table 151. In other examples, the control circuit 150 can determine or use the information as needed and store some or all of it, but not necessarily all in the same data structure or format as in Table 151. In some examples, additional information can also be stored, such as the type of power source, the state of charge, etc.

[0044] In some scenarios, the system can maintain a record of the default power priorities for all PDs, including those whose power priority has been adjusted. The PSE 110 may occasionally review the power priority assignments and decide that the power priority of a particular PD 200 should be reset to the default value. Recording the default power priorities for all PD 200s can facilitate such a power priority reset. For example, the power priorities might need to be reset in response to an event that affects the ability of the alternate power source to supply power to the PD 200.Such events might include, for example, the battery charge level falling below a threshold, the power output of a secondary PoE connection to another PSE being reduced, a local power supply being disconnected or failing, or other similar events that could affect the ability of the alternative power source to provide power. These events can be communicated to the PSE 110 via the Alt_Pwr field of link-layer protocol communications. For example, link-layer protocol communications can be sent periodically from the PDs 200 to the PSE 110, and the PDs 220 can include status updates regarding their alternative power sources in these communications.

[0045] With further reference to Fig. Let's assume a power failure occurred and the PSE 110 was only able to supply power to a subset of the PDs 200. In this case, the PSE 110's control circuit 150 can select a subset of the PDs 200 with the highest priority to continue receiving PoE power and discontinue PoE power supply to the remaining PDs 200. Since the assigned priorities of PD_1 and PD_2 have been reduced, they are less likely to be selected to continue receiving PoE power, whereas PD_N is more likely to be selected to receive PoE power.

[0046] For example, assuming only PD_1, PD_2, and PD_N are present, and only one PD 200 can be powered via PoE, PD_N would be selected to continue receiving PoE power because it has the highest priority (HIGH) of the three connected PD 200s. Thus, all three PD 200s remain powered on, with PD_N receiving PoE power and PD_1 and PD_2 powered by their alternative PD 202 power sources. However, if the same scenario is considered without adjusting the power priorities, there is a risk that PD_2 will be selected to receive PoE power instead of PD_N (since both PD_2 and PD_N have the default power priority of HIGH), and in this case, PD_N would be powered off.By adjusting the power priorities of the PDs 200 that have alternative power sources 202, the number of PDs 200 that can remain switched on during a PSE power outage can be increased compared to a scenario in which the power priorities were left at their default values.

[0047] In the Fig. Example procedures 400, 500, 600, and 900 are described. Methods 400, 500, 600, and 900 can be performed, for example, by a PSE such as the PSE 110 described above. Specifically, in some examples, methods 400, 500, 600, and / or 900 can be performed by the control circuit 150 of the PSE 110. In some examples, the control circuit 150 includes a computer-readable storage medium that stores instructions corresponding to the operations of procedures 400, 500, and / or 600; that is, instructions configured to cause the PSE 110 to execute procedures 400, 500, 600, and / or 900 when executed by a processor of the control circuit 150. In some examples, the control circuit 150 includes special hardware configured to perform procedures 400, 500, 600 and / or 900.In some examples, the control circuit 150 is configured to execute procedures 400, 500, 600 and / or 900 through a combination of a processor that executes instructions and dedicated hardware.

[0048] As in Fig. As shown, procedure 400 comprises the operations of blocks 402, 404, 406, 408 and 410, which are described in more detail below.

[0049] In block 402, the PSE determines default power priorities for each of the connected PDs. These default power priorities are the power priorities that would be assigned to each PD using a standard power priority assignment scheme, such as assigning each PD the power priority requested by that PD. The default power priorities are the same as the power priorities that would be assigned to each PD if alternative power sources were disregarded; that is, if it were assumed that each PD had no alternative power source. Although shown first for simplicity, block 402 does not necessarily execute first; for example, block 402 may execute before or concurrently with block 408 at any time.

[0050] In block 404, the PSE receives link-layer protocol communication with an Alt_Pwr field from a connected PD. In some examples, the communication received in block 404 might be part of a discovery process performed when a PD first connects to the PSE (or reconnects after an interruption or error event). In other examples, the message received in block 404 might be a subsequent message; for instance, PDs might periodically send messages to the PSE via the link-layer discovery protocol, and block 404 might include one such message.

[0051] In block 406, the PSE determines whether the Alt_Pwr field indicates that the PD sending the message has an alternative power source. If the Alt_Pwr field indicates that the PD has a power source (determination in block 406 = Yes), the procedure continues with block 408. If the Alt_Pwr field indicates that the PD does not have a power source (determination in block 406 = No), the procedure continues with block 410.

[0052] In block 408, the PSE reduces the power priority of the PD relative to the standard power priority set in block 402. In other words, the PSE determines an adjusted priority for the PD that is lower than the standard priority and assigns this adjusted priority as the power priority for the PD.

[0053] In block 410, the PSE uses the standard priority determined in block 402 as the performance priority for the PD. In other words, the assigned performance priority for the PD is the same as the standard performance priority.

[0054] In some examples, blocks 404 to 410 can be repeated for each PD connected to the PSE until all PDs have been assigned power priorities.

[0055] In some examples, blocks 406 and / or 408 can be executed immediately after block 404. In other examples, the PSE can wait to execute blocks 406 and / or 408 after block 404 has completed until another condition is met. In some implementations, this condition might be, for example, that the system's current power demand exceeds (or equals) a certain threshold (which may be predefined or user-configurable). In implementations where blocks 406 and / or 408 are delayed until another condition is met, the PDs can be assigned their default power priorities, as defined in block 402, in the meantime. When blocks 406 and 408 are finally executed, the power priorities defined in these blocks can override the originally assigned power priorities.

[0056] As in Fig. As shown, procedure 500 includes the operations of blocks 502, 504, 506, 507, 508, and 510. The procedure may optionally also include the operations of block 514. Procedure 500 is a modification of procedure 400. Specifically, the operations of blocks 502, 504, 506, 508, and 510 may be similar to the operations of blocks 402, 404, 406, 408, and 410 described above, but procedure 500 differs from procedure 400 by adding block 507 between blocks 506 and 508 and (optionally) adding block 514 after block 508.

[0057] In block 502, the PSE determines the default power priorities for each of the connected PDs. Although shown first for simplicity, block 502 is not necessarily executed first; for example, block 502 may be executed before or at the same time as block 508.

[0058] In block 504, the PSE receives link-layer protocol communication with an Alt_Pwr field from a connected PD. As mentioned above, this communication can be part of an initial discovery process or subsequent communication.

[0059] In block 506, the PSE determines whether the Alt_Pwr field indicates that the PD sending the message has an alternative power source. If the Alt_Pwr field indicates that the PD has a power source (determination in block 506 = Yes), the procedure continues with block 512. If the Alt_Pwr field indicates that the PD does not have a power source (determination in block 506 = No), then the procedure continues with block 510.

[0060] In Block 507, the PSE determines whether the PD's alternative power source, as specified in the Alt_Pwr field, is appropriate. In some examples, determining whether the alternative power source is appropriate includes determining the type of alternative power source. Specifically, in these examples, the Alt_Pwr field may indicate not only whether the PD has an alternative power source, but also the type of alternative power source. In some examples, the Alt_Pwr field may indicate the following types of alternative power sources: battery, a local power supply connected to an external power source (such as mains power) via a power cord, AC adapter, or similar device, and another PoE connection to a different PSE (other than the PSE performing Procedure 500).In some examples, the types of power sources could be specified with even greater granularity than mentioned above; for instance, different subtypes of local power supplies could be identified as distinct types, such as power cords, adapters, wireless chargers, etc. In some examples, once the PSE knows the type of alternative power source, it can determine its suitability based on that type, for example, by consulting a specific (predefined and / or user-configurable) list of alternative power source types considered suitable.

[0061] In some examples, in addition to determining the type of alternative energy source, or instead of determining whether the alternative energy source is adequate, the determination of whether the amount of energy supplied by the energy source is sufficient may be included. In such examples, the Alt_Pwr field may specify the amount of energy supplied by the alternative energy source. The supplied amount of energy may be compared to a predetermined threshold, and the alternative energy source may be adequate if the supplied amount of energy exceeds the threshold. The threshold may be a general threshold that is the same for all PDs (e.g.,(equal to a maximum output power per PSE port or another predefined or user-configurable value), or the threshold can vary from one PD to the next based on their power requirements, which the PDs can report to the PSE during or after the assessment. In some examples, certain types of alternative power sources may be assumed to be sufficient, such as a mains power connection, so that in such cases, reporting the amount of power supplied can be omitted, while types of power sources that are sometimes sufficient and sometimes not, such as another PoE port, may go through the procedure described above of comparing the amount of power supplied to the threshold. An example of how to determine whether the alternative power source is adequate is given below with reference to [reference to relevant section]. Fig. described in more detail.

[0062] If the alternative energy source is suitable (Block 507 determination = Yes), the procedure continues with Block 508. If the alternative energy source is not suitable (Block 507 determination = No), the procedure continues with Block 510.

[0063] In block 508, the PSE lowers the power priority of the PD compared to the standard power priority set in block 502.

[0064] In block 510, the PSE uses the default priority specified in block 502 as the performance priority for the PD.

[0065] In some examples, blocks 504 to 510 can be repeated for each PD connected to the PSE until all PDs have been assigned power priorities.

[0066] In some examples, procedure 500 optionally includes the additional operations of block 514. In block 514, the PSE can begin negotiations with the PD to terminate the PD's PoE power supply. This can be a proactive disabling of the PD's PoE power supply, independent of a PSE power fault event. This can potentially prevent a PSE power fault from occurring in the first place, rather than waiting for one to happen and then reacting to it. In some examples, the PSE simply requests the PD to accept the interruption of the PoE power supply, but the PD can refuse this request (as opposed to a PSE fault event, where the PSE itself decides which PDs continue to receive PoE power and which are shut down).In some examples, the negotiation of block 514 may be performed in response to the fact that the type of alternative power source belongs to a list of specific power sources (for example, the same list of power sources mentioned above in block 507, or a different list). In other words, in some examples, such negotiations are performed only for PDs that have certain types of alternative power sources. In other examples, the negotiations may be performed for any PD that was determined in block 506 to have a suitable power source. In still other examples, block 514 is omitted. In some examples, block 514 is executed after block 508, as shown; however, in other examples, block 514 may be executed between blocks 507 and 508, or concurrently with block 508.

[0067] As mentioned above in relation to blocks 406 and 408 of procedure 400, blocks 506-514 may in some examples be executed directly in response to block 504 without waiting for another condition to be met, or in other examples the execution of some or all of these blocks 506-514 may be delayed until another condition is met (such as the power requirement exceeding a threshold).

[0068] As in Fig. As shown, Procedure 600 comprises the operations of Blocks 602, 604, 606, 608, 610 and 612. Procedure 600 can be used in Block 507 of Procedure 500 as an example of how to determine whether the alternative energy source is appropriate.

[0069] In block 602, the PSE determines the type of alternative power source specified in the Alt_Pwr field.

[0070] In block 604, the PSE determines whether the alternative power source is a battery. If the alternative power source is a battery (determination in block 604 = Yes), the procedure continues with block 606. If the alternative power source is not a battery (determination in block 604 = No), the procedure continues with block 610.

[0071] In block 606, the PSE determines whether the battery's state of charge, as specified in the Alt_Pwr field, meets a threshold (e.g., exceeds the threshold in some examples, or reaches / exceeds the threshold in others). The state of charge can be specified as a raw charge quantity (e.g., watt-hours), as a percentage of full charge, as the estimated runtime of the PD on the battery, or as any other suitable metric for measuring or characterizing the charge quantity in the battery. The threshold can be a predefined value, a user-configurable value, or both (e.g., the threshold can initially be a predefined value that the user can then change). If the state of charge meets the threshold (determination in block 606 = Yes), the procedure continues to block 608. If the state of charge does not meet the threshold (determination in block 606 = No), the procedure continues to block 612.

[0072] In block 608, the PSE identifies the alternative power source as appropriate.

[0073] In Block 610, the PSE determines whether the type of alternative power source, as specified in the Alt_Pwr field, is included in a list of approved alternative power sources. The list of approved power sources may include, for example, power source types considered reliable and / or capable of fully powering the PD, such as a local power supply connected to the mains (e.g., via a power cord, adapter, wireless charger, etc.). The list of approved power sources may be predefined (e.g., specified by a manufacturer) and / or user-configurable. If the type of alternative power source is found in the list (Determination in Block 610 = Yes), the procedure proceeds to Block 608. If the type of alternative power source is not found in the list (Determination in Block 610 = No), the procedure proceeds to Block 612.

[0074] In block 608, the PSE identifies the alternative power source as insufficient.

[0075] Procedure 600 identifies as suitable: (a) batteries with a sufficient state of charge (blocks 604→606→608), or (b) other types of power sources included in the approved list of power sources (blocks 604→610→608). On the other hand, Procedure 600 identifies as unsuitable: (c) batteries with an insufficient state of charge (blocks 604→606→612), or (d) other types of power sources not included in the approved list (blocks 604→610→612).

[0076] In Fig. An example of a non-transitory, computer-readable storage medium 700 (storage medium 700) is now described. The storage medium 700 stores instructions 756 and 758, which can be executed by a processor of a PSE (e.g., a processor of the control circuit 150 of the PSE 110) to cause the PSE to perform various operations described herein. In some examples, the storage medium 700 is part of a PSE, such as the PSE 110. In some embodiments, for example, the storage medium 700 is part of the control circuit 150, and the control circuit 150 further comprises a processor that is coupled to the storage medium 700 and configured to read and execute instructions 756 and 758. In some embodiments, the storage medium 700 can be provided as a computer program product that is at least initially separate from a PSE.The computer program product can be used to program a PSE to perform operations associated with instructions 756 and 758, for example by transferring instructions 756 and 758 from the storage medium 700 to the PSE, either for copying into the local memory of the PSE or for immediate execution by the PSE.

[0077] Instructions 756 include instructions for monitoring the link-layer protocol communication of connected PDs with an Alt_Pwr field indicating whether a PD has an alternate power source. For example, instructions 756 may include instructions for performing operations 156 and other related operations described above in relation to PSE 110. Instructions 756 may also include operations described above in relation to blocks 404 and 504 of procedures 400 and 500.

[0078] Instructions 758 include instructions for setting power priorities for the connected PDs, depending on whether they have alternative power sources, as specified in the Alt_Pwr field. For example, instructions 758 may include commands to perform operations 158 and other related operations described above in relation to the PSE 110. Instructions 758 may also include operations described above in relation to blocks 402, 406, 408, and 410 of Procedure 400, blocks 502, 506, 507, 508, and 510 of Procedure 500, and / or blocks 602 through 612 of Procedure 600.

[0079] In Fig. An example of a nontransitory computer-readable storage medium 800 (Storage Medium 800) is now described. Instructions 872 and 874 are stored on the Storage Medium 800 and can be executed by a processor of a PD (e.g., a processor of the control circuit 270 of the PD 200) to cause the PD to perform various operations described herein. In some examples, the Storage Medium 800 is part of a PD, such as the PD 200. In some implementations, for example, the Storage Medium 800 is part of the control circuit 270, and the control circuit 270 also includes a processor that is coupled to the Storage Medium 800 and configured to read and execute instructions 872 and 874. In some implementations, the Storage Medium 800 can be provided as a computer program product that is at least initially separate from a PD.The computer program product can be used to program a PD to perform operations associated with instructions 872 and 874, for example by transferring instructions 872 and 874 from the storage medium 800 to the PD to copy them into the PD's local memory or to have them executed immediately by the PD.

[0080] Instructions 872 include instructions for determining whether the PD has an alternative power source. Commands 872 may include commands for performing the operations described above in 272 and other related operations with respect to the PD 200.

[0081] Instructions 874 include instructions for sending a link-layer protocol communication containing an alternate power field indicating whether the PD has an alternate power source. Instructions 874 may include commands to perform the operations described above in 274 and other related operations with respect to the PD 200.

[0082] As in Fig. As shown, the procedure comprises 900 operations of blocks 902, 904 and 906.

[0083] In block 902, the PSE sets the power priorities for the connected PDs, including determining the default power priorities for each PD and also the customized power priorities for PDs that have alternative power sources, according to one of the approaches described above (e.g., by executing procedure 400 or 600). The PSE can store the default power priorities of all PDs, including those PDs to which customized power priorities have been assigned.

[0084] In Block 904, the PSE detects a change of state in the system. In some implementations, the change of state may be a change that affects the alternative power source of one or more PDs. In some implementations, the change of state includes, for example, a deterioration in the ability of a particular PD's alternative power source to adequately power the PD. In some implementations, such a change of state may consist of the state of charge of a battery falling below a minimum threshold (which may be predetermined or user-configurable and may be the same as or different from the threshold mentioned in Block 606 of Procedure 600), the rate of discharge of a battery exceeding another threshold, and / or another battery fault condition occurring (e.g.,(that the battery temperature exceeds a certain operating range, that the battery is no longer plugged in or otherwise unable to supply power, etc.). In some embodiments, such a change of state may consist of a local power supply being unable to supply power (e.g., because the plug has been pulled out or another fault has occurred), or that the amount of power supplied by the local power supply is reduced. In some implementations, such a change of state may consist of a secondary PoE connection to another PSE no longer supplying power or that the amount of power supplied is reduced.Such changes in the state of the PDs' alternative power sources can be communicated to the PSE, for example, via the Alt_Pwr fields of the Link Layer Discovery protocol communication, which the PDs can send periodically and / or in response to events detected by the PD. In other examples, the system state change might be another type of system state change. For instance, an administrator might put the PSE into a specific mode, which would then be considered a state change.

[0085] In Block 906, in response to the detection in Block 904, the network operator can reset the power priority of one or more PDs that were previously assigned a customized power priority in Block 902 to their respective default power priorities. If the state change detected in Block 904 is a deterioration in the ability of an alternative power source to supply power to a PD, in some examples the power priorities of only the PD (or PDs) affected by the state change are reset to default, while the other PDs retain their customized power priorities. In other examples, the power priorities of all PDs can be reset to their default priorities.

[0086] The above description covers various types of electronic circuits. The term "electronic" as used here is broad and encompasses all types of circuits that utilize electricity, including digital and analog circuits, direct current (DC) and alternating current (AC) circuits, as well as circuits for converting electricity into another form of energy and circuits for using electricity to perform other functions. In other words, no distinction is made here between "electronic" circuits and "electrical" circuits.

[0087] It is understood that both the general description and the detailed description contain examples that are explanatory and intended to aid in understanding the present disclosure without limiting its scope. Various mechanical, compositional, structural, electronic, and operational modifications may be made without deviating from the scope of this description and the claims. In some cases, known circuits, structures, and techniques have not been shown or described in detail so as not to obscure the examples. Identical numbers in two or more figures represent identical or similar elements.

[0088] Furthermore, the singular forms "a," "an," and "the" also include the plural forms unless otherwise indicated by the context. Additionally, the terms "comprises," "includes," "includes," and the like specify the presence of certain features, steps, processes, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, processes, elements, components, and / or groups. Components described as coupled may be directly coupled electronically or mechanically, or they may be coupled indirectly via one or more intermediate components, unless explicitly stated otherwise.Mathematical and geometric terms need not necessarily be used in accordance with their strict definitions unless the context of the description makes otherwise clear, because a person with normal technical knowledge would understand that, for example, an essentially similar element that functions in an essentially similar way could easily fall within the scope of a descriptive term, even if the term also has a strict definition.

[0089] And / or: Occasionally, the expression "and / or" is used here in conjunction with a list of items. This phrasing means that any combination of elements in the list—from a single element to all elements and any permutation in between—can be included. For example, "A, B and / or C" means "one of {A}, {B}, {C}, {A, B}, {A, C}, {C, B} and {A, C, B}".

[0090] Elements and their associated aspects that are described in detail in one example may, whenever practical, be included in other examples where they are not specifically shown or described. For example, if an element is described in detail with reference to one example and not described with reference to a second example, the element may still be claimed to be included in the second example.

[0091] Unless otherwise stated herein or evident from the context, the use of approximate terms such as "essentially," "approximately," "about," "about," "roughly," and the like is to be understood as not requiring mathematical precision and instead referring to a range of variation that includes, but is not strictly limited to, the stated value, property, or ratio. In particular, the range of variation implied by the use of such an approximate term includes, in addition to any explicitly stated ranges herein (if any), at least all immaterial variations and also those variations that are typical in the relevant field for the type of item in question due to manufacturing or other tolerances.In any case, the range of variation may include values ​​that are within ±1% of the specified value, property or ratio, unless otherwise stated.

[0092] Further modifications and alternative examples are obvious to the person skilled in the art in view of the present disclosure. For example, the devices and methods may include additional components or steps that have been omitted from the diagrams and descriptions for the sake of clarity. Accordingly, this description is to be understood as merely illustrative and serves the purpose of conveying to the person skilled in the art the general manner of carrying out the present teaching. The various examples shown and described here are to be understood as exemplary.Elements and materials, as well as arrangements of these elements and materials, may be used instead of those presented and described herein; parts and methods may be reversed; and certain features of the present teaching may be used independently, as is obvious to a person skilled in the art after reviewing the present description. Modifications may be made to the elements described herein without departing from the scope of the present teaching and the following claims.

[0093] It goes without saying that the examples presented here are not limiting and that changes to the structure, dimensions, materials and processes can be made without exceeding the scope of the present teaching.

[0094] Further examples in accordance with the present disclosure will be apparent to the person skilled in the art from consideration of the description and the practice of the invention disclosed herein. It is intended that the description and the examples be regarded as merely illustrative, and that the following claims have their full scope, including equivalents, under applicable law.

Claims

[1] Power-over-Ethernet (PoE) power supply device (PSE) (110) comprising the following: Ports (140) that can be connected via respective communication links to PoE-powered devices (PDs) (200) to power the PDs and exchange communications with them; and a control circuit (150) configured to operate in a state where a plurality of PDs (200) are connected to the terminals: from the multitude of PDs, link-layer protocol communications (160) are received, each comprising an alternative power field (161) indicating whether the PD that sent the respective communication has an alternative power source; and sets power priorities for the multitude of PDs at least partially based on the respective alternative power fields of the communications, in order to reduce a power priority of a first PD of the multitude of PDs relative to a standard value for the first PD if the first PD has an alternative power source (202). [2] PSE according to claim 1, where setting the power priorities for the multitude of PDs includes, at least partially, the control circuit based on the respective alternative power fields of the communications: Standard values ​​for the performance priorities of the multitude of PDs were determined; and The power priority of the first PD of the multitude of PDs is set to an adapted value that is lower than the default value for the first PD, in response to the alternative power field of the communication received by the first PD, which indicates that the first PD has an alternative power source. [3] PSE according to claim 1, wherein the setting of the power priorities for the plurality of PDs comprises, at least partially based on the respective alternative power fields of the communications, the control circuit: Standard values ​​for performance priorities were determined for the multitude of PDs; sets the power priorities of all PDs that do not have an alternative power source, as indicated by the alternative power fields, to their respective default values; and sets the power priorities of all PDs that have an alternative power source, as indicated by the alternative power fields, to respective adapted values ​​that are lower than the respective standard values ​​for the respective PDs. [4] PSE according to claim 1, wherein the setting of the power priorities for the plurality of PDs comprises at least partially based on the respective alternative power fields of the communications comprising the control circuit reducing the power priorities of all PDs having an alternative power source, as specified by the alternative power fields, relative to their respective standard values. [5] PSE according to claim 1, wherein setting the power priorities for the plurality of PDs comprises, at least partially based on the respective alternative power fields of the communications, that the control circuit for each of the PDs having an alternative power source is as specified by the alternative power fields,: determines whether the alternative power source of the respective PD is appropriate; and In response to a determination that the alternative power source of the respective PD is appropriate, the power priority of the respective PD is reduced relative to a standard power priority value for the respective PD. [6] PSE according to claim 1, wherein each alternative power field indicating the presence of an alternative power source also indicates a type of alternative power source. [7] PSE according to claim 6, wherein the control circuit is configured to negotiate with a given PD to terminate the power supply to the given PD in response to the alternative power field of a communication received by the given PD indicating that a certain type of AC power source is present. [8] PSE according to claim 6, wherein the types of alternative power sources that can be specified by the alternative power fields include: a battery, a local power supply and / or a connection to a second PSE. [9] PSE according to claim 8, wherein each alternative power field indicating that the transmitting PD has a battery also indicates an estimated operating time and / or state of charge of the battery. [10] PSE according to claim 9, wherein the control circuit is configured to compare, for each PD that has a battery as specified by the alternative power fields, the estimated runtime and / or state of charge of the battery with a threshold value and: to set the power priority of the respective PD to a default value if the estimated runtime and / or the battery's state of charge is below the threshold; and to set the power priority of the respective PD to an adjusted value that is lower than the standard value, in response to the estimated runtime and / or battery state of charge being greater than the threshold. [11] PSE according to claim 1, wherein the control circuit is configured to detect a change in the state of the system and, in response to the detection of the change in state, to reset the power priority of one or more PDs from a previously assigned adjusted value to a standard value. [12] PSE according to claim 1, wherein the alternative power field comprises a time-length-value (TLV) data structure of a data unit of the link layer protocol. [13] Power-over-Ethernet (PoE) powered device (PD) (200) comprising the following: a port (271) that can be connected via a communication link to a PoE power supply device (PSE) (110) to receive power from the PSE and exchange communications with it; and a control circuit (270) configured to: determines whether the PD has access to a power source other than the PSE; via the connection a link-layer protocol communication (160) to the PSE, which includes an alternative power field (161) that indicates whether the PD has the alternative power source in order to reduce a power priority of the PD relative to a default value for the PD when the PD has an alternative power source (202). [14] PD according to claim 13, wherein the control circuit is configured to respond to the determination that an alternative power source is available for the PD by: a type of alternative power source is determined, and specifies the type of alternative power source in the alternative power field of communication. [15] PD according to claim 14, wherein the types of alternative power sources detected by the control circuit include a battery, a local power supply and a connection to a second PSE. [16] PD according to claim 15, wherein the control circuit is configured to indicate, in response to the determination that an alternative power source is available for the PD and that the alternative power source is a battery, an estimated runtime and / or battery charge level in the alternative power field of communication. [17] PD according to claim 13, wherein the link layer protocol is one of the following: Link Layer Discovery Protocol (LLDP), Cisco Discovery Protocol (CDP), Foundry Discovery Protocol (FDP), Nortel Discovery Protocol (NDP), or Link Layer Topology Discovery (LLTD). [18] PD according to claim 13, wherein the alternative power field comprises a time-length-value (TLV) data structure of a data unit of the link layer protocol. [19] System comprising the following: one or more Power-over-Ethernet (PoE) powered devices (PDs) (200), each PD comprising: a PD-PoE port (271); and PD control circuits (270); and a PoE Power Supply Equipment (PSE) (110) comprising the following: PSE-PoE ports (140) that can be connected via respective communication links to the respective PD-PoE ports of the PDs to power the PDs and exchange communications with them; and a PSE control circuit (150), wherein the PD control circuit of each of the PDs is configured to send a link-layer protocol communication (160) to the PSE in a state in which the respective PD is connected to one of the PSE PoE ports, which includes an alternative power field (161) indicating whether the respective PD has an alternative power source (202); where the PSE control circuit is configured to be in a state where the PDs are connected to the PSE PoE ports: from the PDs, which receives communications of the link-layer protocol; and The respective power priorities for the PDs are set at least partially based on whether the PDs have the respective alternative power sources as specified in the respective alternative power fields of the communication, in order to reduce the power priority of one PD relative to a standard value for the PD if the PD has an alternative power source. [20] System according to claim 19, wherein the link layer protocol is one of the following: Link Layer Discovery Protocol (LLDP), Cisco Discovery Protocol (CDP), Foundry Discovery Protocol (FDP), Nortel Discovery Protocol (NDP), or Link Layer Topology Discovery (LLTD); and wherein the alternative power field comprises a time-length-value (TLV) data structure of a data unit of the link layer protocol.

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