Response mechanisms of a power sourcing equipment to a swap event of a power supply unit

Example implementations relate to a power sourcing equipment (PSE), and a method of reallocating power to one or more powered devices (PDs) by the PSE, before a swap event of a power supply unit (PSU). The method includes receiving an information about the swap event, determining based on the information that the swap event is expected to cause powering down of the one or more PDs, and requesting a first PD among the one or more PDs to permit the PSE to reduce an initial value of power allocated to the first PD. Further, the method includes reducing an amount of power to the first PD from the initial value to a reduced value of power based on a response from the first PD, and reallocating the reduced value of the power to the first PD to avoid powering down of the one or more PDs during the swap event.

BACKGROUND

Power over Ethernet (PoE) allows an Ethernet cable to be used for both power transmission and data transmission. Powered devices (PDs), such as Voice over Internet Protocol (VoIP) phones, Light-Emitting Diode (LED) lights, Internet Protocol (IP) cameras, wireless access points (APs), Bluetooth Low-Energy (BLE) beacons, or the like may be powered by PoE, and may therefore be installed in locations where it would be impractical or expensive to install wires to provide power.

A number of industry standards exist for providing PoE to the powered devices. For example, the Institute of Electrical and Electronics Engineers (IEEE) has defined at least three industry standards: i) IEEE 802.3af that allows up to 15.4 Watts to be delivered over Category 5 (Cat5) Ethernet cables; ii) IEEE 802.3at that allows up to 30 Watts to be delivered over Cat5 cables; and iii) IEEE 802.3bt that allows up to 71.3 Watts to be delivered over Cat5 cables. Further, LTPoE++ is a proprietary standard which allows up to 90 Watts to be delivered over Cat5 cables. In the IEEE standards, a device that receives PoE is called a Powered Device (PD), while a device that provides PoE is called a Power Sourcing Equipment (PSE).

It is emphasized that, in the drawings, various features are not drawn to scale. In fact, in the drawings, the dimensions of the various features have been arbitrarily increased or reduced for clarity of discussion.

DETAILED DESCRIPTION

For purposes of explanation, certain examples are described with reference to the components illustrated inFIGS.1-5. The functionality of the illustrated components may overlap, however, and may be present in a fewer or greater number of elements and components. Moreover, the disclosed examples may be implemented in various environments and are not limited to the illustrated examples. Further, the sequence of operations described in connection withFIG.5is an example and is not intended to be limiting. Additional or fewer operations or combinations of operations may be used or may vary without departing from the scope of the disclosed examples. Thus, the present disclosure merely sets forth possible examples of implementations, and many variations and modifications may be made to the described examples. Such modifications and variations are intended to be included within the scope of this disclosure and protected by the following claims.

Computing environments use networks, such as enterprise networks, datacenter networks, or other types of networks to support a wide variety of industries, institutions, etc. Increasingly, many of these networks include networking devices, such as network switches or network routers, which operate uninterruptedly to ensure that workloads deployed in computing environments are continuously available. Typically, each network switch includes conduits, such as Ethernet cables, to not only provide electronic communications, but also to provide power to each electronic device, e.g., each powered device (PD) connected to the network switch via a respective Ethernet cable. Lapses in providing power (i.e., Power over Ethernet (PoE)) for certain types of PDs may prove costly for such industries or institutions. Therefore, various industries and institutions, such as businesses, universities, governments, hospitals, or the like that use such networks often value reliability highly.

To facilitate increased reliability, the network switch (or a chassis having multiple network switches) is configured to receive power from multiple power supply units (PSUs) at a time. This redundancy of PSUs may prevent the network switch from shutting down entirely when a PSU among the multiple PSUs is swapped with a new PSU during a maintenance or service event of the PSU. Thus, the redundancy of the PSUs in the computing environment, may prevent a time-consuming reboot of the network switch. As used herein, the term “swap” may refer to a replacement of an old device with a new device, which may occur during a periodic maintenance or service event, for example.

The periodic swapping of the PSU with the new PSU may be required to reduce the failure of the PSUs due to prolonged and continuous usage of the PSUs over a period of time. In general, the PSU may fail due to a hardware failure, overheating, a failure of an electrical outlet into which the PSU is plugged, etc. Accordingly, such periodic swapping of the PSU may reduce PSU failure and an associated downtime of the computing environment which may have occurred otherwise due to the failure of the PSU.

However, during a swapping event, the amount of power flowing into the network switch is reduced. As a result, the amount of power that the network switch is able to provide to the PDs via the respective Ethernet cable may also be reduced. In other words, when the PSU supplying power to the network switch is swapped, the network switch may be obliged to stop providing PoE to a subset of the PDs that are connected to the network switch, in order to conserve power. For example, some ports on the network switch, which are designated as high priority ports, may continue providing PoE to the PDs connected thereto during a PSU swap event. However, some other ports on the network switch that are designated as low priority ports may be obliged to stop providing PoE to the PDs connected thereto during the PSU swap event. Thus, the PDs that are connected to the low priority ports may have to wait until the swap event of the PSU is completed to receive PoE again. It may be noted that the PDs that are connected to the high priority ports are known as high priority PDs and the PDs that are connected to the low priority ports are known as low priority PDs. Accordingly, some of the low priority PDs that are backed up by batteries may be able to postpone shutting down for a short period of time, but may be obliged to shut down if PoE does not become available again within the short period of time. If such PDs do shut down, the reboot process of such PDs may cause a further delay after the swap event is completed.

Further, the PD's use a Link Layer Discovery Protocol (LLDP) protocol to exchange a series of communications, such as one-way communications with the PSE. In particular, the current LLDP protocol supports a PD to simply request for power from a PSE, and the PSE can choose whether to comply by providing the requested amount of power. Moreover, the current LLDP protocol provides no way for a PSE to request that a PD accept a lower power allocation after the initial allocation of power to the PD. Thus, under the constraints of existing LLDP protocol-based systems, there would be no way for the PSE to request that the one or more PDs accept a lower amount of power allocation in response to the swap event of the PSU so that the PSE could reallocate a reduced amount of the power to one or more PDs. As a result, the potential capacity to keep powering the one or more PDs during the swap event of the first PSU132is diminished.

Systems and methods described herein provide a way for a power sourcing equipment (PSE), for example, a network switch, to continue providing some amount of power (or PoE) to one or more PDs that are connected to low priority ports during a swap event of a PSU among a plurality of PSUs until the swap event is completed. For example, before the swap event has started, the PSE may reduce an amount of power from an initial value of power allocated to the one or more PDs connected to the low priority ports to a reduced power value. Further, the PSE may reallocate and provide a reduced amount of power to the one or more PDs in order to avoid powering down of the one or more PDs during the swap event of the PSU. As described in further detail below, the PSE, upon receipt of information about the swap event of the PSU, can communicate to the one or more low priority PDs (and/or to the one or more high priority PDs) to notify those PDs that the PSU swap event is expected to occur. Accordingly, the PSE can negotiate with those low priority PDs first (and optionally with the high priority PDs later) to reduce some amount of power from the initial value of power that has been allocated to, but is not being completely used by, each of those one or more low priority PDs. Hence, the reduced value of power from those one or more low priority PDs can be used to offset the power deficit which might occur during the swap event of the PSU. This may avoid the need to power down of the one or more low priority PDs during the swap event of the PSU. Accordingly, the PSE may uninterruptedly provide power to the plurality of PDs during the swap event of the PSU without powering down the one or more low priority PDs, thus avoiding the downtime and/or reboot time of the one or more low priority PDs after the swap event.

Accordingly, the present disclosure describes example implementations of a power sourcing equipment (PSE), and an associated method for reallocation of power (or Power over Ethernet (PoE)) to one or more powered devices (PDs) connected to the PSE, before a swap event of a power supply unit (PSU) among a plurality of PSUs. Thus, the PSE may be able to prevent powering down of the one or more PDs during the swap event. In some examples, the method includes receiving an information about the swap event of the PSU among the plurality of PSUs connected to the PSE. The method further includes determining based on the information that the swap event is expected to cause powering down of the one or more PDs based on a priority of the plurality of PDs. Further, the method includes requesting a first PD among the one or more PDs to permit the PSE to reduce the initial value of power allocated to the first PD. The method further includes reducing an amount of power to the first PD from the initial value of power allocated to the first PD to a reduced value of power based on a response from the first PD to the request from the PSE for reducing the power. Further, the method includes reallocating and providing the reduced value of power to the first PD to avoid powering down of the one or more PDs during the swap event.

FIG.1depicts a portion of a computing environment100, such as a production environment hosted in a datacenter. In general, the computing environment100uses networks, such as enterprise networks, datacenter networks, or other types of networks to support a wide variety of industries, and executes one or more workloads to deliver intended services to customers belonging to such wide variety of industries. In one or more examples, the computing environment100may be managed via an external computing system110. For example, an administrator115may access networking devices, such as a power sourcing equipment (PSE)120, and electronic devices, such as a plurality of powered devices (PDs)140, via the external computing system110to view/track operations of those devices, and further apply various actions on those devices to enable the computing environment100to operate uninterruptedly.

As shown in the example ofFIG.1, the computing environment100includes the PSE120, a plurality of power supply units (PSUs)130, and the plurality of PDs140. The PSE120may be communicatively connected to the external computing system110over a TCP/IP (Transmission Control Protocol/Internet Protocol) network (not labeled), or the like without deviating from the scope of the present disclosure. Further, the PSE120is connected to the plurality of PSUs130via power cables (not labeled), and to the plurality of PDs140via a plurality of Ethernet cables150.

In some examples, the PSE120may refer to a kind of networking equipment (or device), which is responsible for transmitting power (e.g., Power over Ethernet (PoE)) and transceiving data to connected devices. In some non-limiting examples, the PSE120may be a network switch, a multi-slot chassis containing multiple network switches, a router, or the like. In certain examples, the network switch is commonly called an endspan device (as per Institute of Electrical and Electronics Engineers (IEEE) 802.3af), or an intermediary device disposed between a non-PoE-capable switch and a PoE device, or an external PoE injector called a mid-span device. In one or more examples, the PSE120includes a plurality of ports122,124,126,128, for example, a plurality of Ethernet ports, where each Ethernet port may be compatible for receiving an Ethernet jack of the corresponding Ethernet cable of the plurality of Ethernet cables150.

In some examples, the plurality of PSUs130may be connected to a main power source of the datacenter for receiving main alternating current (AC) power, convert the main AC power to direct current (DC) power, and transmit the DC power to the PSE120. In some examples, the plurality of PDs140may refer to a kind of electronic device, which is connected to the PSE120via the respective Ethernet cable of the plurality of Ethernet cables150. In such examples, each of the plurality of PDs140may receive power from the PSE120and transceive data with the PSE120via the respective Ethernet cable of the plurality of Ethernet cables150. In some non-limiting examples, the plurality of PDs140may be Voice over Internet Protocol (VoIP) phones, Light-Emitting Diode (LED) lights, Internet Protocol (IP) cameras, wireless Access Points (APs), Bluetooth Low-Energy (BLE) beacons, or the like.

Persons of skill in the art will understand that the PSE120and each of the plurality of PDs140may include a processing resource and machine-readable medium (e.g., memory) to facilitate the execution of the functionality described herein. In some examples, the processing resource may be a physical processor. In some examples, the physical processor may be at least one of a central processing unit (CPU), a microprocessor, and/or other hardware devices suitable for performing the functionality described herein. In some examples, the machine-readable medium is non-transitory and is alternatively referred to as a non-transitory machine-readable medium.

As shown inFIG.1, the PSE120includes a first port122, a second port124, a third port126, and a fourth port128. Within the PSE120, each of the plurality of ports122,124,126,128may be assigned a priority value (e.g., a Spanning Tree Port Priority value). In some examples, each of the first port122and the second port124is assigned a low priority value, and hence each of the first port122and the second port124is categorized as a low priority port. Similarly, in some examples, each of the third port126and the fourth port128is assigned a high priority value, and hence each of the third port126and the fourth port128is categorized as a high priority port. Further, as shown inFIG.1, the plurality of PSUs130includes a first PSU132and a second PSU134both connected to the PSE120via cables for supplying power to the PSE120. In some examples, the first PSU132may have a first power supply rating and a second PSU134may have a second power supply rating. As shown inFIG.1, the plurality of PDs140includes a first PD142, a second PD144, a third PD146, and a fourth PD148. In some examples, the first and second PDs142,144respectively, may be referred to as a low priority PDs140-1, whereas the third and fourth PDs146,148respectively, may be referred to as a high priority PDs140-2. In such examples, the first PD142is connected to the first port122via a first Ethernet cable152, and the second PD144is connected to the second port124via a second Ethernet cable154. Similarly, the third PD146is connected to the third port126via a third Ethernet cable156, and the fourth PD148is connected to the fourth port128via a fourth Ethernet cable158. In some examples, each of the plurality of Ethernet cables150may be a Cat5 cable.

In some examples, the PSE120may receive about 680 Watts to 1600 Watts of rated power from the plurality of PSUs130. In such examples, the PSE120may supply about 370 Watts to 1440 Watts of PoE to the plurality of PDs140. In some non-limiting examples, the computing environment100may include two PSEs120and forty-eight PDs140. In such examples, each PSE may receive about 1600 Watts of rated power from the plurality of PSUs130, and may supply about 60 Watts of PoE to each of the plurality of PDs140.

During operation, each of the plurality of PSUs130supplies power to the PSE120via the respective cable. Accordingly, the PSE120may transceive data, and transmit power to the plurality of PDs140via the plurality of Ethernet cables150. In such examples, when each of the plurality of PDs140is initially connected to the PSE120by the respective Ethernet cable of the plurality of Ethernet cables150, each of the plurality of PDs140and the PSE120may exchange a series of communications that conform to the Link Layer Discovery Protocol (LLDP). The LLDP is a vendor-neutral link layer protocol used by network devices to communicate information such as device identities, device capabilities, port names and descriptions, medium access control (MAC) and Physical (PHY) layer information, and medium dependent interface (MDI) information.

In one or more examples, through such series of LLDP communications, each of the plurality of PDs140may request that the PSE120supply power over Ethernet (PoE) to the respective PD of the plurality of PDs140. In some examples, each of the plurality of PDs140may request power based on an actual power requirement and a margin power requirement of the respective PD. In some examples, the term “actual power requirement” may refer to an absolute power that the PD may consume while handling a normal workload. Further, the term “margin power requirement” may refer to a buffer power that the PD may additionally require to handle an additional workload (or overload). The PSE120may elect to comply with the request or reject the request. The PSE120may reject the request for power allocation from each of the plurality of PDs140if a total power requested from the plurality of PDs140exceeds a total power supply rating of the plurality of PSUs130connected to the PSE120, for example. Similarly, the PSE120may accept the request for power allocation from each of the plurality of PDs140if the total power requested from the plurality of PDs140does not exceed the total power supply rating of the plurality of PSUs130connected to the PSE120, for example. In such examples, if the PSE120complies, the PSE120allocates an initial value (amount) of power to each of the plurality of PDs140(e.g., up to 90 Watts to each of the high priority PDs140-2, and 60 Watts to each of the low priority PDs140-1, if each of the plurality of Ethernet cables150is a Cat5 cable) and provides the allocated initial value of power to the respective PD of the plurality of PDs140.

At times, the administrator115may send a command to the PSE120via the external computing system110, about a swap event of at least one PSU, for example, a first PSU132among the plurality of PSUs130. In some examples, the command may specify an approximate initiation time of the swap event, which may be a useful time window for the PSE120to negotiate, reduce, reallocate, and provide the power to each of the plurality of PDs140. In such examples, such command from the external computing system110may trigger a rapid power-down (RPD) signal or a multi-priority rapid power-down (MPRPD) signal within the PSE120.

In some examples, upon generation of such RPD or MPRPD signal (i.e., before the swap event), the PSE120may determine that the swap event of the first PSU132is expected to cause powering down of one or more powered devices (PDs) among a plurality of PDs140connected to the PSE120. For example, the PSE120may calculate a power supply rating of remaining PSUs among the plurality of PSUs130and compare it with the total power requirement of the plurality of PDs140to determine whether the swapping event of the first PSU132results in a power deficit to continue providing the initial value of power allocated to the plurality of PDs140. For example, if the amount of power that the second PSU134(i.e., the remaining PSU) provides to the PSE120during the swap event of the first PSU132is sufficient for the PSE120to continue providing the initial amount of power allocated to each of the plurality of PDs140, then the PSE120may not communicate and/or negotiate with any of the plurality of PDs140for reducing and/or reallocating the power. Alternatively, if the amount of power that the second PSU134provides to the PSE120during the swap event of the first PSU132is insufficient for the PSE120to continue providing the initial amount of power allocated to the plurality of PDs140, then the PSE120may react to the RPD or MPRPD signal by sending a first network communication to the plurality of PDs140indicating that the swap event of the first PSU132is about to occur and negotiate with one or more PDs of the plurality of PDs140based on a priority of the plurality of PDs140for reducing and/or reallocating the power.

For example, the PSE120may first negotiate with one or more PDs among the low priority PDs140-1(i.e., based on a lower priority of the plurality of PDs140), and later optionally with one or more PDs among the high priority PDs140-2(i.e., based on the higher priority of the plurality of PDs140), to reduce an amount of power from the one or more PDs among the low priority PDs140-1or the high priority PDs140-2. Accordingly, the PSE120may try to avoid powering down of the one or more PDs among the plurality of PDs140during the swap event of the first PSU132.

In the current LLDP protocol, a PD simply requests power from a PSE, and the PSE can choose whether to comply by providing the requested amount of power. Similarly, the current LLDP protocol provides no way for a PSE to request that a PD accept a lower power allocation after the initial allocation of power to the PD. Thus, under the constraints of existing LLDP protocol-based systems, there would be no way for the PSE120to request that the one or more PDs among the plurality PDs140accept a lower amount of power allocation in response to the swap event of the first PSU132so that the PSE120could reallocate a reduced amount of the power to one or more PDs among the low priority PDs140-1. As a result, the potential capacity to keep powering the one or more PDs among the plurality of PDs140during the swap event of the first PSU132is diminished.

Using the systems and methods described herein, before the swap event of the first PSU132, the PSE120can request that the first PD142accept a lower amount of power than was initially allocated by sending a first network communication. The first PD142may opt to continue operating in a normal mode or switch to a power-saving mode based on the request from the PSE120, and may send a second network communication to the PSE120. In some examples, the first and second network communications are performed based on the LLDP protocol. Accordingly, the PSE120can reduce the amount of power allocated to the first PD142to a reduced value of power. Further, the PSE120may determine whether an amount of power reduced from the first PD142is sufficient to offset the deficit of the power due the swap event of the first PSU132. If the PSE120determines that the amount of power reduced from the first PD142is insufficient to offset the deficit of the power due to the swap event of the first PSU132, then the PSE120may further negotiate with the second PD144to accept a lower amount of power than was initially allocated to the second PD144. Similarly, the second PD144may opt to continue operating in the normal mode or switch to the power-saving mode based on the request from the PSE120. Accordingly, the PSE120can reduce the amount of power allocated to the second PD144to the reduced value of power. Further, the PSE120may determine whether the amount of power reduced from the second PD142is sufficient to offset the remaining power deficit due to the swap event of the first PSU132. Accordingly, if the PSE120determines that the amount of power reduced from the second PD144is sufficient to offset the remaining power deficit due to the swap event of the first PSU132, then the PSE120may stop negotiating with any other PD among the plurality of PDs140and allocate a respective reduced amount of power to each of the first and second PDs142,144. Once the reallocation is complete, the PSE120provides the respective reduced amount of power to each of the first and second PDs142,144via respective first and second ports122,124and respective first and second Ethernet cables152,154. In this manner, the PSE120may be able to re-negotiate the amount of power allocated to the first and second PDs142,144(i.e., low priority PDs140-1) so that both the first and second PDs142,144may be powered during the swap event of the first PSU132.

In some examples, to facilitate this re-negotiation of the amount of power allocated to the first PD142and/or to the second PD144, an additional Type-Length-Value (TLV) can be added to the LLDP protocol. The additional TLV can include at least one bit that serves as a PSU swap status. The bit may include two values, for example, a first value of the bit and a second value of the bit. In one or more examples, the first value of the bit may function as a swap status indicator of the first PSU132and the second value of the bit may function as the swap status indicator of the second PSU134. Each of the first value of the bit and the second value of the bit may either have “zero value” or “one value”. In some examples, the one value may represent that the swap event of the PSU is about of occur and the zero value may represent that the swap event of the PSU is not occurring. In some examples, the first value of the bit having the one value may indicate that the PSU swap event for the first PSU132is about to occur, while a second value of the bit having the zero value may indicate that the PSU swap event for the second PSU134is not occurring. The additional TLV may also include one or more bits that indicate whether the first PD142, for example, has opted to switch to the power-saving mode or continue to operate in the normal mode, based on the request from the PSE120. Furthermore, the additional TLV may include a plurality of bits that indicate how much power (e.g., minimum power) the first PD142may have to receive from the PSE120in order to operate in the power-saving mode or the amount of power (i.e., maximum power) that the first PD142may expect to consume while operating in the power-saving mode. Also, the TLV may include a plurality of bits that indicate an amount of power (i.e., maximum power) that the first PD142may expect to consume while operating in the normal mode or how much power (e.g., minimum power) that the first PD142may have to receive from the PSE120in order to operate in the normal mode.

The additional TLV allows the PSE120to have multiple options while negotiating with the first PD142to reduce the amount of power initially allocated to the plurality of PDs140. For example, if the first PD142has opted to switch to the power-saving mode, the PSE120can reduce the amount of power initially allocated to the first PD142to an amount that the additional TLV indicates that the first PD142must receive in order to operate in the power-saving mode. Once the PSE120updates the reduced amount of power allocated to the first PD142, the PSE120can check whether the amount of power reduced from the first PD142is sufficient to offset the deficit of power due to the swap event of the first PSU132. If the amount of power reduced from the first PD142among the one or more PDs in the low priority PDs140-1is sufficient, then the PSE120may not negotiate with any other PDs among the plurality of PDs140. However, if the amount of power reduced from the first PD142is insufficient to offset the deficit of power due to the swap event of the first PSU132, then the PSE120may repeat the aforementioned steps for the second PD144among the one or more PDs in the low priority PDs140-1.

On the other hand, if the first PD142has opted to continue operating in the normal mode (i.e., unwilling to switch to the power-saving mode), then the PSE120can reduce the initial value of power allocated to the first PD142to a maximum amount that the first PD142is expected to consume, for example, the actual power requirement of the first PD142. Once the PSE120updates the amount of power allocated to the first PD142, the PSE120can check whether the amount of power reduced from the first PD142is sufficient to offset the deficit of power due to the swap event of the first PSU132. If the amount of power reduced from the first PD142among the one or more PDs in the low priority PDs140-1is sufficient, then the PSE120may not negotiate with any other PDs among the plurality of PDs140. However, if the amount of power reduced from the first PD142is insufficient to offset the deficit of power due to the swap event of the first PSU132, then the PSE120may repeat the aforementioned steps for the second PD144among the one or more low priority PDs140-1.

In some examples, after reallocating and providing the reduced value of power to the first and second PDs142,144among the one or more PDs in the low priority PDs140-1, the PSE120may initiate a pre-determined time period for completing the swap event from the administrator115. The PSE120may communicate the pre-determined time period to the administrator115via the external computing system110. In some examples, after the swap event of the first PSU132is completed with a swapped PSU, the PSE120may be notified about the completion of the swap event. In some other examples, after the completion of the swap event of the first PSU132with the swapped PSU, the PSE120may receive additional power and may automatically be notified about the completion of the swap event.

In some examples, the PSE120may determine whether the swap event is completed within the pre-determined time period. If the swap event has been completed within the pre-determined time period, then the PSE120may further determine a power supply rating of a swapped PSU. Accordingly, the PSE may determine whether the swapped PSU has the power supply rating greater than or equal to an old power supply rating of the first PSU132(or an older PSU). In some examples, if the PSE120determines that the power supply rating of the swapped PSU is greater than or equal to the first power supply rating of the first PSU132, then the PSE120may restore the initial value of power allocated to each of the plurality of PDs140. In some other examples, if the PSE120determines that the power supply rating of the swapped PSU is less than the first power supply rating of the first PSU132, then the PSE120may communicate to the external computing system110about powering down the one or more PDs in the low priority PDs140-1based on the priority for accommodating the power supply rating of the swapped PSU. In some examples, the term “accommodating” the power supply rating of the swapped PSU may refer to using the power provided from the swapped PSU to supply PoE to remaining PDs (i.e., non-powered down PDs) among the plurality of PDs140.

In some other examples, when the PSE120determines that the swap event is not completed within the pre-determined time period, then the PSE120may restore the initial value of power allocated to each of the plurality of PDs140. In other words, in response to non-completion of the swap event within the pre-determined time period, the PSE120may restore the initial value of power allocated to each PD among the plurality of PDs140.

A non-limiting example implementation of the swap event is discussed herein. In some examples, the first power supply rating of the first PSU132may be around 60 Watts and the second power supply rating of the second PSU134may be around 240 Watts. Similarly, each of the first and second PDs142,144respectively, may have a power requirement of about 60 Watts. Further, each of the third and fourth PDs146,148respectively, may have a power requirement of about 90 Watts. In such examples, the PSE120may receive a total power of about 300 Watts and the PSE120may have to transmit about 300 Watts of power to the plurality of PDs140. In some examples, when the first PSU132is expected to undergo a swap event, the PSE120may expect a power deficit of about 60 Watts. Therefore, the PSE120may be able to transmit about 240 Watts to the plurality of PDs140. In such examples, the PSE120may first negotiate with the first PD142among the one or more PDs in the low priority PDs140-1based on the priority value of the plurality of PDs140. If the first PD142has opted to switch to the power-saving mode, then the first PD142may indicate how much power it has to receive in order to operate in the power-saving mode. In some examples, the first PD142may indicate about 10 Watts as the amount of power that the first PD142is expected to consume while operating in the power-saving mode. In that case, the PSE120may reduce about 50 Watts (i.e., the difference between the initial allocated power of 60 Watts and the 10 Watts maximum expected to be consumed during power-saving mode) from the first PD142and re-allocate 10 Watts to the first PD142. Further, the PSE120may compare the amount of power reduced from the first PD142with the power deficit due to the swap event of the first PSU132. For example, the PSE120may determine that the deficit is still about 10 Watts. In such examples, the PSE120may further negotiate with the second PD144among the one or more PDs in the low priority PDs140-1based on the priority value of the plurality of PDs140. If the second PD142has opted (or is only willing) to operate in the normal mode, then the second PD144may indicate how much maximum amount of power that the second PD144is expected to consume while operating in the normal mode. In some examples, the second PD144may indicate about 50 Watts as the maximum amount of power that the second PD144is expected to consume while operating in the normal mode (or how much minimum amount of power that the second PD144has to receive from the PSE120in order to operate in the normal mode). In such a case, the PSE120may reduce about 10 Watts (i.e., the difference between the initial allocated power of 60 Watts and the 50 Watts expected to be consumed) from the second PD144and re-allocate 50 Watts to the second PD144. Further, the PSE120may compare the reduced value of power from the second PD144with the remaining power deficit due to the swap event of the first PSU132. For example, the PSE120may determine that the remaining power deficit is 0 Watts. In such examples, the PSE120may not negotiate with any other PDs among the plurality of PDs140. Accordingly, the PSE120may reallocate the reduced value of power to the first and second PDs142,144respectively, provide the corresponding reduced value of power to the first and second PDs142,144respectively, and communicate to the external computing system110to initiate the swap event.

Another non-limiting example implementation of the swap event is discussed herein. In some other examples, the first power supply rating of the first PSU132may be around 60 Watts, and the second power supply rating of the second PSU134may be around 240 Watts. Similarly, each of the first and second PDs142,144respectively, may have a power requirement of about 60 Watts. Further, each of the third and fourth PDs146,148respectively, may have a power requirement of about 90 Watts. In such examples, the PSE120may receive a total power of about 300 Watts, and the PSE120may have to transmit about 300 Watts of power to the plurality of PDs140. In some examples, when the first PSU132is expected to undergo the swap event, the PSE120may expect a power deficit of about 60 Watts. Therefore, the PSE120may be able to transmit about 240 Watts to the plurality of PDs140. In such examples, the PSE120may negotiate with the first PD142among the one or more PDs in the low priority PDs140-1based on the priority value of the plurality of PDs140. If the first PD142has opted to continue operating in the normal mode, then the first PD142may indicate how much minimum power that it has to receive from the PSE120in order to operate in the normal mode or how much maximum power that the first PD142may expect to consume while operating in the normal mode. In some examples, the first PD142may indicate about 50 Watts, the PSE may reduce about 10 Watts from the first PD142and re-allocate 50 Watts to the first PD142. Further, the PSE120may compare the reduced amount of power from the first PD142with the power deficit due to the swap event of the first PSU132. For example, the PSE120may determine that the deficit is still about 50 Watts. In such examples, the PSE120may further negotiate with the second PD144among one or more PDs in the low priority PDs140-1based on the priority value of the plurality of PDs140. If the second PD142has opted to continue operating in the normal mode, then the second PD144may indicate how much maximum amount of power that the second PD144is expected to consume while operating in the normal mode or how much minimum amount of power that the second PD144has to receive from the PSE120in order to operate in the normal mode. In some examples, the second PD144may indicate about 50 Watts, and the PSE120may reduce about 10 Watts from the second PD144and re-allocate 50 Watts to the second PD144. Further, the PSE120may compare the reduced value of power from the second PD144with the remaining power deficit due to the swap event of the first PSU132. For example, the PSE120may determine that the deficit is still about 40 Watts. In such examples, the PSE120may further negotiate with a third PD146among the one or more PDs in the high priority PDs140-2. If the third PD146has opted to switch to the power-saving mode, then the third PD146may indicate how much power it has to receive in order to operate in the power-saving mode. In some examples, the third PD146may indicate about 50 Watts, then the PSE may reduce about 40 Watts from the third PD146. In some examples, the PSE120may then communicate to the external computing system110about the reduced value of power for each of the first, second, and third PDs142,144,146respectively, and indicate the priority value of each of the first, second, and third PDs142,144,146. The administrator115of the external computing system110may access the communication from the PSE120and reply with an approval to reallocate the reduced value of power to each of the first, second, and third PDs142,144,146respectively. Alternately, the administrator115may disapprove the reduced value of power to the third PD146, since the third PD146has the high priority. Then, the PSE120may retain the initial value of allocated power to the third PD146, and power down the first and second PDs142,144respectively to offset the deficit of about 60 Watts due to the swap event of the first PSU132having the power supply rating of about 100 Watts.

While the PSE120, the plurality of PDs142,144,146,146, the plurality of Ethernet cables152,154,156,158, the plurality of ports122,124,126,128, the plurality of PSUs132,134are provided for illustrative purposes, persons of skill in the art will understand that no limitation on the number of PSEs, PDs, Ethernet cables, ports, or PSUs is intended thereby. Furthermore, the number of PSUs connected to a single PSE, the number of PDs connected to a single PSE, the number of PSEs connected to a single PD, and the number of Ethernet cables used to connect a PSE to a PD may all vary. For example, a single PD may be connected to a single PSE or multiple PSEs via more than one Ethernet cable (e.g., to receive more power via Ethernet than can be provided through a single port). Also, in some examples, PSEs and PDs may not necessarily be mutually exclusive. A PoE pass-through switch, for example, may concurrently act as both a PD (by receiving power through one Ethernet port) and a PSE (by providing power to another PD through another Ethernet port). In the case of a PoE pass-through switch, the PSEs that provide power to the PoE pass-through switch may serve the same role as the PSUs described herein.

FIG.2depicts a portion of another computing environment200according to another example of the present disclosure. The computing environment200is substantially similar to the computing environment100, as discussed hereinabove in the example ofFIG.1, except for a number of priority ports in a power sourcing equipment (PSE)220, and a number of powered devices (PDs)240connected to a respective port of the PSE220. In some examples, the computing environment200includes the PSE220, a plurality of power supply units (PSUs)230, and the PDs240.

In some examples, the PSE220may be a networking equipment (or device) which is responsible for transmitting power (e.g., Power over Ethernet (PoE)) and transceiving data to connected devices. For example, the PSE220may be a network switch, a multi-slot chassis containing multiple network switches, a router, or the like. The PSE220includes a plurality of ports222,224, for example, a plurality of Ethernet ports, where each Ethernet port may be compatible for receiving an Ethernet jack of a corresponding Ethernet cable of a plurality of Ethernet cables250. In some examples, each of the plurality of PSUs230may be a power management device, which converts alternating current (AC) to low-voltage regulated direct current (DC) power for supplying to the PSE220. Further, each of the plurality of PDs240may be electronic device, which is connected to the PSE220via the respective Ethernet cable of the plurality of Ethernet cables250. In such examples, each of the plurality of PDs240may receive power from the PSE120and transceive data with the PSE120via the respective Ethernet cable of the plurality of Ethernet cables250. In some non-limiting examples, the plurality of PDs240may be Voice over Internet Protocol (VoIP) phones, Light-Emitting Diode (LED) lights, Internet Protocol (IP) cameras, wireless access points (APs), Bluetooth Low-Energy (BLE) beacons, or the like.

As discussed hereinabove, persons of skill in the art will understand that the PSE220and each of the plurality of PDs240may include a processing resource and machine-readable medium (e.g., memory) to facilitate execution of the functionality described herein.

As shown inFIG.2, the PSE220includes a first port222and a second port224. Within the PSE220, each of the plurality of ports222,224may be assigned a priority value (e.g., a Spanning Tree Port Priority value). In some examples, the first port222is assigned a low priority value, and hence the first port222is categorized as a low priority port, and the second port224is assigned a high priority value, and hence the second port224is categorized as a high priority port. Further, as shown inFIG.2, the plurality of PSUs230includes a first PSU232and a second PSU234both connected to the PSE220via cables for supplying power to the PSE220. Similarly, as shown inFIG.2, the plurality of PDs240includes a first PD242and a second PD244. In some examples, the first PD242may be referred to as a low priority PD240-1, whereas the second PD244may be referred to as a high priority PD240-2. In such examples, the first PD242is connected to the first port222via a first Ethernet cable252, and the second PD244is connected to the second port224via a second Ethernet cable254. In some examples, each of the plurality of Ethernet cables250may be a Cat5 cable.

During operation, each of the plurality of PSUs230supplies power to the PSE220via the respective cable. Accordingly, the PSE220may transceive data, and transmit power to the plurality of PDs240via the plurality of Ethernet cables250. In such examples, when each of the plurality of PDs240is initially connected to the PSE220by the respective Ethernet cable of the plurality of Ethernet cables250, each of the plurality of PDs240and the PSE220may exchange a series of communications that conform to the Link Layer Discovery Protocol (LLDP). At times, the administrator215may send a command to the PSE220via the external computing system210, about a swap event of at least one PSU, for example, a first PSU232among the plurality of PSUs230.

Accordingly, the PSE220may determine that the swap event of the first PSU232is expected to cause powering down of one or more powered devices (PDs) among a plurality of PDs240connected to the PSE220. For example, the PSE220may calculate a power supply rating of remaining PSUs among the plurality of PSUs230, and compare it with the total power requirement of the plurality of PDs240, to determine whether the swapping event of the first PSU232results in a power deficit to continue providing the initial value of power allocated to the plurality of PDs240. For example, if the amount of power that the second PSU234(i.e., the remaining PSU) provides to the PSE220during the swap event of the first PSU232is sufficient for the PSE220to continue providing the initial amount of power allocated to each of the plurality of PDs240, then the PSE220may not communicate and/or negotiate with any of the plurality of PDs240for reducing and/or reallocating the power. Alternatively, if the amount of power that the second PSU234provides to the PSE220during the swap event of the first PSU232is insufficient for the PSE220to continue providing the initial amount of power allocated to the plurality of PDs240, then the PSE220sends a first network communication to the plurality of PDs240indicating that the swap event of the first PSU232is about to occur and negotiates with one or more PDs of the plurality of PDs240based on a priority of the plurality of PDs240for reducing and/or reallocating the power.

For example, the PSE220may first negotiate with one or more PDs among the plurality of PDs240based on a priority of the plurality of PDs240to reduce an amount of power from the one or more PDs among the plurality of PDs240. Accordingly, the PSE220may try to avoid powering down of the one or more PDs among the plurality of PDs240during the swap event of the first PSU232.

In one or more examples, before the swap event of the first PSU232, the PSE220may request that the first PD242accept a lower amount of power than was initially allocated by sending a first network communication. The first PD242may opt to switch to a power-saving mode or continue operating in a normal mode, based on the request from the PSE220, and may send a second network communication to the PSE220. Accordingly, the PSE220can reduce the amount of power allocated to the first PD242to a reduced value of power. Further, the PSE220may determine whether an amount of power reduced from the first PD242is sufficient to offset the deficit of the power due the swap event of the first PSU232.

In some examples, if the PSE220determines that the amount of power reduced from the first PD242is sufficient to offset the deficit of the power due to the swap event of the first PSU232, then the PSE220may not negotiate with any other PDs among the plurality of PDs240. Further, the PSE220may reallocate and provide the reduced value of power to the first PD242, and communicate to the external computing system210to initiate the swap event of the first PSU232.

In some other examples, if the PSE220determines that the amount of power reduced from the first PD242is insufficient to offset the deficit of the power due to the swap event of the first PSU232, then the PSE220may further negotiate with the second PD244(i.e., a high priority PD, since there are no more low priority PDs) to accept the lower amount of power than was initially allocated to the second PD244. If the second PD244has opted to operate in the power-saving mode based on the request from the PSE220, then the PSE220can reduce the amount of power allocated to the second PD244to the reduced value of power. However, before the PSE220allocates the reduced value of power to the second PD244(i.e., high priority PD), the PSE220may communicate to the external computing system210about the reduced value of power for each of the first PD242and the second PD244, and also indicate the priority value of each of the first PD242and the second PD244. The administrator215of the external computing system210may access the communication from the PSE220, and reply with an approval to reallocate the reduced value of power to each of the first PD242and the second PD244. Alternately, the administrator215may disapprove the reduced value of power to the second PD246based on its high priority. Then, the PSE220may retain the initial value of allocated power to the second PD246, and power down the first PD242to offset the power deficit due to the swap event of the first PSU232.

FIG.3depicts a block diagram of a PSE120including a processing resource160and a machine-readable medium170storing executable program instructions. It should be noted herein that the PSE120referred to inFIG.3is same as the PSE120that is described inFIG.1. In some examples, the processing resource160is operably coupled to the machine-readable medium170. The processing resource160may be a physical processor. In some examples, the physical processor may be a microprocessor suitable for performing the functionality described in relation toFIG.1. In some examples, the machine-readable medium170is non-transitory and is alternatively referred to as a non-transitory machine-readable medium. The processing resource160executes one or more program instructions (e.g., processing resource executable program instructions) to perform one or more functions described inFIG.1.

In some examples, the processing resource160may execute program instructions for receiving information about a swap event of a power supply unit (PSU) among a plurality of PSUs, as discussed in the example ofFIG.1. In one or more examples, the PSE is communicatively coupled to plurality of PSUs via cables and the plurality of PDs via a plurality of Ethernet cables. In some examples, the plurality of PDs may include one or more high priority PDs and one or more low priority PDs (e.g., spanning Tree Port Priority value).

The processing resource160may further execute program instructions for determining based on the information that the swap event is expected to cause powering down of one or more powered devices (PDs) among a plurality of PDs connected to the PSE, as discussed in the example ofFIG.1. For example, the PSE may calculate a power supply rating of remaining PSUs among the plurality of PSUs and compare with the total power requirement of the plurality of PDs to determine whether the swapping event of the PSU results in a power deficit to continue providing the initial value of power allocated to the plurality of PDs.

Further, the processing resource160may execute the one or more program instructions for requesting a first PD among the one or more PDs based on the priority of the plurality of PDs, to permit the PSE to reduce an initial value of power allocated to the first PD, as discussed in the example ofFIG.1. In some examples, the PSE120may send a first network communication to the first PD indicating the swap event of the PSU. For example, the first network communication may include a bit that indicates the swap event. In one or more examples, the PSE120may initially choose one or more PDs having a first priority value (e.g., a low priority value) for sending the first network communication, and request to reduce the initial value of power from those low priority PDs. Further, the PSE120may optionally choose one or more PDs having a second priority value (e.g., a high priority value) for sending the first network communication, and request to reduce the initial value of power from those high priority PDs.

The processing resource160may further execute the one or more program instructions for reducing an amount of power from the initial value of power to a reduced value of power based on a response from the first PD, as discussed in the example ofFIG.1. In some examples, the first PD may send a second network communication in response to the request from the first network communication from the PSE120. In some examples, the second network communication may include one or more bits that indicate whether the first PD has opted to switch to a power-saving mode, and a plurality of bits that indicates how much power the first PD has to receive in order to operate in the power-saving mode. In some other examples, the second network communication may include one or more bits that indicate the first PD has opted to continue operating in a normal mode, and a plurality of bits that indicate a maximum amount of power that the first PD is expected to consume while operating in the normal mode or how much minimum amount of power that the first PD has to receive from the PSE120to operate in the normal mode. Accordingly, the PSE120may reduce the amount of power to the first PD based on a response from the first PD.

Further, the processing resource160may execute the one or more program instructions for reallocating the reduced value of power to the first PD to avoid powering down the one or more PDs during the swap event, as discussed in the example ofFIG.1. In such examples, the processing resource160may execute the one or more program instructions to further determine if the reduced power from the first PSU is sufficient to offset the power deficit due to the swap event of the PSU. If the reduced power is sufficient to offset the power deficit, then the processing resource160may execute the one or more program instructions to communicate an external computing system to initiate the swap event and provide the reduced value of power to the first PD.

FIG.4depicts a block diagram400depicting a processing resource160and a machine-readable medium170encoded with example instructions executable by a power sourcing equipment (PSE) for reallocating power to one or more powered devices (PDs) before a swap event of a power supply unit (PSU). It should be noted herein that the PSE referred to inFIG.4may be the same or similar to PSE120described inFIGS.1and3. The machine-readable medium170is non-transitory and is alternatively referred to as a non-transitory machine-readable medium. In some examples, the machine-readable medium170may be accessed by the processing resource160. In some examples, the machine-readable medium170stores the program instructions corresponding to functionality of the PSE, as discussed inFIGS.1and3. The machine-readable medium170may be encoded, for example, with a first instruction402, a second instruction404, a third instruction406, a fourth instruction408, and a fifth instruction410.

The first instruction402, when executed by the processing resource160may implement aspects of receiving an information about a swap event of a PSU among a plurality of PSUs. In one or more examples, the PSE is communicatively coupled to the plurality of PSUs via cables and the plurality of PDs via a plurality of Ethernet cables. The step of receiving the information about the swap event is described in detail inFIG.1.

The second instruction404, when executed by the processing resource160may implement aspects of determining, based on the information that the swap event is expected to cause powering down of one or more PDs among a plurality of PDs connected to the PSE. The step of determining whether the swap event is expected to cause powering down of the one or more PDs among the plurality of PDs is described in detail inFIG.1.

The third instruction406when executed by the processing resource160may implement aspects of requesting a first PD among the one or more PDs to permit the PSE to reduce an initial value of power allocated to the first PD. In one or more examples, the PSE may choose to request one or more first priority PDs, and optionally followed by one or more second priority PDs to reduce the initial value of power allocated to the respective PDs. The step of requesting the one or more PDs are described in detail inFIG.1.

The fourth instruction408, when executed by the processing resource160may implement aspects of reducing an amount of power from the initial value of power to a reduced value of power based on a response from the first PD. In some examples, the first PD may choose to operate in a power-saving mode or a normal mode, and accordingly, the first PD may communicate to the PSE about the power requirement to operate in the corresponding mode. Accordingly, the PSE may reduce the amount of power from the first PD. The step of reducing the amount of power from the first PD is described in detail inFIG.1.

The fifth instruction410, when executed by the processing resource160may implement aspects of reallocating the reduced value of power to the first PD to avoid powering down of the one or more PDs during the swap event. In some examples, the processing resource160may be configured to further determine if the reduced power from the first PD is sufficient to offset the power deficit due to the swap event of the PSU. If the reduced power is sufficient to offset the power deficit, then the processing resource may be configured to communicate to an external computing system to initiate the swap event and provide the reduced value of power to the first PD. The step of performing the reallocating the reduced value of power to the first PD is described in detail inFIG.1.

FIG.5depicts a flow diagram depicting a method500of reallocating power to one or more powered devices (PDs) before a swap event of a power supply unit (PSU). It should be noted herein that the method500is described in conjunction withFIG.1. In one or more examples, a plurality of steps discussed herein in the method500is performed by a power sourcing equipment (PSE).

The method500starts at block502and continues to block504. At block504, the method500includes receiving an information about a swap event of a power supply unit (PSU), for example, a first PSU among a plurality of PSUs. In one or more examples, an administrator may send a command to the PSE via the external computing system, about the swap event of the first PSU. In one or more examples, the swap event may be part of a periodic maintenance or a service event of the first PSU to avoid the possible failure of the first PSU due to prolonged usage over a period of time. In some examples, each of the plurality of PSUs may have a power supply rating, which is indicative of the power that the corresponding PSU is capable of supplying to the PSE. The method500continues to block506.

At block506, the method500includes based on the information, determining that the swap event is expected to cause powering down of one or more powered devices (PDs) among a plurality of PDs based on a priority of the plurality of PDs, as described inFIG.1. In some examples, the PSE is connected to the plurality of PSUs via cables and to a plurality of PDs via a plurality of Ethernet cables. The method500continues to block508.

At block508, the method500includes requesting the first PD among the one or more PDs to permit the PSE to reduce an initial value of power allocated to the first PD, as described inFIG.1. In one or more examples, the PSE may choose the one or more PDs having a first priority (or low priority) to request for reducing the initial value of the power allocated to the first PD. In such examples, the PSE may send a first network communication to the selected PD, for example, the first PD among the one or more PDs to reduce the initial value of power due to the swap event of the first PSU. In some examples, the first PD may have a first priority value (or the low priority). The method500continues to block510.

At block510, the method500includes reducing an amount of power from the initial value of power to a reduced value of power based on a response from the first PD, as described inFIG.1. In some examples, upon receiving the first network communication from the PSE requesting for reducing the initial value of power, the first PD may opt to operate in a power-saving mode or a normal mode. Accordingly, the first PD may send a second network communication to the PSE to indicate its power requirement to operate in either the power-saving mode or the normal mode. Accordingly, the PSE may receive the second network communication from the first PD, and may reduce the amount of power to the first PD in accordance with the option selected by the first PD and the associated power requirement of the first PD. The method500continues to block512.

At block512, the method500includes reallocating the reduced value of power to the first PD to avoid powering down of the one or more PDs during the swap event, as described inFIG.1. The method500continues to block514. At block514, the method500includes determining if the amount of power reduced from the first PD is sufficient to avoid powering down of the one or more PDs. In other words, the PSE may determine if the amount of power reduced from the first PD is sufficient to offset the power deficit due to the swap event of the first PSU. Accordingly, if the PSE determines that the amount of power reduced from the first PD is sufficient to offset the power deficit due to the swap event of the first PSU i.e., “yes” at block514, the method500continues to block516.

At block516, the method500includes communicating to an external computing system to initiate the swap event. In some examples, the PSE may additionally provide details about the first PD, and its priority value to the external computing system. The method500continues to block518.

At block518, the method500includes providing the reduced value of power to the first PSU so as to avoid powering down of the one or more PDs during the swap event. In one or more examples, the PSE may initiate a pre-determined time period for completing the swap event to the external computing system. In some examples, if the swap event is not completed within the pre-determined time period, then the PSE may restore the initial value of power allocated to the first PD among one or more PDs. It may be noted that the term “not completed” may refer to non-initiating of the swap event from the administrator within the pre-determined time period. In such examples, the PSE may inform the administrator, that it would restore the initial value of power allocated to the first PD among one or more PDs, and request the administrator to reinitiate the process of sending the information about the swap event to the PSE. In some other examples, if the swap event is completed within the pre-determined time period, then the PSE may evaluate the power supply rating of a swapped PSU with that of an old power supply rating of the first PSU. Accordingly, if the PSE determines that the swapped PSU had the power supply rating greater than or equal to the old power supply rating of the first PSU, then the PSE may allocate the initial value of power to the first PSU after the swap event. However, if the PSE determines that the swapped PSU has the power supply rating lower than old power supply rating of the first PSU, then the PSE may communicate to the external computing system about powering down the first PD based on the priority, for accommodating the power supply rating of the swapped PSU. In other words, if the PSE determines that the swapped PSU has the lower power supply rating than the first PSU, then the PSE communicates to the external computing system about powering down the one or more PDs based on the priority for accommodating the power supply rating of the swapped PSU. The method500ends at block520. In some examples, the term “accommodating” the power supply rating of the swapped PSU may refer to using the power provided from the swapped PSU to supply PoE to remaining PDs (i.e., non-powered down PDs) among the plurality of PDs.

Referring back to the block514, if the PSE determines that the amount of power reduced from the first PD is insufficient to offset the power deficit due to the swap event of the first PSU i.e., “no” at block514, the method500continues to block522.

At block522, the method500includes repeating steps related to blocks508to512described hereinabove (or steps iii to v as recited in claim1of the present application) for a second PD among the one or more PDs to avoid powering down of the one or more PDs during the swap event. The method500continues to block524. In some examples, the second PD has the first priority (or the low priority), as in the case of first PD. However, in some other examples, the second PD may have a second priority (or a high priority).

At block524, the method500includes determining if the amount of power reduced from the second PD is sufficient to avoid powering down of the one or more PDs. In other words, the PSE may determine if the amount of power reduced from the second PD is sufficient to offset the power deficit due to the swap event of the first PSU. Accordingly, if the PSE determines that the amount of power reduced from the second PD is sufficient to offset the power deficit due to the swap event of the first PSU i.e., “yes” at block524, the method500continues to block526, only if the second PD has been assigned the first priority (i.e., low priority value).

At block526, the method500includes communicating to the external computing system to initiate the swap event of the first PSU. It may be noted herein, that the PSE may request the external computing system to initiate the swap event, if it determines that each of the first and second PDs has the first priority value (or a low priority value). In such examples, the method500continues to block528.

At block528, the method500includes providing the reduced value of power to the second PD so as to avoid powering down of the one or more PDs during the swap event of the first PSU. The method500ends at block520.

Referring back to the block524, if the PSE determines that the amount of power reduced from the second PD is still insufficient to offset the power deficit due to the swap event of the first PSU i.e., “no” at block524, the method500returns to block522, where the PSE may repeat the steps related to blocks508to512described hereinabove (or steps iii to v as recited in claim1of present application) for a remaining PD among the one or more PDs to avoid powering down of the one or more PDs during the swap event of the first PSU.

Again, referring back to the block524, if the PSE determines that the amount of power reduced from the second PD is sufficient to offset the power deficit due to the swap event of the first PSU i.e., “yes” at block524, the method500continues to block530, only if the second PD has been assigned the second priority value (i.e., a high priority value).

At block530, the method500includes communicating to the external computing system that the first PD has the first priority value and the second PD has the second priority value. In some examples, if an administrator of the external computing system provides approval to the reallocation of the power to the first and second PDs, then the method500continues to block532. At block532, the method500includes receiving approval for reallocation of the power to the first and second PDs from an administrator via the external computing system. In such examples, the method500continues to block528. As discussed hereinabove, at block528, the method500includes providing the reduced value of power to the first and second PDs so as to avoid powering down of the one or more PDs during the swap event of the first PSU. The method500ends at block520.

Referring back to block530, the method500includes communicating to the external computing system that the first PD has the first priority value and the second PD has the second priority value. If the administrator of the external computing system provides disapproval to the reallocation of the power to the second PD, then the method500continues to block534. At block534, the method500includes receiving disapproval for reallocation of the power to the second PD from the administrator of the external computing system. In such examples, the method500continues to block536. As discussed hereinabove, at block534, the method500includes rejecting the reduced value of power to the second PD, since the second PD has the high priority value. The method500continues to block536. At block536, the method500includes communicating to the external computing system about restoring the initial value of power to the second PD and powering down the first PD, as per the command from the external computing system. The method500ends at block520.

Various features as illustrated in the examples described herein may be implemented in a power sourcing equipment (PSE) may perform before an actual swap event of a power supply unit (PSU). For example, the PSE may perform re-negotiating, reduction, and reallocation of the power (PoE) to one or more powered devices (PDs) before the swap event, in order to avoid powering down of those PDs during the actual swap event, and also avoid a time consuming reboot cycle of those devices after the swap event. This will provide more flexibility to customers and less downtime for the PD as more ports will remain up during PSU swap. In other words, the PSE of the present disclosure may prevent downtime in industry or institution networks, which may be very costly. Further, the Type-Length-Value (TLV) added to the LLDP protocol introduces back and forth communication between the PSE and each of the plurality of PDs, and may be customized as a proprietary protocol or may be added to a standard protocol (e.g., IEEE). Further, the present disclosure may be implemented on a multi-slot chassis having multiple ports, as reshuffling of the initial power (PoE) allocated to the one or more PDs is more practical and effective.