WO2016116022A1

WO2016116022A1 - Method and device for detecting overcurrent of power over ethernet

Info

Publication number: WO2016116022A1
Application number: PCT/CN2016/071224
Authority: WO
Inventors: 程宁; 董伟杰; 王欣
Original assignee: 中兴通讯股份有限公司
Priority date: 2015-01-23
Filing date: 2016-01-18
Publication date: 2016-07-28
Also published as: CN105871579B; CN105871579A

Abstract

Disclosed are a method and a device for detecting overcurrent of power over Ethernet, comprising: detecting a current state of each pair of twisted-pair line pairs in Ethernet cables in a power over Ethernet system; and when current states of one or more pairs of twisted-pair line pairs are abnormal, controlling the power over Ethernet (PoE).

Description

Method and device for detecting power overcurrent in Ethernet

Technical field

This application relates to, but is not limited to, the field of Power Over Ethernet (PoE).

Background technique

PoE refers to the transmission of data for some IP (Internet Protocol)-based terminals (such as IP phones, WLAN access points APs, network cameras, etc.) in the case of the Ethernet Cat.5 cabling infrastructure. At the same time, the signal can also provide DC power supply technology for such devices. The standard used for PoE Power over Ethernet is IEEE 802.3af. PoE+ is an enhanced version of PoE Power over Ethernet. It defines a device with a power requirement higher than 12.95W as Class 4 (this level is described in IEEE 802.3af, but reserved for future use), which extends the power level to 25W or higher.

A complete PoE system consists of two parts: Power Sourcing Equipment (PSE) and Powered Device (PD). For the new generation of high-power PoE applications, including long-distance wireless access points (WAP, Wireless) Access Point), thin client and thermal monitoring camera applications have required more power. At present, multiple vendor solutions can realize mutual recognition of PSE and PD and provide up to 90W of power for PD.

In a 90W power PoE application, the current of the entire loop is 2.2A at the maximum, and the 4 pairs of twisted pairs of the CAT5e type network cable are simultaneously powered. The average current on each pair is 1.1A, and the engineering needs to be less than Bundling of 25 network cables.

Most PoE chips work in automatic mode, with overcurrent and short circuit detection functions, which can automatically stop power supply during overcurrent and short circuit. For the single PSE controller of Figure 1, the 48W power PoE powered by 4 pairs of twisted pairs In the application, the 4 twisted pair power supply mode uses the network cable 1, 2 and the network cable 4, 5 pairs directly connected together as the PSE positive terminal, and the network cable 3, 6 and the network cable 7 and 8 pairs are directly connected together as the PSE negative terminal. powered by. If there is a broken or broken circuit in a twisted pair, for example, the network cable 4, 5 or the network cable 7 and 8 line pairs are broken and broken, the network cable 1, 2 / network cable 3, 6 line pair is normal, or the network cable 1, 2 or network cable 3, 6 pairs of broken breaks, network cable 4, 5 / network cable 7, 8 pairs are normal, PoE PSE chip detection of the entire loop current value is unchanged, PSE chip The overcurrent protection function is not triggered, but the current output by PoE is concentrated by two twisted pairs to one twisted pair, resulting in a maximum of 2.2A for a twisted pair transmission, far exceeding the maximum CAT5e type network cable. The flow capacity has huge potential risks.

The maximum flow capacity of the CAT5e type network cable is 1.2A. Since the cable is usually twisted into a cable bundle and placed in the wiring closet, if the transmission current exceeds the maximum value, the heat dissipation problem of the cable bundle can easily lead to fire, deflagration, etc. The accident happened. At the same time, the damaged network cable also has the danger of leakage, and the uncertainty of the cable fault location greatly increases the difficulty for the user to troubleshoot the cable.

Summary of the invention

The following is an overview of the topics detailed in this document. This Summary is not intended to limit the scope of the claims.

This paper provides a method and device for over-current detection of Ethernet power supply, which can detect the abnormality and risk caused by network cable breakage during high-power PoE power supply and avoid accidents.

A method for Ethernet power overcurrent detection includes:

Detecting the current state of each pair of twisted pair pairs in the Ethernet line in the Power over Ethernet system;

When the current state of the pair or pairs of twisted pairs is abnormal, the Power over Ethernet PoE is controlled.

Optionally, detecting the current state of each pair of twisted pair pairs in the Ethernet line in the Power over Ethernet system includes:

The current state of the pair is determined by monitoring the state of the corresponding network port of the twisted pair.

Monitoring the state of the corresponding network port of the twisted pair, and determining the pair of pairs in the power supply when the network port is in the Gigabit mode and the PoE power is normal. The current status is normal;

When the state of the network port is changed from the Gigabit electrical port mode to the 100 Mbps electrical port mode, or the Gigabit electrical port mode is changed to the ten mega electrical port mode, the power supply status of the PoE is detected:

When the power supply device fails to supply power, determining that the current state of the pair is abnormal;

When the power supply device is powered normally, the connection of the network port is interrupted, and the network cable detection tool integrated by the physical layer chip is used to detect the network cable status of the twisted pair.

Optionally, detecting a current state of each pair of twisted pair in the Ethernet line in the power supply system includes: monitoring a state of the network port corresponding to the pair of twisted pairs, when the network port is located The state is a 100 Mbps electrical port or a 10 megabit electrical port mode, and when the PoE power supply state is normal, the idle line pair is switched to another physical layer chip, and the network layer of the idle line pair of the network layer detection tool integrated by the physical layer chip is used;

Monitoring the status of the network port, if the connection of the network port fails, interrupting the connection of the network port, and detecting the state of the signal line pair by using a network line detection tool integrated by the physical layer chip;

The idle line pair only bears PoE power supply when the state of the network port is 100 Mbps or 10 Mbps;

The signal line pair transmits both signals and PoE power when the state of the network port is 100 Mbps or 10 Mbps.

A device for power overcurrent detection of a power supply, comprising:

The detecting module is configured to: detect a current state of each pair of twisted pair pairs in the Ethernet line in the Ethernet power supply system;

The control module is configured to: when the current state of the pair or pairs of twisted pairs is abnormal, control PoE power supply.

Optionally, the detecting module is configured to: determine a current state of the pair by monitoring a state of the corresponding network port of the twisted pair.

Optionally, the detecting module comprises:

The network port monitoring unit is configured to: monitor a state of the network port corresponding to the twisted pair;

The first determining unit is configured to: determine a state in which the network port is located;

The power supply monitoring unit is configured to: when the state of the network port is changed from a Gigabit electrical port mode to a 100M electrical port mode, or a Gigabit electrical port mode is changed to a ten-mega electrical port mode, detecting the PoE Power supply status;

The second determining unit is configured to: determine the power supply state of the power supply device,

Determining a unit, configured to: determine a current state of the pair;

The interrupting unit is configured to: when the state of the network port is changed from the Gigabit electrical port mode to the 100M electrical port mode, or the Gigabit electrical port mode is changed to the ten-mega electrical port mode, the power supply device supplies power. Normally, the connection of the network port is interrupted;

The network cable monitoring unit is configured to: when the connection of the network port is interrupted, use a network layer detection tool integrated by the physical layer chip to detect the network cable state of the twisted pair.

Optionally, the detecting module further includes a modifying unit;

The interruption unit is further configured to: when the state of the network port is 100 Mbps or 10 Mbps, and the PoE power supply status is normal, when the network port connection fails, the network port is disconnected. ;

The network cable monitoring unit is further configured to: detect the state of the signal pair by using a network layer detecting tool integrated by a physical layer chip;

The modifying unit is configured to: switch the idle pair to another physical layer chip when the state of the network port is 100 Mbps or 10 Mbps;

The network cable monitoring unit is further configured to: detect a network cable state of an idle pair by using a network layer detection tool integrated by a physical layer of the port;

The idle line pair only bears PoE power supply when the state of the network port is 100 Mbps or 10 Mbps.

A computer readable storage medium storing computer executable instructions for performing the method of any of the above.

Compared with the related art, the detecting method and device of the embodiment of the present invention do not affect the use of the normal service, and the normal data transmission and the PoE power supply do not interrupt the service, and the network cable can be detected in a short time by the above means. Fault, real-time is very strong, by stopping PoE power supply, ensuring the whole The security of the PoE power supply can also obtain the fault information of the network cable, which is helpful for the maintenance of the network cable fault. The abnormality and risk caused by the damage of the network cable generated during the power supply of the high-power PoE can detect the abnormality and take corresponding measures in time. Avoid accidents.

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

BRIEF abstract

1 is a schematic diagram of a single PSE high-capacity PoE power supply according to the related art;

2 is a flowchart of a method for detecting power overcurrent detection of a power supply according to an embodiment of the present invention;

3 is a schematic structural diagram of an apparatus for detecting over-current of a power supply over Ethernet according to an embodiment of the present invention;

4 is a schematic diagram of cable detection according to an embodiment of the present invention;

FIG. 5 is a flowchart of a method for detecting over-current over Ethernet power according to Embodiment 1 of the present invention; FIG.

FIG. 6 is a block diagram of detection when the state of the network port is 100BASE-TX or 10BASE-T according to the first embodiment of the present invention.

Embodiments of the invention

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments in the present application may be arbitrarily combined with each other.

As shown in FIG. 2, a method for detecting a power overcurrent detection of a power supply provided by an embodiment of the present invention includes:

Step 201: Detect a current state of each pair of twisted pair pairs in the Ethernet line in the Ethernet power supply system.

Step 202: Control the Power over Ethernet PoE when the current state of the pair or pairs of twisted pair pairs is abnormal.

The current state of each pair of twisted pair pairs in the Ethernet line in the Ethernet power supply system is detected:

When the power supply device is powered normally, the connection of the network port is interrupted, and the network cable detection tool integrated by the physical layer chip is used to detect the network cable status of the twisted pair;

When the state of the network port is 100 Mbps or 10 Mbps, and the PoE power supply status is normal, the idle line pair is switched to another physical layer chip, and the physical layer chip integrated network line detection tool is adopted. The status of the network cable of the idle pair;

And monitoring the status of the network port. If the network port connection fails, the connection of the network port is interrupted, and the network line detection tool integrated by the physical layer chip is used to detect the status of the signal line pair;

In the embodiment of the present invention, when a single PSE controller is used, when a large-capacity PoE of four pairs of twisted pairs is powered, the network cable is abnormal and the risk of over-current of the network cable is reduced. The method does not change the existing Ethernet cabling and affects the existing services. By monitoring the status of the network port, the network cable detection tool integrated with the PHY (Port Physical Layer) is used to detect the fault of the network cable in time. The power supply is controlled to effectively reduce the risk caused by over-current of the network cable.

The method of the embodiment of the present invention further includes:

Report a cable fault alarm.

If the initial state of the network port is 1000BASE-TX, the processor of the device where the network port is located periodically queries the status of the network port, once the network port is used. If the status is changed to 100BASE-TX or 10BASE-T, the PoE power supply status is detected in real time. If the power supply fails, the network cable is faulty and the cable fault alarm is reported. If the power supply is still normal, the LINK connection of the network port is interrupted and the network cable is detected. The tool detects the network cable. If a fault is found, the PoE power is turned off and the cable fault alarm is reported.

Further, when the network port status is 100BASE-TX or 10BASE-T, the data is transmitted by the network cable 1, 2/network cable 3, 6 pairs, and the large-capacity PoE power supply uses 4 pairs of twisted pair output currents, and the power supply is normal.

Since the cable diagnostic function of the PHY is to operate four pairs of wires at the same time, cable diagnosis cannot be performed on one pair. If the cable is diagnosed in the state of 100BASE-TX or 10BASE-T, the cable is diagnosed for four pairs. The function will cause LINK interruption and affect normal business.

Therefore, the idle line pair of the data transmission in this case - the network line 4, 5 / network line 7, 8 line pair is switched to another 100 Mbps PHY, this PHY does not undertake the task of data transmission, by the device of the network port The processor runs a network cable detection tool to periodically detect the state of the network cable 4, 5/network cable 7 and 8 pairs of the 100 Mbps PHY connection. If a fault is found, the PoE power supply is turned off, and the cable fault alarm is reported;

At the same time, the network cable 1, 2/network cable 3, 6 line pairs continue to bear data transmission. Once the network port LINK fails, the network port is dropped, the PoE power supply is turned off, the network cable detection tool is run, and if the network cable is found to have problems, the report line is sent. Cable failure alarm;

Further, when the status of the network port is maintained at 1000BASE-TX, since the data is normally transmitted on the four pairs of twisted pairs, the network cable can be considered as no problem.

As shown in FIG. 3, an embodiment of the present invention provides a device for detecting over-current of a power over Ethernet, including:

The detecting module 31 is configured to: detect a current state of each pair of twisted pair pairs in the Ethernet line in the Ethernet power supply system;

The control module 32 is configured to control PoE power supply when the current state of the pair or pairs of twisted pair is abnormal.

Optionally, the detecting module 31 is configured to determine a current state of the pair by monitoring a state of the corresponding network port of the twisted pair.

The detecting module 31 includes:

The network port monitoring unit 311 is configured to: monitor a state in which the network port corresponding to the twisted pair is located;

The first determining unit 312 is configured to: determine a state in which the network port is located;

The power monitoring unit 313 is configured to detect the PoE when the state of the network port is changed from the Gigabit electrical port mode to the 100 Mbps electrical port mode, or the Gigabit electrical port mode is changed to the ten mega electrical port mode. Power supply status;

The second determining unit 314 is configured to: determine the power supply status of the power supply end device,

a determining unit 315, configured to: determine a current state of the pair;

The interrupting unit 316 is configured to: when the state of the network port is changed from the Gigabit electrical port mode to the 100 Mbps electrical port mode, or the Gigabit electrical port mode is changed to the ten mega electrical port mode, the power supply terminal device When the power supply is normal, the connection of the network port is interrupted;

The interrupting unit 316 is further configured to: when the state of the network port is 100 Mbps or 10 Mbps, and the PoE power supply is normal, when the network port connection fails, the network port is disconnected;

The network cable monitoring unit 317 is configured to: when the connection of the network port is interrupted, the network line detection tool integrated by the physical layer chip is used to detect the state of the signal line pair; and at the same time, it is also set to: the physical layer integrated network line detection using the port The tool detects the state of the network cable of the idle pair;

The modifying unit 318 is configured to: when the network port status is a 100 Mbps electrical port or a ten mega electrical port, switch the idle pair to another physical layer chip;

The device may further include: an alarm module 33, configured to: report a cable failure alarm.

Embodiment 1

Currently, the PHY chip itself has cable diagnostics. Although it is not required in IEEE 802.3-2012, most PHYs support cable diagnostics. Cable diagnostic tools are integrated into the PHY to help customers diagnose cable problems. The diagnostic function can measure the length of each pair of pairs on the network cable, and can diagnose the short-circuit or open-circuit status of each pair of twisted pairs to determine the discontinuous location.

In this embodiment, the network port LINK negotiation is 1000BASE-TX, which can be run without affecting the service and LINK status; for the network port LINK negotiation is 100BASE-TX or 10BASE-T, since each operation is for 4 lines. The operation cable diagnostic function for simultaneous operation will cause the LINK to be disconnected. Once the diagnosis is completed, the LINK status will be re-established;

As shown in Figure 4, the length of the four pairs of twisted pairs can be detected and recorded by the cable detection tool. At the same time, the short circuit or open state of each pair of twisted pairs can be diagnosed to determine the discontinuous location.

When the large-capacity PoE is powered, the data line and the DC power supply are transmitted simultaneously on the Ethernet line. The Gigabit Ethernet port uses 4 pairs of twisted pair to transmit signals, and the 100M network port uses 2 pairs of twisted pair to transmit signals. High-power PoE power supply needs to be adopted. 4 power is supplied to the twisted pair.

Once the network cable fails, it will directly affect the status and transmission rate of the network port and PoE power supply. The processor of the device where the network port is located can monitor the connection status and rate of the network port in real time by reading the PHY register. The PoE power supply state is obtained by reading the registers of the PoE power supply control chip. Therefore, the above information can be combined to analyze whether the network cable is faulty, and then determine whether there is a risk of excessive output current on the network cable. Once the PoE output current is found to be too large, the processor of the device can operate the register of the PoE power supply control chip. Turn off PoE power.

If the initial state of the network port is 1000BASE-TX, the status of the network port is 1000 A-TX. In this case, the status is A in Figure 5, and the network port is monitored. Status, once the status of the network port is changed to 100BASE-TX or 10BASE-T, the PoE power supply status is detected in real time. If the power supply fails, the PoE power supply is actively interrupted, and the power failure alarm is reported. At the same time, the LINK connection of the network port is interrupted, and the network cable detection tool is run. Detect 4 pairs of twisted pairs. If the network cable is faulty, report the network cable fault alarm.

If the power supply is still normal, there may be a problem with the network cable 4, 5/network cable 7 and 8 pairs. The PoE power supply outputs current through the network cable 1, 2/network cable 3, 6 pairs. At this time, the LINK connection of the network port should be interrupted immediately. Run the network cable detection tool to detect the network cable of the network cable 4, 5/network cable 7 and 8 pairs. Once the fault is found, the PoE power supply is turned off, and the network cable fault alarm is reported; if there is no problem, it jumps to the state B in the figure;

When the network port status is 1000BASE-TX, when the network port status is normal, the data is normally transmitted due to the 4 twisted pairs. It can be considered that there is no problem with the network cable. After the normal power supply, the PoE chip monitors whether the current is overcurrent or not. When the network port LINK fails, the network port is disconnected, the PoE is powered off, and the network cable detection tool is run. If the network cable is faulty, the cable fault alarm is reported.

When the network port status is negotiated as 100BASE-TX or 10BASE-T, corresponding to the state B in FIG. 5, the data transmission uses only the network cable 1, 2/network cable 3, and 6 line pairs. For a single PSE controller, a large-capacity PoE application uses four pairs of twisted-pair power cables. If there is a problem with the network cable 4, 5/network cable 7, 8 pairs, the data transmission and PoE power supply can still be maintained, but at this time, the network cable 1 and 2 / The network line 3, 6 line pair current will increase sharply. Therefore, in this case, it is necessary to detect whether there is a problem in the line pair 4, 5/network line 7 and 8 line pairs in real time without affecting the service.

Since the cable diagnostic function of each PHY is operated simultaneously for 4 pairs, the cable diagnosis of the network cable 4, 5/network cable 7 and 8 pairs cannot be performed separately, and if the state is 100BASE-TX or 10BASE-T. The operation of the cable diagnostic function on the four pairs will cause the LINK to be interrupted and affect normal services.

Therefore, the network cable 4, 5/network cable 7, 8 in this case is switched by the processor to another 100 Mbps PHY through the electronic switch, and the PHY does not undertake the task of data transmission, and is processed by the device where the network port is located. The device runs a network cable detection tool to periodically query the status of the network cable 4, 5/network cable 7 and 8 pairs of the 100 Mbps PHY connection, and if the fault is found, the PoE power supply is turned off;

At the same time, the network cable 1, 2/network cable 3, 6 line pairs serve as the channel for transmitting data on the network port. Once the network port is dropped, the LINK fails, the processor turns off the PoE power supply, runs the network cable detection tool, and detects the network cable 1, 2/network cable. 3, 6 line pair status, once the fault is found, the cable fault alarm is reported; the block diagram is shown in Figure 6.

One of ordinary skill in the art will appreciate that all or a portion of the steps of the above-described embodiments can be implemented using a computer program flow, which can be stored in a computer readable storage medium, such as on a corresponding hardware platform (eg, The system, device, device, device, etc. are executed, and when executed, include one or a combination of the steps of the method embodiments.

Optionally, all or part of the steps of the foregoing embodiments may also be implemented by using an integrated circuit, and the steps may be separately fabricated into integrated circuit modules, or multiple modules thereof or The steps are made into a single integrated circuit module.

The devices/function modules/functional units in the above embodiments may be implemented by a general-purpose computing device, which may be centralized on a single computing device or distributed over a network of multiple computing devices.

When the device/function module/functional unit in the above embodiment is implemented in the form of a software function module and sold or used as a stand-alone product, it can be stored in a computer readable storage medium. The above mentioned computer readable storage medium may be a read only memory, a magnetic disk or an optical disk or the like.

Industrial applicability

The detection method and device of the embodiment of the present invention do not affect the use of the normal service, and the normal data transmission and the PoE power supply do not interrupt the service, and the network cable fault can be detected in a short time, and the real-time performance is strong, and the PoE is suspended. Power supply ensures the safety of the entire PoE power supply; at the same time, it can also obtain the fault information of the network cable, which is helpful for the maintenance of the network cable fault. The abnormality and risk caused by the damage of the network cable generated during the power supply of the high-power PoE can detect the abnormality and take corresponding measures in time. Measures to avoid accidents.

Claims

A method for Ethernet power overcurrent detection includes:

Detecting the current state of each pair of twisted pair pairs in the Ethernet line in the Power over Ethernet system;

When the current state of the pair or pairs of twisted pairs is abnormal, the Power over Ethernet PoE is controlled.
The method of claim 1 wherein detecting the current state of each pair of twisted pair pairs in the Ethernet line in the Power over Ethernet system comprises:

The current state of the pair is determined by monitoring the state of the corresponding network port of the twisted pair.
The method of claim 2 wherein detecting the current state of each pair of twisted pair pairs in the Ethernet line in the Power over Ethernet system comprises:

Monitoring the state of the corresponding network port of the twisted pair, and determining the pair of pairs in the power supply when the network port is in the Gigabit mode and the PoE power is normal. The current status is normal;

When the state of the network port is changed from the Gigabit electrical port mode to the 100 Mbps electrical port mode, or the Gigabit electrical port mode is changed to the ten mega electrical port mode, the power supply status of the PoE is detected:

When the power supply device fails to supply power, determining that the current state of the pair is abnormal;

When the power supply device is powered normally, the connection of the network port is interrupted, and the network cable detection tool integrated by the physical layer chip is used to detect the network cable status of the twisted pair.
The method of claim 2, wherein detecting a current state of each pair of twisted pair pairs in the Ethernet line in the power over Ethernet system comprises: monitoring a state of the network port corresponding to the pair of twisted pairs, when The state of the network port is 100 Mbps or 10 Mbps, and when the PoE power supply status is normal, the idle line pair is switched to another physical layer chip, and the network layer detection tool integrated by the physical layer chip is idle. The network cable status of the pair;

Monitoring the status of the network port, if the connection of the network port fails, interrupting the connection of the network port, and detecting the state of the signal line pair by using a network line detection tool integrated by the physical layer chip;

The state of the idle line pair in the network port is a 100M electrical port mode or a 10 M electrical port mode. Only bear PoE power supply;

The signal line pair transmits both signals and PoE power when the state of the network port is 100 Mbps or 10 Mbps.
A device for power overcurrent detection of a power supply, comprising:

The detecting module is configured to: detect a current state of each pair of twisted pair pairs in the Ethernet line in the Ethernet power supply system;

The control module is configured to: when the current state of the pair or pairs of twisted pairs is abnormal, control PoE power supply.
The device according to claim 5, wherein the detecting module is configured to determine a current state of the pair by monitoring a state of the corresponding network port of the twisted pair.
The apparatus of claim 6 wherein the detecting module comprises:

The network port monitoring unit is configured to: monitor a state of the network port corresponding to the twisted pair;

The first determining unit is configured to: determine a state in which the network port is located;

The power supply monitoring unit is configured to: when the state of the network port is changed from a Gigabit electrical port mode to a 100M electrical port mode, or a Gigabit electrical port mode is changed to a ten-mega electrical port mode, detecting the PoE Power supply status;

The second determining unit is configured to: determine the power supply state of the power supply device,

Determining a unit, configured to: determine a current state of the pair;

The interrupting unit is configured to: when the state of the network port is changed from the Gigabit electrical port mode to the 100M electrical port mode, or the Gigabit electrical port mode is changed to the ten-mega electrical port mode, the power supply device supplies power. Normally, the connection of the network port is interrupted;

The network cable monitoring unit is configured to: when the connection of the network port is interrupted, use a network layer detection tool integrated by the physical layer chip to detect the network cable state of the twisted pair.
The apparatus according to claim 7, wherein the detecting module further comprises: a modifying unit;

The interruption unit is further configured to: when the state of the network port is 100 Mbps or 10 Mbps, and the PoE power supply status is normal, when the network port connection fails, the network port is disconnected. ;

The network cable monitoring unit is further configured to: detect the state of the signal pair by using a network layer detecting tool integrated by a physical layer chip;

The modifying unit is configured to: switch the idle pair to another physical layer chip when the state of the network port is 100 Mbps or 10 Mbps;

The network cable monitoring unit is further configured to: detect a network cable state of an idle pair by using a network layer detection tool integrated by a physical layer of the port;

The idle line pair only bears PoE power supply when the state of the network port is 100 Mbps or 10 Mbps;

The signal line pair transmits both signals and PoE power when the state of the network port is 100 Mbps or 10 Mbps.
A computer readable storage medium storing computer executable instructions for performing the method of any of claims 1-4.