Design And Research Of PoE Management System Based On IEEE 802.3at Standard

With the widely application of the Internet and IoT(Internet of Things), intelligent life and intelligence office based on all kinds of intelligent network terminal equipments gradually appeared in our life, and with the increase of the intelligent terminal equipments, they encountered problems in power supply and management mode.The traditional power supply mode is to install a socket and a DC power supply next to the terminal equipment, which causes great security risks and large power loss; the traditional ways of management are maintained by specialized network administrators individually, which increases the manpower cost. In order to improve the situation, the power over Ethernet technology, PoE (Power over Ethernet) technology, is proposed to provide DC power supply for terminal equipments when transmitting network signals through the Ethernet network cable at the same time, in the end to achieve "transporting DC power and net signals through a single cable". We can also make full use of PoE technology for unified management and maintenance of intelligent terminal equipments.With the adoption of the PoE technology, a wide variety of PoE devices (including power source Ethernet and powered device) begin to appear in the market.In order to unified the using standards of Poe device, IEEE established Poe special working group, and announced the development of the IEEE 802.3af standard in 2003, in which each port can provide maximum 13W power. Poe began to flourish in the market.With the increase of the power consumption of the network terminal equipment, Poe standards need to be improved, so Poe special working group released a new standard IEEE 802.3at (downward compatible with IEEE 802.3af) in 2009, the standard stipulates that each port can provide up to 30W power, which is the most common standard application in the PoE technology market. But it is not enough to meet the needs of Poe device development. Therefore, in this paper it is based on Ethernet switches and Poe hardware modules in Poe technology and developed a software system up to 60W maximum power. The system can not only supply power for switches with PD (powered device) of different power requirements attached, but also unify management and maintenance.This paper mainly completed the following aspects:1. In the paper it describes the development and application of PoE technology at home and abroad and summarizes the development direction of the future PoE technology, then presents the design requirements and design goals of the system according to the actual needs of the scene.2. Based on Embedded Linux system to design system hardware, it selects appropriate PSE (power Source Ethernet) power management chip, and the reasonable way of power supply as well as Poe module design pattern according to the features of Poe technology and design requirements.3. After analyzing the overall software design of the PoE system, the main parts are divided into driven design and equipment management, in which equipment management is the research focus.4. The paper is to carry on the detailed analysis and design of the key modules in the equipment management software. It mainly includes:inspection management of the PD equipment, power management the PD equipment, PSE port status reporting, chip communication testing, power supply management time, main control board and interface board communication, among which power management is the core part of the software. This paper proposes a reasonable power allocation scheme and the design of power software management.5. The PoE system uses SNMP (Simple Gateway Protocol) and the Web terminal of the PD equipment for monitoring and management to realize the entire intelligent management of PoE system.The design and research results in this paper have been successfully applied to a variety of switches and routers by a communications equipment manufacturer. It has achieved good results and economic benefits in the practical application.