1.. SPDX-License-Identifier: GPL-2.0 2 3Power Sourcing Equipment (PSE) in IEEE 802.3 Standard 4===================================================== 5 6Overview 7-------- 8 9Power Sourcing Equipment (PSE) is essential in networks for delivering power 10along with data over Ethernet cables. It usually refers to devices like 11switches and hubs that supply power to Powered Devices (PDs) such as IP 12cameras, VoIP phones, and wireless access points. 13 14PSE vs. PoDL PSE 15---------------- 16 17PSE in the IEEE 802.3 standard generally refers to equipment that provides 18power alongside data over Ethernet cables, typically associated with Power over 19Ethernet (PoE). 20 21PoDL PSE, or Power over Data Lines PSE, specifically denotes PSEs operating 22with single balanced twisted-pair PHYs, as per Clause 104 of IEEE 802.3. PoDL 23is significant in contexts like automotive and industrial controls where power 24and data delivery over a single pair is advantageous. 25 26IEEE 802.3-2018 Addendums and Related Clauses 27--------------------------------------------- 28 29Key addenda to the IEEE 802.3-2018 standard relevant to power delivery over 30Ethernet are as follows: 31 32- **802.3af (Approved in 2003-06-12)**: Known as PoE in the market, detailed in 33 Clause 33, delivering up to 15.4W of power. 34- **802.3at (Approved in 2009-09-11)**: Marketed as PoE+, enhancing PoE as 35 covered in Clause 33, increasing power delivery to up to 30W. 36- **802.3bt (Approved in 2018-09-27)**: Known as 4PPoE in the market, outlined 37 in Clause 33. Type 3 delivers up to 60W, and Type 4 up to 100W. 38- **802.3bu (Approved in 2016-12-07)**: Formerly referred to as PoDL, detailed 39 in Clause 104. Introduces Classes 0 - 9. Class 9 PoDL PSE delivers up to ~65W 40 41Kernel Naming Convention Recommendations 42---------------------------------------- 43 44For clarity and consistency within the Linux kernel's networking subsystem, the 45following naming conventions are recommended: 46 47- For general PSE (PoE) code, use "c33_pse" key words. For example: 48 ``enum ethtool_c33_pse_admin_state c33_admin_control;``. 49 This aligns with Clause 33, encompassing various PoE forms. 50 51- For PoDL PSE - specific code, use "podl_pse". For example: 52 ``enum ethtool_podl_pse_admin_state podl_admin_control;`` to differentiate 53 PoDL PSE settings according to Clause 104. 54 55Summary of Clause 33: Data Terminal Equipment (DTE) Power via Media Dependent Interface (MDI) 56--------------------------------------------------------------------------------------------- 57 58Clause 33 of the IEEE 802.3 standard defines the functional and electrical 59characteristics of Powered Device (PD) and Power Sourcing Equipment (PSE). 60These entities enable power delivery using the same generic cabling as for data 61transmission, integrating power with data communication for devices such as 6210BASE-T, 100BASE-TX, or 1000BASE-T. 63 64Summary of Clause 104: Power over Data Lines (PoDL) of Single Balanced Twisted-Pair Ethernet 65-------------------------------------------------------------------------------------------- 66 67Clause 104 of the IEEE 802.3 standard delineates the functional and electrical 68characteristics of PoDL Powered Devices (PDs) and PoDL Power Sourcing Equipment 69(PSEs). These are designed for use with single balanced twisted-pair Ethernet 70Physical Layers. In this clause, 'PSE' refers specifically to PoDL PSE, and 71'PD' to PoDL PD. The key intent is to provide devices with a unified interface 72for both data and the power required to process this data over a single 73balanced twisted-pair Ethernet connection. 74