1 .. SPDX-License-Identifier: GPL-2.0 1 .. SPDX-License-Identifier: GPL-2.0
2 2
3 Power Sourcing Equipment (PSE) in IEEE 802.3 S 3 Power Sourcing Equipment (PSE) in IEEE 802.3 Standard
4 ============================================== 4 =====================================================
5 5
6 Overview 6 Overview
7 -------- 7 --------
8 8
9 Power Sourcing Equipment (PSE) is essential in 9 Power Sourcing Equipment (PSE) is essential in networks for delivering power
10 along with data over Ethernet cables. It usual 10 along with data over Ethernet cables. It usually refers to devices like
11 switches and hubs that supply power to Powered 11 switches and hubs that supply power to Powered Devices (PDs) such as IP
12 cameras, VoIP phones, and wireless access poin 12 cameras, VoIP phones, and wireless access points.
13 13
14 PSE vs. PoDL PSE 14 PSE vs. PoDL PSE
15 ---------------- 15 ----------------
16 16
17 PSE in the IEEE 802.3 standard generally refer 17 PSE in the IEEE 802.3 standard generally refers to equipment that provides
18 power alongside data over Ethernet cables, typ 18 power alongside data over Ethernet cables, typically associated with Power over
19 Ethernet (PoE). 19 Ethernet (PoE).
20 20
21 PoDL PSE, or Power over Data Lines PSE, specif 21 PoDL PSE, or Power over Data Lines PSE, specifically denotes PSEs operating
22 with single balanced twisted-pair PHYs, as per 22 with single balanced twisted-pair PHYs, as per Clause 104 of IEEE 802.3. PoDL
23 is significant in contexts like automotive and 23 is significant in contexts like automotive and industrial controls where power
24 and data delivery over a single pair is advant 24 and data delivery over a single pair is advantageous.
25 25
26 IEEE 802.3-2018 Addendums and Related Clauses 26 IEEE 802.3-2018 Addendums and Related Clauses
27 --------------------------------------------- 27 ---------------------------------------------
28 28
29 Key addenda to the IEEE 802.3-2018 standard re 29 Key addenda to the IEEE 802.3-2018 standard relevant to power delivery over
30 Ethernet are as follows: 30 Ethernet are as follows:
31 31
32 - **802.3af (Approved in 2003-06-12)**: Known 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. 33 Clause 33, delivering up to 15.4W of power.
34 - **802.3at (Approved in 2009-09-11)**: Market 34 - **802.3at (Approved in 2009-09-11)**: Marketed as PoE+, enhancing PoE as
35 covered in Clause 33, increasing power deliv 35 covered in Clause 33, increasing power delivery to up to 30W.
36 - **802.3bt (Approved in 2018-09-27)**: Known 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 37 in Clause 33. Type 3 delivers up to 60W, and Type 4 up to 100W.
38 - **802.3bu (Approved in 2016-12-07)**: Former 38 - **802.3bu (Approved in 2016-12-07)**: Formerly referred to as PoDL, detailed
39 in Clause 104. Introduces Classes 0 - 9. Cla 39 in Clause 104. Introduces Classes 0 - 9. Class 9 PoDL PSE delivers up to ~65W
40 40
41 Kernel Naming Convention Recommendations 41 Kernel Naming Convention Recommendations
42 ---------------------------------------- 42 ----------------------------------------
43 43
44 For clarity and consistency within the Linux k 44 For clarity and consistency within the Linux kernel's networking subsystem, the
45 following naming conventions are recommended: 45 following naming conventions are recommended:
46 46
47 - For general PSE (PoE) code, use "c33_pse" ke 47 - For general PSE (PoE) code, use "c33_pse" key words. For example:
48 ``enum ethtool_c33_pse_admin_state c33_admin 48 ``enum ethtool_c33_pse_admin_state c33_admin_control;``.
49 This aligns with Clause 33, encompassing var 49 This aligns with Clause 33, encompassing various PoE forms.
50 50
51 - For PoDL PSE - specific code, use "podl_pse" 51 - For PoDL PSE - specific code, use "podl_pse". For example:
52 ``enum ethtool_podl_pse_admin_state podl_adm 52 ``enum ethtool_podl_pse_admin_state podl_admin_control;`` to differentiate
53 PoDL PSE settings according to Clause 104. 53 PoDL PSE settings according to Clause 104.
54 54
55 Summary of Clause 33: Data Terminal Equipment 55 Summary of Clause 33: Data Terminal Equipment (DTE) Power via Media Dependent Interface (MDI)
56 ---------------------------------------------- 56 ---------------------------------------------------------------------------------------------
57 57
58 Clause 33 of the IEEE 802.3 standard defines t 58 Clause 33 of the IEEE 802.3 standard defines the functional and electrical
59 characteristics of Powered Device (PD) and Pow 59 characteristics of Powered Device (PD) and Power Sourcing Equipment (PSE).
60 These entities enable power delivery using the 60 These entities enable power delivery using the same generic cabling as for data
61 transmission, integrating power with data comm 61 transmission, integrating power with data communication for devices such as
62 10BASE-T, 100BASE-TX, or 1000BASE-T. 62 10BASE-T, 100BASE-TX, or 1000BASE-T.
63 63
64 Summary of Clause 104: Power over Data Lines ( 64 Summary of Clause 104: Power over Data Lines (PoDL) of Single Balanced Twisted-Pair Ethernet
65 ---------------------------------------------- 65 --------------------------------------------------------------------------------------------
66 66
67 Clause 104 of the IEEE 802.3 standard delineat 67 Clause 104 of the IEEE 802.3 standard delineates the functional and electrical
68 characteristics of PoDL Powered Devices (PDs) 68 characteristics of PoDL Powered Devices (PDs) and PoDL Power Sourcing Equipment
69 (PSEs). These are designed for use with single 69 (PSEs). These are designed for use with single balanced twisted-pair Ethernet
70 Physical Layers. In this clause, 'PSE' refers 70 Physical Layers. In this clause, 'PSE' refers specifically to PoDL PSE, and
71 'PD' to PoDL PD. The key intent is to provide 71 'PD' to PoDL PD. The key intent is to provide devices with a unified interface
72 for both data and the power required to proces 72 for both data and the power required to process this data over a single
73 balanced twisted-pair Ethernet connection. 73 balanced twisted-pair Ethernet connection.
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