74 lines
3.4 KiB
ReStructuredText
74 lines
3.4 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
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Power Sourcing Equipment (PSE) in IEEE 802.3 Standard
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=====================================================
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Overview
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--------
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Power Sourcing Equipment (PSE) is essential in networks for delivering power
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along with data over Ethernet cables. It usually refers to devices like
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switches and hubs that supply power to Powered Devices (PDs) such as IP
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cameras, VoIP phones, and wireless access points.
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PSE vs. PoDL PSE
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----------------
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PSE in the IEEE 802.3 standard generally refers to equipment that provides
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power alongside data over Ethernet cables, typically associated with Power over
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Ethernet (PoE).
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PoDL PSE, or Power over Data Lines PSE, specifically denotes PSEs operating
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with single balanced twisted-pair PHYs, as per Clause 104 of IEEE 802.3. PoDL
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is significant in contexts like automotive and industrial controls where power
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and data delivery over a single pair is advantageous.
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IEEE 802.3-2018 Addendums and Related Clauses
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---------------------------------------------
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Key addenda to the IEEE 802.3-2018 standard relevant to power delivery over
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Ethernet are as follows:
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- **802.3af (Approved in 2003-06-12)**: Known as PoE in the market, detailed in
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Clause 33, delivering up to 15.4W of power.
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- **802.3at (Approved in 2009-09-11)**: Marketed as PoE+, enhancing PoE as
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covered in Clause 33, increasing power delivery to up to 30W.
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- **802.3bt (Approved in 2018-09-27)**: Known as 4PPoE in the market, outlined
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in Clause 33. Type 3 delivers up to 60W, and Type 4 up to 100W.
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- **802.3bu (Approved in 2016-12-07)**: Formerly referred to as PoDL, detailed
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in Clause 104. Introduces Classes 0 - 9. Class 9 PoDL PSE delivers up to ~65W
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Kernel Naming Convention Recommendations
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----------------------------------------
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For clarity and consistency within the Linux kernel's networking subsystem, the
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following naming conventions are recommended:
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- For general PSE (PoE) code, use "c33_pse" key words. For example:
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``enum ethtool_c33_pse_admin_state c33_admin_control;``.
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This aligns with Clause 33, encompassing various PoE forms.
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- For PoDL PSE - specific code, use "podl_pse". For example:
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``enum ethtool_podl_pse_admin_state podl_admin_control;`` to differentiate
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PoDL PSE settings according to Clause 104.
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Summary of Clause 33: Data Terminal Equipment (DTE) Power via Media Dependent Interface (MDI)
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---------------------------------------------------------------------------------------------
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Clause 33 of the IEEE 802.3 standard defines the functional and electrical
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characteristics of Powered Device (PD) and Power Sourcing Equipment (PSE).
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These entities enable power delivery using the same generic cabling as for data
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transmission, integrating power with data communication for devices such as
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10BASE-T, 100BASE-TX, or 1000BASE-T.
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Summary of Clause 104: Power over Data Lines (PoDL) of Single Balanced Twisted-Pair Ethernet
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--------------------------------------------------------------------------------------------
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Clause 104 of the IEEE 802.3 standard delineates the functional and electrical
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characteristics of PoDL Powered Devices (PDs) and PoDL Power Sourcing Equipment
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(PSEs). These are designed for use with single balanced twisted-pair Ethernet
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Physical Layers. In this clause, 'PSE' refers specifically to PoDL PSE, and
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'PD' to PoDL PD. The key intent is to provide devices with a unified interface
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for both data and the power required to process this data over a single
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balanced twisted-pair Ethernet connection.
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