Lines Matching +full:ethernet +full:- +full:pse
1 .. SPDX-License-Identifier: GPL-2.0
3 PSE Power Interface (PSE PI) Documentation
6 The Power Sourcing Equipment Power Interface (PSE PI) plays a pivotal role in
7 the architecture of Power over Ethernet (PoE) systems. It is essentially a
9 eight-pin modular jack, commonly known as the Ethernet RJ45 port. This
11 over Ethernet cables.
14 ---------------------------
16 The IEEE 802.3 standard provides detailed documentation on the PSE PI.
19 - Section "33.2.3 PI pin assignments" covers the pin assignments for PoE
21 - Section "145.2.4 PSE PI" addresses the configuration for PoE systems that
22 deliver power over all four pairs of an Ethernet cable.
24 PSE PI and Single Pair Ethernet
25 -------------------------------
27 Single Pair Ethernet (SPE) represents a different approach to Ethernet
29 transmission. Unlike the configurations detailed in the PSE PI for standard
30 Ethernet, which can involve multiple power sourcing arrangements across four or
31 two pairs of wires, SPE operates on a simpler model due to its single-pair
33 assignments for power delivery, as described in the PSE PI for multi-pair
34 Ethernet, are not applicable to SPE.
36 Understanding PSE PI
37 --------------------
39 The Power Sourcing Equipment Power Interface (PSE PI) is a framework defining
40 how Power Sourcing Equipment (PSE) delivers power to Powered Devices (PDs) over
41 Ethernet cables. It details two main configurations for power delivery, known
47 ----------------------------
49 - **Alternative A:** Utilizes RJ45 conductors 1, 2, 3 and 6. In either case of
52 (Medium Dependent Interface) or MDI-X (Medium Dependent Interface Crossover)
55 - **Alternative B:** Utilizes RJ45 conductors 4, 5, 7 and 8. In case of
62 Table 145-3 PSE Pinout Alternatives
63 -----------------------------------
68 +------------+-------------------+-----------------+-----------------+-----------------+
70 | | (MDI-X) | (MDI) | (X) | (S) |
72 | 1 | Negative V | Positive V | - | - |
73 +------------+-------------------+-----------------+-----------------+-----------------+
74 | 2 | Negative V | Positive V | - | - |
75 +------------+-------------------+-----------------+-----------------+-----------------+
76 | 3 | Positive V | Negative V | - | - |
77 +------------+-------------------+-----------------+-----------------+-----------------+
78 | 4 | - | - | Negative V | Positive V |
79 +------------+-------------------+-----------------+-----------------+-----------------+
80 | 5 | - | - | Negative V | Positive V |
81 +------------+-------------------+-----------------+-----------------+-----------------+
82 | 6 | Positive V | Negative V | - | - |
83 +------------+-------------------+-----------------+-----------------+-----------------+
84 | 7 | - | - | Positive V | Negative V |
85 +------------+-------------------+-----------------+-----------------+-----------------+
86 | 8 | - | - | Positive V | Negative V |
87 +------------+-------------------+-----------------+-----------------+-----------------+
90 - "Positive V" and "Negative V" indicate the voltage polarity for each pin.
91 - "-" indicates that the pin is not used for power delivery in that
94 PSE PI compatibilities
95 ----------------------
98 and the 1000/2.5G/5G/10GBaseT in the PSE 2 pairs connection.
100 +---------+---------------+---------------------+-----------------------+
105 +---------+---------------+---------------------+-----------------------+
107 +---------+---------------+---------------------+-----------------------+
109 +---------+---------------+---------------------+-----------------------+
112 - "Direct" indicate a variant where the power is injected directly to pairs
114 - "Phantom" indicate power path over coils/magnetics as it is done for
117 In case of PSE 4 pairs, a PSE supporting only 10/100BaseT (which mean Direct
121 PSE Power Interface (PSE PI) Connection Diagram
122 -----------------------------------------------
125 port, the Ethernet PHY (Physical Layer), and the PSE PI (Power Sourcing
127 simultaneously through an Ethernet cable. The RJ45 port serves as the physical
129 the Ethernet PHY for data transmission and the PSE PI for power delivery.
131 .. code-block::
133 +--------------------------+
137 +--+--+--+--+--+--+--+--+--+ +-------------+
139 | | | | | | | o-------------------+ |
140 | | | | | | o--|-------------------+ +<--- PSE 1
141 | | | | | o--|--|-------------------+ |
142 | | | | o--|--|--|-------------------+ |
143 | | | o--|--|--|--|-------------------+ PSE PI |
144 | | o--|--|--|--|--|-------------------+ |
145 | o--|--|--|--|--|--|-------------------+ +<--- PSE 2 (optional)
146 o--|--|--|--|--|--|--|-------------------+ |
148 +--+--+--+--+--+--+--+--+--+ +-------------+
150 | Ethernet PHY |
152 +--------------------------+
154 Simple PSE PI Configuration for Alternative A
155 ---------------------------------------------
157 The diagram below illustrates a straightforward PSE PI (Power Sourcing
159 setup for Power over Ethernet (PoE). This implementation is tailored to provide
160 power delivery through the data-carrying pairs of an Ethernet cable, suitable
161 for either MDI or MDI-X configurations, albeit supporting one variation at a
164 .. code-block::
166 +-------------+
167 | PSE PI |
168 8 -----+ +-------------+
169 7 -----+ Rail 1 |
170 6 -----+------+----------------------+
171 5 -----+ | |
172 4 -----+ | Rail 2 | PSE 1
173 3 -----+------/ +------------+
174 2 -----+--+-------------/ |
175 1 -----+--/ +-------------+
177 +-------------+
181 - Pins 1 and 2, as well as pins 3 and 6, are utilized for power delivery in
183 10/100BaseT Ethernet networks where these pairs are used for data.
184 - Rail 1 and Rail 2 represent the positive and negative voltage rails, with
186 More advanced PSE PI configurations may include integrated or external
188 compatibility with both MDI and MDI-X configurations.
190 More complex PSE PI configurations may include additional components, to support
192 additional power delivery capabilities such as 2-pair or 4-pair power delivery.
194 .. code-block::
196 +-------------+
197 | PSE PI |
198 | +---+
199 8 -----+--------+ | +-------------+
200 7 -----+--------+ | Rail 1 |
201 6 -----+--------+ +-----------------+
202 5 -----+--------+ | |
203 4 -----+--------+ | Rail 2 | PSE 1
204 3 -----+--------+ +----------------+
205 2 -----+--------+ | |
206 1 -----+--------+ | +-------------+
207 | +---+
208 +-------------+
210 Device Tree Configuration: Describing PSE PI Configurations
211 -----------------------------------------------------------
213 The necessity for a separate PSE PI node in the device tree is influenced by
214 the intricacy of the Power over Ethernet (PoE) system's setup. Here are
215 descriptions of both simple and complex PSE PI configurations to illustrate
216 this decision-making process:
218 **Simple PSE PI Configuration:**
219 In a straightforward scenario, the PSE PI setup involves a direct, one-to-one
220 connection between a single PSE controller and an Ethernet port. This setup
223 configurations, detailing the PSE PI within the existing PSE controller's node
226 association of power delivery to a specific Ethernet port.
228 **Complex PSE PI Configuration:**
229 Contrastingly, a complex PSE PI setup may encompass multiple PSE controllers or
230 auxiliary circuits that collectively manage power delivery to one Ethernet
234 these instances, a dedicated PSE PI node becomes essential for accurately
236 interactions between different PSE controllers, the support for various PoE
242 For simple PSE setups, including PSE PI information in the PSE controller node
245 benefit from a dedicated PSE PI node. This method adheres to IEEE 802.3
249 PSE PI Node: Essential Information
250 ----------------------------------
252 The PSE PI (Power Sourcing Equipment Power Interface) node in a device tree can
254 delivery capabilities and configurations of a PoE (Power over Ethernet) system.
256 necessity and reasons why they might not be found within a PSE controller node:
260 - *Description:* Identifies the pairs used for power delivery in the
261 Ethernet cable.
262 - *Necessity:* Essential to ensure the correct pairs are powered according
264 - *PSE Controller Node:* Typically lacks details on physical pair usage,
269 - *Description:* Specifies the polarity (positive or negative) for each
271 - *Necessity:* Critical for safe and effective power transmission to PDs.
272 - *PSE Controller Node:* Polarity management may exceed the standard
273 functionalities of PSE controllers.
275 3. **PSE Cells Association**
277 - *Description:* Details the association of PSE cells with Ethernet ports or
278 pairs in multi-cell configurations.
279 - *Necessity:* Allows for optimized power resource allocation in complex
281 - *PSE Controller Node:* Controllers may not manage cell associations
286 - *Description:* Lists the PoE standards and configurations supported by the
288 - *Necessity:* Ensures system compatibility with various PDs and adherence
290 - *PSE Controller Node:* Specific capabilities may depend on the overall PSE
291 PI design rather than the controller alone. Multiple PSE cells per PI
296 - *Description:* Outlines additional protection mechanisms, such as
298 - *Necessity:* Provides extra safety and stability, complementing PSE
300 - *PSE Controller Node:* Some protections may be implemented via
301 board-specific hardware or algorithms external to the controller.