IEEE 802.3cv-2021 pdf free download – IEEE Standard for Ethernet Amendment 12: Maintenance #15: Power over Ethernet.
79. IEEE 802.3 Organizationally Specific Link Layer Discovery Protocol (LLDP) type, length, and value (TLV) information elements
79.3.2 Power Via MDI TLV
Delete the last paragraph of 79.3.2 beginning “If a Type 1 or Type 2 power entity …”, as inserted by IEEE Std 802.3bt-2018.
Insert the following text and Table 79–2a at the end of 79.3.2 as follows:
Power entities that implement Data Link Layer classification shall support the Power via MDI TLV DLL classification extension fields shown in Figure 79–3 after the PI has been powered. Type 3 or Type 4 power entities that implement Data Link Layer classification and are connected to another Type 3 or Type 4 power entity shall support the Type 3 and Type 4 extension fields shown in Figure 79–3 after the PI has been powered. Such entities, when connected to a Type 1 or Type 2 power entity, may support the Type 3 and Type 4 extension fields shown in Figure 79–3 after the PI has been powered. Type 1 and Type 2 devices shall not include the Type 3 and Type 4 extension fields in the transmitted Power via MDI TLV.
NOTE—Some implementations of the Power via MDI TLV in Type 1 and Type 2 power entities ignore TLVs that are longer than 12 octets. In order to be interoperable with these implementations, Type 3 and Type 4 power entities are permitted to transmit 12-octet TLVs (without the Type 3 and Type 4 extension) after first transmitting at least one valid 29-octet TLV (including the Type 3 and Type 4 extension). Table 79–2a lists the recommended Power via MDI TLV formats for each combination of power entity Types.
Type 3 and Type 4 PD power entities can determine the PSE Type based on the duration of the first classification event (see 145.3.7) or based on the length of a received Power via MDI TLV (see Figure 79–3). Type 3 and Type 4 PSEs can determine the PD Type based on the PDs Physical Layer requested Class (see 145.2.8 and 145.3.6.1) or based on the length of a received Power via MDI TLV (see Figure 79–3).
79.3.8 Power via MDI Measurements TLV
79.3.8.1 Measurements
Change footnote a to Table 79–8a (as inserted by IEEE Std 802.3bt-2018) as follows:
a The valid range of this field extends beyond the allowed operating range of V Port_PD or V Port_PD-2P ; see 33.3.8.1 33.3.7.1 and 145.3.8.1.
145. Power over Ethernet
145.2 Power sourcing equipment (PSE)
145.2.5 PSE state diagrams
145.2.5.1 State diagram overview and timing
Change the third paragraph of 145.2.5.1 as follows:
A PSE performing detection using only Alternative B may fail to detect a valid PD detection signature.
When this occurs, the PSE shall not apply a voltage greater than V Off to the PI until after at least T dbo , as defined in Table 145–16, has passed before attempting another detection, except in the case of an open circuit as defined in 145.2.6.5.
See 145.2.6.5 for more information on Alternative B detection backoff requirements. Change the fifth paragraph of 145.2.5.1 as follows: Connection Ccheck timing requirements are specified in Table 145–10. Detection and power turn-on timing requirements are specified in Table 145–16. Classification timing requirements are specified in Table 145–14. Autoclass timing requirements are specified in Table 145–15.IEEE 802.3cv pdf download.