IEEE 802.3cm:2020 pdf free download – Physical Layer and Management Parameters for 400 Gb/s over MultimodeFiber
Figure 138-1 shows the relationship of the PMDs and MDIs (shown shaded) with other sublayers to theISO/IEC Open System Interconnection (OSI) reference model. 50 Gigabit Ethernet is introduced inClause 131 and the purpose of each PHY sublayer is summarized in 131.2.100 Gigabit Ethernet isintroduced in Clause 80 and the purpose of each PHY sublayer is summarized in 80.2.200Gigabit Ethernetand 400 Gigabit Ethernet areis introduced in Clause 116 and the purpose of each PHY sublayer issummarized in 116.2.
50GBASE-SR,100GBASE-SR2，and-200GBASE-SR4,and 400GBASE-SR8 PHYs with the optionalEnergy-Efficient Ethernet (EEE) fast wake capability may enter the Low Power ldle(LPI) mode to conserveenergy during periods of low link utilization (see Clause 78).The deep sleep mode ofEEE is not supported.
Further relevant information may be found in Clause 1 (terminology and conventions, references, definitionsand abbreviations) and Annex A (bibliography，referenced as [B1]，[B2]，etc.). The 50GBASE-SR,100GBASE-SR2, and-200GBASE-SR4, and 400GBASE-SR8 sublayers provide point-to-point 50,100, and200, and 400 Gigabit Ethernet links over one, two, or four, or eight pairs of multimode fiber, up to at least100 m.
For the 200GBASE-SR4 and 400GBASE-SR8 PMDs, the bit error ratio(BER) when processed by the PMA(Clause 120) shall be less than 2.4 × 10‘ provided that the error statistics are sufficiently random that thisresults in a frame loss ratio (see 1.4.275) of less than 1.7 × 10-12for 64-octet frames with minimuminterpacket gap when additionally processed by the PCS(Clause 119).For a complete Physical Layer, theframe loss ratio may be degraded to 6.2 ×10-ll for 64-octet frames with minimum interpacket gap due toadditional errors from the electrical interfaces. If the error statistics are not sufficiently random to meet thisrequirement, then the BER shall be less than that required to give a frame loss ratio of less than 1.7×10-12for 64-octet frames with minimum interpacket gap.
An upper bound to the delay through the PMA and PMD is required for predictable operation of the MACControl PAUSE operation.
The sum of the transmit and receive delays at one end of the link contributed by the 50GBASE-SR PMDincluding 2 m of fiber in one direction shall be no more than 1024 bit times (2 pause_quanta or 20.48 ns).
The sum of the transmit and receive delays at one end of the link contributed by the 100GBASE-SR2 PMDincluding 2 m of fiber in one direction shall be no more than 2048 bit times (4 pause_quanta or 20.48 ns).
The sum of the transmit and receive delays at one end of the link contributed by the 200GBASE-SR4 PMDincluding 2 m of fiber in one direction shall be no more than 4096 bit times (8 pause_quanta or 20.48 ns).
The sum of the transmit and receive delays at one end of the link contributed by the 400GBASE-SR8 PMDincluding 2 m of fiber in one direction shall be no more than 8192 bit times (16 pause_quanta or 20.48 ns).
Descriptions of overall system delay constraints and the definitions for bit times and pause_quanta, can befound in 131.4 for 50GBASE-SR,in 80.4 for 100GBASE-SR2,and in 116.4 and its references for200GBASE-SR4 and 400GBASE-SR8.