F-tile Architecture and PMA and FEC Direct PHY IP User Guide

ID 683872
Date 12/15/2021

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2.2.2. Determining Which PMA to Map to Which Fracture

  1. Determine the hard IP and PMA type you need (400G hard IP with FHT, 400G hard IP with FGT, or 200G hard IP with FGT).
  2. Determine the number of PMAs you need to implement your interface.
  3. Determine the fracture type (for example, st_x16 or st_x8 ) using the "Fracture Type Used by Mode" table.
  4. Identify possible fracture indices of the required fracture type that can map to the required number of PMAs. (The examples in the following sections explain this.)
  5. If there is only one possible fracture index that meets your requirement, you must use that fracture index.
  6. As you place each fracture, keep in mind that each placement blocks other fracture placements.
  7. If there are multiple fracture indices that meet your requirements:
    1. Place your interfaces’ fractures from top to bottom.
    2. Place your fractures in such a way as to be able to place all interfaces. Keep in mind that each placement blocks other fracture placements.
    3. Do not create crisscross connections when mapping fractures to PMAs.
      Figure 17. PMA-to-Fracture Connections Example
    4. Place your higher data rate interfaces first.
    5. When placing interfaces with the same data rate (same fracture type), start placing interfaces that use a higher number of PMAs first. For example, place 100GbE-2 before 100GbE-1.