Intel® Agilex™ Hard Processor System Technical Reference Manual

ID 683567
Date 2/14/2023
Public

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17.6.8.1.2. Multicast Destination Address Filter

The MAC can be programmed to pass all multicast frames. In Perfect Filtering mode, the multicast address is compared with the programmed MAC Destination Address registers (1–31). Group address filtering is also supported. In hash filtering mode, the filter performs imperfect filtering using a 256‑bit hash table. For hash filtering, it uses the upper ten bits of the CRC of the received multicast address to index the contents of the hash table. A value of 0 selects Bit 0 of the selected register and a value of 111111 binary selects Bit 63 of the Hash Table register. If the corresponding bit is set to one, then the multicast frame is said to have passed the hash filter; otherwise, the frame has failed the hash filter.