SPRZ452I july 2018 – may 2023 AM6526 , AM6528 , AM6546 , AM6548
PRU-ICSSG: Erroneous FDB aging behavior during switch operation with bucket size of 8
When the PRU-ICSSG is configured as a 1Gbps Ethernet switch, and the FDB is configured with a bucket size of 8, during an FDB lookup there the "touch bit" indicating the entry lookup match may be incorrectly set.
The FDB lookup can be initiated by either port or by host action. Each row within the FDB has 4 “buckets,” or 32 Bytes, and in 8-bucket configuration there are two rows that hold the entries corresponding to the hardware lookup. The error is caused by the touch bit in the even row being updated regardless of whether the specific match is to the even or odd row. For example, entry #4 was an SA hit, but entry #0 has its touch bit set; or entry #5 was an SA hit, but entry #1 has its touch bit set.
Use bucket size of 2 or 4 to avoid. If a bucket size of 8 is desired, dynamic entries must be populated only in the even rows of the table.