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AR# 32382

11.1 EDK, xps_ll_temac_v2_00_a - TEMAC Extended Multicast filtering occasionally accepts packet that should be dropped


Keywords: temac, extended, multicast, packet

TEMAC Extended Multicast filtering occasionally accepts packet that should be dropped.

This problem can only occur when extended multicast address filtering mode is included in the build (C_TEMACx_MCAST_EXTEND = 1) and it is enabled [EMultiFltrEnbl bit (bit 19) = ?1? and NewFncEnbl bit (bit 20) = ?1? in the Reset and Address Filter Register].

Occasionally, when an IP multicast frame is received and its destination address indicates that it should be dropped based on the corresponding value in the extended multicast address table, the frame is received anyway and is passed over to the receive LocalLink. The software then performs a full comparison of the destination address and drops it at that point because of the destination address match failure. The result is that more frames that could be filtered and dropped in hardware are passed to the software where they are filtered and dropped.


The patch included with this Answer Record fixes this problem for xps_ll_temac_v2_00_a in the EDK 11.1 release.

1. Download the tactical patch from:

2. Extract the archive to a temporary folder.
3. Copy the xps_ll_temac_v2_00_a directory from $XILINX_EDK\hw\XilinxProcessorIPLib\pcores\ to the <Project>\pcores folder.
4. Replace the file, <Project>\pcores\xps_ll_temac_v2_00_a\hdl\vhdl\rx_cl_if.vhd, with the file in this archive.
5. Clean the generated files and re-implement the design.

This issue should be fixed in EDK 11.2, which is scheduled to be released in mid-2009.

AR# 32382
Date 04/28/2009
Status Active
Type General Article