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AR# 24554

LogiCORE Tri-Mode Ethernet MAC v3.1/v3.2 and Gigabit Ethernet MAC v8.0/v8.1 - Multicast pause frames not recognized by MAC when Flow Control is enabled


In the Tri-Mode Ethernet MAC v3.1 and v3.2 and in the Gigabit Ethernet MAC v8.0 and v8.1, when Flow Control is enabled and a Multicast PAUSE frame is received, the Transmit side of the MAC does not pause and the frame is passed on to the client marked as a good frame. In the statistics vector, bit 4 (multicast) and bit 19 (control frame) are set, but bit 23 (pause frame) is not set.

If the MAC was operating correctly, the reception of the Multicast PAUSE frame should pause the transmit side of the MAC and be passed on to the client marked as a bad frame.


To work around this issue, the Multicast address (01-80-C2-00-00-01) can be set as the PAUSE address in the configuration_vector or via the host interface. This problem did not occur in v7.0 of the GEMAC core, v2.2 of the TEMAC core, or earlier cores. This problem will be fixed in v8.2 of the GEMAC core and v3.3 of the TEMAC core, scheduled for release in the 9.1i IP Update 1 in March 2007.

AR# 24554
Date Created 09/04/2007
Last Updated 12/15/2012
Status Active
Type General Article