Altera 40-Gbps Ethernet MAC and PHY MegaCore Function - Manual (Page 81)

Conditions Triggering XOFF Frame Transmission
The TX MAC transmits XOFF frames when one of the following conditions occurs:
• Client requests XOFF transmission—A client can explicitly request that XOFF frames be sent using the
pause control interface signals. When
pause_insert_tx
is asserted and
pause_insert_time
is not
zero, an XOFF frame is sent to the Ethernet network when the current frame transmission completes.
• Host (software) requests XOFF transmission—Setting the pause control register triggers a request that
an XOFF frame be sent.
Both options are available in the 40-100GbE IP core with or without adapters.
Conditions Triggering XON Frame Transmission
The TX MAC transmits XON frames when one of the following conditions occurs:
• Client requests XON transmission—A client can explicitly request that XON frames be sent using the
pause control interface signals. If
pause_insert_tx
is asserted and
pause_insert_time
is zero, an
XON frame is sent to the Ethernet network when the current frame transmission completes.
• Host (software) requests XON transmission—Setting the pause control register triggers a request that
an XON frame be sent.
Both options are available in the 40-100GbE IP core with or without adapters.
3-34 Conditions Triggering XOFF Frame Transmission
UG-01088
2014.12.15
Altera Corporation Functional Description
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