Intel IXF1104 5.1.6.1Rx Statistics, 5.1.6.2TX Statistics, 5.1.6.3Loss-lessFlow Control, Datasheet

IXF1104 Quad-Port 10/100/1000 Mbps Ethernet Media Access Controller

The register should be programmed to 0x2667 for the 9.6 KB length jumbo frame, optimized for the IXF1104. The RMON counters are also implemented for jumbo frame support as follows:

5.1.6.1Rx Statistics

•RxOctetsTotalOK (Addr: Port_Index + 0x20)

•RxPkts1519toMaxOctets (Addr: Port_Index + 0x2B)

•RxFCSErrors (Addr: Port_Index + 0x2C)

•RxDatatError (Addr: Port_Index = 0x02E)

•RxAlignErrors (Addr: Port_Index + 0x2F)

•RxLongErrors (Addr: Port_Index + 0x30)

•RxJabberErrors (Addr: Port_Index + 0x31)

•RxVeryLongErrors (Addr: Port_Index + 0x34)

5.1.6.2TX Statistics

•OctetsTransmittedOK (Addr: Port_Index + 0x40)

•TxPkts1519toMaxOctets (Addr: Port_Index + 0x4B)

•TxExcessiveLengthDrop (Addr: Port_Index + 0x53)

•TxCRCError (Addr: Port_Index + 0x56)

The IXF1104 checks the CRC for all legal-length jumbo frames (frames between 1519 and the Max Frame Size). On transmission, the MAC can be programmed to append the CRC to the frame or check the CRC and increment the appropriate counter. On reception, the MAC transmits these frames across the SPI3 interface (jumbo frames above the setting in the “RX FIFO Transfer Threshold Port 0 ($0x5B8)” with a bad CRC cannot be dropped and are sent across the SPI3 interface). If the receive frame has a bad CRC, the appropriate counter is incremented and the RxERR flag is asserted on the SPI3 receive interface.

Jumbo frames also impact flow control. The maximum frame size needs to be taken into account when determining the FIFO watermarks. The current transmission must be completed before a Pause frame is transmitted (needed when the receiver FIFO High watermark is exceeded). If the current transmission is a jumbo frame, the delay may be significant and increase data loss due to insufficient available FIFO space.

5.1.6.3Loss-less Flow Control

The IXF1104 supports loss-less flow control when the size of a Jumbo packet is restricted to

9.6 k bytes. If this condition is met, the IXF1104 has sufficient memory resources allocated to each MAC port to ensure that, if both the IXF1104 and link partner are required to send Pause packets simultaneously during jumbo packet transfers across a medium of five kilometers of fiber, no packet data should be lost due to FIFO overflows.

78 Datasheet

Document Number: 278757

Revision Number: 007

Revision Date: March 25, 2004