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Altera_Forum
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20 years ago

maximum ethernet speed

Hello! simple question: what are your experiences about the network speed with nios2 and lwip stack? my scenario: nios2 @ 75MHz lwip stack udp packages 1500 bytes (loop sending alway...
Altera_Forum's avatar
Altera_Forum
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20 years ago

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originally posted by revolt@Sep 25 2005, 09:44 AM

400 - 600 mbit/s. thats a word. i think that is impossible via ethernet.<div align='right'><{post_snapback}> (index.php?act=findpost&pid=9947)

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The only time I&#39;ve seen that is with Gigabit Ethernet, transferring between GHz-class machines. Given that a Nios processor is usually 50-150 MHz, you&#39;d have to be transferring 4-12 bits per CPU clock cycle (!) to meet that data rate.

I&#39;ve been testing Ethernet throughput on my board (64MHz Cyclone Nios II w/ LAN91C111) and I get a TCP data rate (one way socket) of about 450kbytes/sec, and a UDP (TFTP upload) data rate of about 300kbytes/sec. I&#39;m running the eCos OS on my board (stock drivers), though, so I&#39;m not sure how much that hurts things. During transfers, the Ethernet pretty much eats the whole CPU (I can see a lowest-priority monitor task simply stopping for several seconds). I know for sure that I don&#39;t have any hardware checksum calculation. Are there any general guidelines on what to optimize to increase this speed?