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Altera_Forum
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16 years ago

Low latency 1gigabit Ethernet MAC

Hello everybody :)

Anyone can refer me to a MAC that have the minimum latency as possible ? A MAC for the 1gigabit operation (we think use Stratix 4 fpga)

Thank you

Shalom

7 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    What do you mean by 'latency'?

    I guess that the delay between the time some data is received on the MII interface and the time when it is available on the stream interface for a TSE MAC is quite small and constant. But if you add the latency due to the software part, until the data is available at the UDP or TCP level will be quite higher, and will depend on the OS, IP stack and driver used. This latency could be reduced by using some hardware acceleration/implementation of the higher level of the stack.
  • Altera_Forum's avatar
    Altera_Forum
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    Like you says. I mean the "delabetween the time some data is received on the MII interface and the time when it is available on the stream interface"

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    Altera_Forum
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    In that case I don't think that you'll see a big difference between MACs. With the TSE you can remove the FIFOs to reduce it, but you'll still have a few cycles of latency due to clock domain crossing logic.

  • Altera_Forum's avatar
    Altera_Forum
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    Ok, thank you.

    In xilinx fpga there are hard coded mac.

    Does it mean that there is less latency ?

    Shalom
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    Altera_Forum
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    I don't think so. But what is your problem exactly? Is the TSE's latency that high?