I'm new to Ethernet interface and I have a few questions regarding my next project. My requirements are to send data over ethernet from custom FPGA board to a PC over dedicated link. The throughput requirements are roughly 800Mbits/s. I need to receive commands other this link as well, but @ much lower rates. I'm planning to use external 88E1111 RGMII module and TSE MAC on the FPGA side. From what I've researched so far, I need to implement a transport stack (either TCP or UDP). Also, from what I've read, SOPC approach with NIOS will yield ~110 Mbits/s at best. Is there any reference design on how to implement TCP/UDP in hardware? Will implementing these protocols in hardware provide me with desired throughput? thanks in advance

You are really pushing the limit of Gigabit ethernet. By the time you take into account the overhead of the MAC and TCP and IP protocols and the time you're going to spend processing, you're not going to be able to get the full 800Mb/s. I'd really be surprised if your PC could keep up with this anyway. It has all the same issues. The stack is implemented in software on the PC. Jake

Are you open to other transport methods? Most people are going PCI Express these days. Can your data be easily compressed? Jake

Actually 800Mbits/s is our upper limit. We might be able to get away with 500Mbits/s, but from the sounds of it, this might also be a challenge. What would you say is a feasible upper limit on for this type of interface? PCIe is an option we're considering, but we'd like to run this board stand alone.

To my opinion, you should be able to achieve almost Ethernet 1GBit hardware speed with a FPGA hardware network stack, reduced only by the protocol overhead. Comparable results are achieved e. g. by network switches. I also expect, that you can deliver the data stream at the FPGA side. But how about the PC side? What's the data sink? I suggest to perform some basic tests with PCs if the intended throughput is feasible.

Wouldn't the PC performance depend on NIC? Does the NIC handle network layer or is it the PC processor?

Ethernet question | Altera Community

12 Replies

Altera_Forum
Honored Contributor
16 years ago
Hello everybody,

I have the same problem with the 10GbE.
I am sure that the Nios is not enough fast to provide a throughput of 6 Gbps.
However, I'm seeking a hard IP with can provide UDP protocol but every stack seams to be soft IP.
Do you know a vendor who provide a 10GbE UDP stack ?

regards.
Altera_Forum
Honored Contributor
16 years ago
--- Quote Start ---
Thank you for the interesting insights. Can you achieve the said speeds through UDP, when you connect at the socket driver level (winsock2 on windows OS), or do you need to connect the device driver at a lower level?
--- Quote End ---

On the Cyclone III (100MHz), NIOS II and TSE we're close to 900Mb with UDP. This includes hardware calculated internet checksum done while the data is being transferred into memory from other hardware to be sent by UDP. This is with highly optimized UDP packet code and TSE driver using lwIP (for a TCP connection for lower bandwidth control). The PC can keep up with these UDP bursts but also it can and will drop packets. Surprisingly, we've found even on a LAN that UDP can be error free for extended times transferring lots of data (21MB/S). But we developed a reliable UDP protocol to be safe.

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Ethernet question

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