GigaBee Bandwidth and Ethernet Compatibilty

[martinius]

I checked out the resources for GigaBee and found the EDK Project. So far I understood, It acts with a lite version of a MAC. Is there also a design for / with the Xilinx TriCore Ethernet MAC?

I assume I need a license for the EDK in combination with the board then? (I know about license costs for the TEMAC core already)

Important Question for me:

Which maximum bandwidth can be achieved with the GigaBee in the given configuration?

Is it possible to reach the maximum bandwidth of nearly 1000 MBit with this tiny FPGA?

From my Ethernet knowledge, I know, that there will be some natural loss of around 20% caused by the protocol of course, which would be acceptable.

[Oleksandr Kiyenko]

Hello Martinius,
GigaBee_XPS13.2-Axi and GigaBee_XPS14.2-FlashWriter use axi_ethernet core you need, and yes - it requre license for full functionality.
As for speed, it's difficult question as it depends on project and network parameters. You can use speed test from XAPP1026 on GigaBee_XPS13.2-Axi project.
The weakest part is Microblaze if precess Ethernet frames in hardware speed can be faster.
Almost 100% speed can be reached only with hardware implementation of Ethernet frames processing (and also many other network releted staff should be taken to account).

Best Regards,
Oleksandr Kiyenko

[martinius]

Hello, thanks so far.

since I do not have the GigaBee yet- is there an example data rate, you can give me for this demo design?

Let's say, if there was 50% sending and 50% receiving of data (interchange between two devices) -
would 200MBit be possible in both directions? (This is what I calculated).

Would you say it is possible to get along without a license? Assuming to take the opencores IP core and no EDK?

[Oleksandr Kiyenko]

Hello Martinius,
We did some test only for 100Mbit connection and got bandwidth around 95%.
As I wrote earlier this test depend on so many factors. If you want high speed you
defenetely need some core which send/receive Ethernet packets without Microblaze.
I did not work with opencores ethernet core so can't answer your question, but think
that it's possible.

Best Regards,
Oleksandr Kiyenko

[Ales Gorkic]

Hello Martinius,

I have tested extensively the performance of the GigaBee module in Gigabit mode in a camera.
We achieved up to 118MB/s sustainable TX performance which is maximal that you can achieve on Ethernet (wire speed).
The protocol was GigE Vision (UDP). We also tested with Xilinx EDK design similar to FlashWriter project and achieved the same performance.
The problem usually occurs on the PC side. At this speed you loose packets if you do not have an NDIS offload driver.

Best regards,

Ales

[martinius]

Hello both, thanks for the answer. The 95% ratio in 100MBit sounds serious to me, but I cannot believe, that in 1000MBit, one cannot achieve much more.

[Ales Gorkic]

Hi Martin,

In the Gigabit mode you have theoretical bandwidth of 125MB/s.
There is not much overhead, even in 1500bytes packets.
Using DMA engines in the FPGA side makes 99% of bandwith feasible.

Best regards,

Ales

[martinius]

Oh! I just recognized, I misunderstood the "118MB" totally. I read 118MBits instead of bytes.

So 118 MBytes is indeed very close to the maximum, and sounds very good.

I will have to figure out now in how far my application can be done with simply an FPGa and without MicroBlaze, because it seems to become more complex than expected.

[JS]

Are you working now with the GigBee?