Low network throughput in window vista

Hi

I have a question regarding network throughput in widows. I'm running the same code in windows and ubuntu (using sockets from boost). Simplified the application just consists of one thread creating a udp packet and then send it over and over in a loop. In linux I get a throughput of ~610 Mbit/s, while in windows vista I only get ~90 Mbit/s.

Does someone have a slightest idea why this is? The same equipment is used in both cases. I have also tried using rtpplay tool to generate traffic with the same result, so I do not think it has anything to do with my code. I have also tried to disable firewalls etc in windows.

Thank you for any input or ideas.
- Daniel

This is awfully close to 100 Mb/s and 1000 Mb/s. My first guess would be that one of the connections is operating at 1000 Mb/s Full Dup, and the other is not.

Can you confirm that each adapter is setup and running at 1000 Mb/s Full Duplex?

Hi, and thank you for answering.

I was thinking more if there is anything known that might be slowing down the speed. The firewall might be one such service that might do it I guess, but that one I have already tried to disable.

As default I let the card detect the speed itself, and it does detect 1.0 Gbps network, but I have also tried to manually setup 1.0 Gbps full duplex.

What size are the packets you're sending? Different OSs can have different optimal packet sizes. I can see this possibly being the cause.

Hi

~1500 bytes. No fragmentation is done. But even if it's not optimal size I doubt that the difference should be this big?

Regards,
- Daniel

Quote:

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Originally Posted by Fragge

But even if it's not optimal size I doubt that the difference should be this big?

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Actually, it wouldn't surpise me at all. The two OSs could translate packets in entirely different ways. For example, if one OS does error checking on each packet and the other just checks the final concatenation, this could be significantly different.

Either way, that's a small packet size. I would up it to at least 1Kbit (8192 bytes).

Sure, I guess it will not hurt to try.. but then it will be larger than MTU, which it can't be for what I am doing.

btw, what error check do you talk about? Is it not only the checksum on the ip header that is checked? Concatenation?

I do understand that wireless networks can have major performance issues if you send small packets, and I don't think 1500 byte is a small udp packet..

I'm just trying to understand, no offence! :-)
Thank you anyway, I will try to increase the size and come back with the result.

Regards,
- Daniel