This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

USB-Ethernet adapter and bulk speed from f/w to s/w

Hello, All!

The question is kind of out of Keil's scope but would appreciate if someone will giv an idea to try.

So, I am using ST10 running on phyTEC core, and the core operates CS8900A Ethernet controller, I am using 3d party TCP/IP stack (CMX) along with my own modules. On s/w side I am sitting under MS Windows XP Pro V.2002/SP2. Laptop is Dell D610 w/ built-in ethernet adapter Broadcom NetXtreme 57xx. An application on windows side uses sockets library wsock32.lib.

The f/w works just fine if I am connected to my internal laptop's ethernet adapter. No hassle. As soon as I am using Belkin USB-Ethernet adapter, namely F5D5050, I am experiencing a drop in bulk TCP speed. Be precise, drop is of factor of order x5, i.e. something is going really wrong. I have to use the 10BT Ethernet in case of phyTEC. First, I checked f/w simply by replacing my ST10 device with 3d party device (NetBurner's network-enabled CB34-EX module working at 100BT and built on Coldfire MCF5234). In this case I have the drop around factor of ~ x300 (!) - think, because of 100BT Ethernet and because of pronounced power of MCF which makes the drop more visible. In other words, when using Belkin adapter I have only 5...10 kBytes/s, which is shame.

The adapter is supposed to work both with 10/100 Ethernet and I _did_ verify this fact by using independent refence: the web browser. I have found that the IE6.0 has pretty good effective download rate of about 500 kBytes/s for a large files even if working through the Belkin USB-Ethernet adapter. As far as I know FTP is built over TCP, so the independent test should be adequate. I also checked other USB devices I have connected to my laptop, and disconnected them - no difference, the TCP stress test results remain the same. Changes in several settings on Belkin adapter side ("properties" under Windows, however not documented) did not help. So, I should not believe this is USB2.0 who is the bottle-neck.

Additional facts: ARP cache get cleaned up before each test (MAC/IP fitting is monitored before running the test). Either adaptor disconnected and disabled if another one is in use, i.e. the only single adapter is active at the given time. F/w gets its reset before the test. Firewall and other secure stuff (up to my knowledge - what can be missed, or what can affect the performance?) is off during the tests. To remember - the internal ethernet adapter works fine with my two test systems, ST10 and MCF. So, should be some feature in a way how the IE communicates with USB/Ethernet driver?? Should mention, the test f/w just sends bulk data (random) to the s/w side in payload packets w/ size 1460 bytes or less.

Any idea?

Regards,
Nikolay.

0