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How do i detect ethernet frames of layer 2 using ethereal?

Hello everyone, I am trying to implement ethernet MAC on a fpga using vhdl. I have a transmit module which generates the ethernet frame and transmits to the PC through the ethernet cable. The ethernet frame consists of preamble, sfd, destination(MAC), source(MAC), length,data,crc. I am using ethereal to detect this frame

I definitely think that my crc is right. But i am not able to detect any frames in the ethereal. I understand that by default ethereal has been set to detect ethernet frame of layer 3 or above.

But the ethernet frame which i am sending is layer2. How do i change my options in ethereal so, that i can detect this type of frame.

Ashwin

Reply to
ashwin
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Ethereal will pick up any type of ethernet frame regardless of the layers contained therein.

Have you verified your CRC against a known good frame?

Are you using the right type of cable (crossover or straight-through)?

Alan

Reply to
amyler

As posted above, Ethereal can detect any frame if the capture and display filters are clear... but it assumes that the NIC card in your machine actually receives/accepts the packet.

If the packet must meet the minimum and maximum size requirements (try 70 bytes for example) and has a proper FCS. You may be able to configure your Ethernet board to accept error packets, which might help troubleshoot the problem.

You didn't say which OS you were using, if you were capturing in "promiscuous" mode (may require admin rights), and if you have a direct (cross-over) connection or are going through a switch or hub.

Have you verified that you can receive the 'same' frame if it is sent via a different source (not your FPGA)?

Reply to
bh

bh top posted: [snip]

Ethereal uses WinPcap, which allows you to send test packets e.g.

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Have you tried setting the destination MAC address field to the broadcast address?

Reply to
Andrew Holme

Definitely use a crossover for this kind of work, direct to your computer, and no DHCP on either side - that way, there's only one place your packet can go, so you on't have to worry about your switch/router doing any funny stuff with it.

Reply to
jai.dhar

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