RE: [ethmac] what if DATA field is of size zero

["Kevin Kay" <Kevin.Kay@espipd.com>]

Quite possibly the easiest way to get some packets would be to sniff some off a network local to you.  You may have to find a dump file player to play back what you've captured.

There are some public domain sniffers available that are quite good.  My personal favorite is Ethereal (see www.ethereal.com).  Ethereal can also capture packets originating from your design and tell you if your appended FCS is correct.  Ethereal requires WinPcap if you are running on a Windows machine.

Yet another option would be to write a simple Java app which spews out meaningless UDP packets (easily handled .  This would require the Java SDK (available for free from Sun).

Just some ideas.

Regards,
Kevin

-----Original Message-----
From: Mike Pratt [mailto:mpratt@anr.mcnc.org]
Sent: Friday, January 17, 2003 10:35 AM
To: ethmac@opencores.org
Subject: Re: [ethmac] what if DATA field is of size zero


Hi all,

I am working on a GigE MAC ... using applicable parts of the opencores 
10/100 MAC as a guide.  Does anyone have some sample Ethernet packets 
that would be suitable for testing this core?  I am particularly 
interested in checking that I have implemented crc correctly ... so they 
must have valid crc fields!  Thanks in advance for any assistance.  Regards,

Mike

Igor Mohor(opencores) wrote:

>Opencores Ethernet MAC needs a minimum size of 5 bytes for proper
>functioning. By the standard it is between 64 and 1518.
>
>Regards,
>	Igor
>
>
>
>  
>
>>-----Original Message-----
>>From: owner-ethmac@opencores.org [mailto:owner-ethmac@opencores.org]
>>    
>>
>On
>  
>
>>Behalf Of Kevin Kay
>>Sent: Thursday, January 16, 2003 2:32 PM
>>To: ethmac@opencores.org
>>Subject: RE: [ethmac] what if DATA field is of size zero
>>
>>A minimum legal packet length is 64 bytes.  If you control your entire
>>network, then I guess you can run just about any length packet you
>>    
>>
>wish (0
>  
>
>>length data field all the way to a jumbo packets of 64kbytes or so).
>>However, if it's going to be on an open network, then the acceptable
>>packet lengths are between 64 and 1518 bytes.
>>
>>Regards,
>>Kevin
>>
>>-----Original Message-----
>>From: Mohan Krishna [mailto:mkrishna@tataelxsi.co.in]
>>Sent: Thursday, January 16, 2003 7:35 AM
>>To: ethmac@opencores.org
>>Subject: [ethmac] what if DATA field is of size zero
>>
>>
>>Hi all,
>>
>>Can any one clarify me wether it is possible for the data field be of
>>size zero.
>>if so then if there is an option to disable padding in the transmitter
>>then what is the expected behavior of the receiver.
>>
>>Thanks in advance
>>
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>  
>

-- 
Mike Pratt
Network Hardware Engineer
Advanced Networking Research, MCNC
mpratt@anr.mcnc.org
ph: (919) 248-4173




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