[Coral-dev] SNAP header

[Steve Bernard]

Joerg,

This doesn't seem possible with CoralReef 3.5.1 and FORE 200Es. Are you 
suggesting an edit to 'crl_trace'? Or is there a method that I'm not seeing?

Thanks,

Steve


Joerg Micheel wrote:
> On Mon, Mar 03, 2003 at 10:41:24PM -0800, David Moore wrote:
> 
>>On Tue, Mar 04, 2003 at 01:05:50AM -0500, Steve Bernard wrote:
>>
>>>It seems that the SNAP header is causing me to lose several bytes of L4 
>>>data. I am currently using FORE-200E's so it's either 48-bytes or 
>>>everything. My capture and storage requirements make the 'everything' 
>>>impractical but, losing the L4 data makes the captures much less useful. 
>>>Am I missing something, or is this something that will require some 
>>>development with Perl and CRL.pm?
>>
>>If your network has an LLC/SNAP header at the front of packets
>>there is nothing you can do about that if you can only capture the
>>first cell.  The first ATM cell only has 48 bytes, which includes
>>that header.  Your other choice is to capture everything, but only
>>write out part of what you see, for example changing crl_to_pcap
>>to truncate packets at whatever length you desire.
> 
> 
> Or capture the first two ATM cells of each AAL5 frame.
> 
> 	Joerg