Should SIP require detection of duplicate tags?

Jeff Williams jlw at
Sat Apr 16 11:40:14 PDT 1994

> How bit is enormous?  SIP can have 15 initiators and up to 256 tags per 
> initiator, for a total of 65,280 possible tags.  Is this enormous enough?

I think your math is in error.  15 * 256 = 3840.   :-)

I agree with your analysis of the issue.  I did much of the work on
the queuing firmware for HP.  We only found that the overlapped tags
occurred during the debug of driver code.  I have been one who has
fought against checking of the tags once serial interfaces were 

In regards to the SIP implementations, I think that the tag checking
can be optional here also.  The checking really doesn't add to an
implementation.  If a target disconnects from an initiator, then I
think there is time in f/w to do the checking.  If the target is 
automated in the data transfers and will send the data without a 
disconnect, then the tag checking is totally useless since the
nexus information cannot be confused.  

I guess what I am saying is that I would not expect h/w to do tag 
checking.  I'm guessing that's the "right" answer, Steve.


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