SBP2 - Transaction label clarification

P.A Princy prin at
Thu Apr 22 04:08:06 PDT 1999

* From the T10 Reflector (t10 at, posted by:
* "P.A Princy" <prin at>

well. The transaction label, tlabel,  is assigned by transaction layer 
only. But as it is known to SBP2 , TL has to give this tLabel along with 
each transaction info to SBP2. SBP2 can use the same tLabel in retries too...

And TL can discard the info regarding the transaction, after getting a 
notification from SBP2 that no more retries r needed for that packet.


On Thu, 22 Apr 1999, Nitin Samar wrote:

> Query : Who assigns the transaction label ( 6 bit entry in the first quadlet of any primary packet) ?
> The transaction layer services description in IEEE Std-1394-1995 says that the transaction label is indicated to the application and is sent back by the application to transaction layer whithout any change during response. 
> The SBP2 document says ( in the description of fetch agent state machine) 
> " if a read response is received whose source_ID, destination_ID and tl(transaction label) fields match the destination_ID , source_ID and the tl fields, respectively of the read request...... " 
> >From this i conclude  that the SBP2 knows the transaction label of the read request and SBP2 assigns the tl.
> But the transction layer is not expecting the transaction label in the read request ( as per the 1394 std. document)
> Regards,
> Nitin

* For T10 Reflector information, send a message with
* 'info t10' (no quotes) in the message body to majordomo at

More information about the T10 mailing list