Comment to T10/05-145r0 SAS-1.1: BreakWait issue resolution

Gil Romo gil.romo at
Fri Apr 22 10:15:18 PDT 2005

* From the T10 Reflector (t10 at, posted by:
* Gil Romo <gil.romo at>
Accidentally, perhaps, this proposal demonstrates that a BREAK primitive can 
abort a connection request before the request is received by the destination.

In Figures 6 and 7, low-priority OPEN address frame 1 establishes a pathway 
completely through expander 1 and expander 2.  Later, high-priority OPEN address 
frame 2 is received by expander 2 and is transmitted from expander 2 after 
causing a backoff reverse response.

BREAK 1 breaks the pathways through both expanders 1 and 2, even before OPEN 
address frame 2 is received by expander 1.  BREAK 1 is also received as a 
response to OPEN address frame 2.  Clearly, the generation of BREAK 1 is not 
intended to terminate the connection request associated with OPEN address frame 

Logically speaking, high-priority OPEN address frame 2 has taken over expander 2 
resources, and reception of BREAK 1 should not break expander 2 resources.  The 
current behavior results in a useless connection request.

Gilbert Romo
Voice: (949) 389-6266                QLogic Corporation
E-mail: gil.romo at          Aliso Viejo, California

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