Multiple connections or I_T_x_x nexus

Chris.Malakapalli at Chris.Malakapalli at
Tue Feb 25 08:20:54 PST 2003

* From the T10 Reflector (t10 at, posted by:
* Chris.Malakapalli at
I have somewhat a related question to the wide port question posted
earlier. Under section 4.1.9 of SAS rev 3d , page 35, case b states with
reference to Fig. 20 that:

"the connections labeled A and C are an example of one target port with
connections to multiple initiator ports" ...

The question is can these connections be concurrently active to support two
separate I_T_x_x nexus? Given that there is no provision in the OPEN
address frame to specify which phy to use for the connection, my feeling is
they cannot be active at the same time, but am hoping someone could clarify
this for me.

Also, there seem to be other areas in the spec, where this subject is being
discussed. For instance, according to 7.11.1 on page 177,

"A wide port  may have separate connections on each of its phys"

Again, can these connections be active at the same? If not, is it true then
that a wide port can support only a single connection at a time and all
phys support that same connection, in which case, the above sentence could
be interpreted as misleading. In rev 3c, there was some discussion of
connection at a link layer (between the phys) and now in rev 3d, it appears
to have been removed.

Thanks for your help.

Chris Malakapalli
Seagate Technology

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