Transports per physical phy

Bill.Martin at Bill.Martin at
Wed Apr 30 16:12:15 PDT 2008

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In figure 29 of SAS-2, there is a statement at the bottom of the figure
of "One or more SAS phys (with matching number of TTs and MTs) per SAS
This implies that there is only one STP or SMP transport layer per
physical phy.  Is that the intent of this diagram, and what is the
response if there is one STP or SMP connection on one logical phy when a
second connection request comes in on the other logical phy of this
physical phy?  This is analogous to multiple connection requests on
multiple physical phys (which might be part of a single wide port).  In
the later case the request would be rejected by the STP or SMP layer,
not at the port layer.
I am not sure if the diagram needs to be corrected or if there is some
other answer already available in the specification.
Bill Martin
Office of Technology
Industry Standards
916 772-3658
916 765-6875 (Cell)
bill.martin at

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