Hi All,
Got an update from Mike McNamara, he has forwarded a white paper,
SFP+ Direct Attach Copper Interoperability Demonstration White
In summary
The 10GSFP+Cu interoperability demonstration and this white paper are the result of collaboration
between a broad set of semiconductor, system, and cable vendors. Full matrix interoperability to the
limits of the specification impressively demonstrated that the specification was adequately developed.
The favorable results also give IT managers a high degree of confidence that an interoperable and
highly-available 10 Gigabit Ethernet network can be achieved when using equipment from multiple
vendors with SFP+ host ports and SFP+ cable assemblies that are compliant to SFF-8431.

Full White Paper is attached.
Regards,
Richard