Is Windows OS eligible for License Mobility through SA?

No. Neither Windows Server nor Windows Desktop (client) OS licenses are eligible for License Mobility through SA. SPLA partners can host these licenses though in their datacenter provided the underlying physical server hardware is dedicated to the specific end-customer.

This may be an excellent opportunity for our service provider partners to take advantage of the Softlayer program. Through rhipe, you are able to rent/subscribe Softlayer infrastructure (bare metal) on a monthly basis to avoid the huge burden of CAPEX spend on new servers and still cater to the ‘dedicated hosting’ requirements when running end-customer’s Microsoft Windows Server/Desktop OS volume licenses.