CMMI-SVC® (Capability Maturity Model Integration for Services, owned by Carnegie Mellon University) "provides guidance for developing or improving processes that meet the business goals of an organization". CMMI models are often used as a framework for appraising the process maturity of an organization.
CMMI-SVC and YaSM share many key principles. This is no coincidence, since both models cover the activities required to establish, deliver and manage services and draw on concepts from other service management frameworks and standards, such as ITIL® and ISO/IEC 20000.
But YaSM should not be understood to be a "CMMI-SVC process model". Instead, YaSM can be used in combination with the CMMI-SVC guidance and serve as a starting point for organizations that wish to adopt CMMI-SVC.
The CMMI-SVC model contains 24 "process areas", of which 17 are "core process areas", covering basic concepts that are fundamental to process improvement in any area of interest. The other seven process areas are specific to the management of services.
In the YaSM Wiki you can find a detailed list of these process areas and how they are related to specific YaSM processes.