In 2005, Microsoft submitted WS-Management for DMTF standardization along with 12 other companies. It simply provides a standard for building XML messages using web service standards. It can be used to manage PCs, devices, Web services and other manageble entities. The messages that are provided by WS-Management are the conventions of Simple Object Access Protocol aka SOAP.
SOAP is a protocol specification relies on XML for its message format. It allows for the use of different transport protocols and uses HTTP as a transport protocol.
As for WinRM, it is the implementation of WS-Management protocol by Microsoft. It provides a firewall-friendly, HTTP based way to manage hardware and operating systems across different vendors. Moreover Windows PowerShell remote feature works on WinRM technology. You can manage not only Windows systems but also non-windows systems such as Unix computers. Windows systems are managed over WMI and non-windows systems are managed over DCOM.
All data that is captured using WinRM are formatted in XML as follow:
As of January 30, 2013, WS-Management was adopted as an international ISO/IEC standard.
That is really really important since that means using WS-Management protocol to manage complex systems will be much more simplified. All new System Center components and Windows Server 2012 aka Cloud OS are using WS-Management and Win-RM.
That is exactly means that, if you decide to manage your cloud environment with System Center and Windows Server 2012, you will also have ISO/IEC standard while managing remote systems.
In addition to this, Microsoft has designed Open Managed Infrastructure (OMI) as an open source project. It helps you to implement a standards-based management service into any device from a free open source package using WS-Management ISO/IEC standard.