diff between Privileges and Access Level in MS CRM Dynamics 2011


In the Security in the MSCRM , there are different security implement in MSCRM, could anyboday define,what is diff between Privileges and acces level in MSCRM Dynamics 2011 ?

A Privilege is a permission to perform an action on a specific entity type in Microsoft Dynamics CRM. Privilege is MS CRM 2011 we are providing the privilege Read, Write, Delete, Assign, Share, Append and append to.

Access level is provides accessibility in particular Entity in Microsoft CRM includes four distinct access levels presented in order in MS CRM User Level, Organization level and Business Unit etc.