When you make a change in the Microsoft System Center Configuration Manager 2007 console, the site server creates a policy to communicate the change to the client. The site server sends the policy to the management point and the client polls for policy at the interval configured on the Computer Client Agent properties.
Policy Assignments and Policy Bodies
For efficiency, policies are created and accessed in two parts, policy assignments and policy bodies. Policy assignments can contain applicability rules so the clients download only the policy assignments that apply to them. If there is no applicability rule in the policy, it applies to all clients. Policy assignments contain pointers to the actual policy, which is contained in the policy body. The pointer is actually a URL to the policy body on the management point. The URL in the policy assignment does not actually contain the name of the management point, just a variable that the client replaces with the name of the assigned management point or, if at a secondary site, the proxy management point. For information about how clients locate their management point, see Configuration Manager and Service Location (Site Information and Management Points).
Full and Delta Policy
The first time a client requests policy assignments it requests full policy but thereafter it usually requests only the policy assignments it does not already have. The server uses a reference with the date and time stamp to determine which policy assignments the client has already received. Certain situations can trigger a full policy request, such as changing the site mode, assigning a client to a new site, or using the PolicySpy tool to request assignments.
Policy assignments are never cached. Every time the client asks for policy assignments the management point contacts the site database so the client always gets the most recent assignments. If the client is at a secondary site that is the child of its assigned site, it can request policy assignments from the proxy management point at the secondary site. If the client is roaming to another primary or secondary site in the hierarchy, the client requests policy from the assigned management point.
Policy bodies can be cached by the management point to help preserve bandwidth. If the policy is frequently requested by clients, it remains in cache (space permitting) and if it is not requested, it ages out. The policy body is never updated. If the body requires a change, the policy body is marked as obsolete and the policy assignment will point to a new policy body.
Policy and BITS
Most policy is downloaded using BITS. Client BITS settings can be configured on the BITS tab of the Computer Client Agent properties. If you configure throttling settings to apply to clients, it might take longer for clients to receive policy.