Filters used by descriptors differs from filters used by operators. There are client-level and domain-level filters for object descriptors.
Client-level filters can specify a client by ID or login name. Domain-level filters can specify a domain by name, ID, or they can specify multiple domains belonging to a specified client by client ID or login name.
If the filter node is not blank (<filter/>) the server will return descriptor for an object, specified by filtering rule parameters. In this case there will be filter-id and id nodes in the response packet.
If the filter node is blank the server will return the server-level descriptor for a specified object. In this case there will not be filter-id and id nodes in the response packet.
A single filter node cannot contain filtering parameters presented by different nodes in XML schema, but can contain multiple filtering parameters presented by the same node in XML schema.
For details on descriptors, refer to the Descriptors section of the Programming Guide.