Your network contains a System Center 2012 Configuration Manager environment.
The Client Status node in the Configuration Manager console shows a downward trend in client
health.
You verify the logs on several clients.
You discover that the clients are healthy and are communicating normally to management points.
You need to identify the reasons why the Configuration Manager console displays a downward trend
in client health.
Which reasons should you identify? (Choose all that Apply.)

A.
In Client Status Settings Properties, the Heartbeat discovery during the following days interval is
shorter than the Heartbeat Discovery interval.

B.
The age set in the Delete Aged Discovery Data maintenance task is shorter than the Heartbeat
Discovery interval.

C.
The Delete Obsolete Client Discovery Data maintenance task is disabled.

D.
The Active Directory sites that are members of boundary groups are modified.

E.
Microsoft SQL Server replication to the management points stopped.

Explanation:
http://technet.microsoft.com/en-us/library/gg712308.aspx#BKMK_HeartbeatDisc
Planning for Discovery in Configuration Manager – About Heartbeat Discovery
Heartbeat Discovery differs from other Configuration Manager discovery methods. It is enabled by
default and runs on each computer client to create a discovery data record (DDR).
Heartbeat Discovery runs either on a schedule configured for all clients in the hierarchy, or if
manually invoked, on a specific client by running the Discovery Data Collection Cycle on the Action
tab in a client’s Configuration Manager program. When Heartbeat Discovery runs, it creates a
discovery data record (DDR) that contains the client’s current information including network
location, NetBIOS name, and operational status details. It is a small file, about 1KB, which is copied
to a management point, and then processed by a primary site. The submission of a Heartbeat
Discovery DDR can maintain an active client’s record in the database, and also force discovery of an
active client that might have been removed from the database, or that has been manually installed
and not discovered by another discovery method.
The default schedule for Heartbeat Discovery is set to every 7 days. If you change the heartbeat
discovery interval, ensure that it runs more frequently than the site maintenance task Delete Aged
Discovery Data, which deletes inactive client records from the site database. You can configure the
Delete Aged Discovery Data task only for primary sites.
http://technet.microsoft.com/en-us/library/gg712679.aspx
Planning for Boundaries and Boundary Groups in Configuration Manager
In System Center 2012 Configuration Manager, a boundary is a network location on the intranet that
can contain one or more devices that you want to manage. Boundaries can be an IP subnet, Active
Directory site name, IPv6 Prefix, or an IP address range, and the hierarchy can include any
combination of these boundary types. To use a boundary, you must add the boundary to one or
more boundary groups. Boundary groups are collections of boundaries. By using boundary groups,
clients on the intranet can find an assigned site and locate content when they have to install
software, such as applications, software updates, and operating system images.
When clients are on the Internet, or they are configured as Internet-only clients, they do not use
boundary information. These clients cannot use automatic site assignment and always download
content from any distribution point in their assigned site when the distribution point is configured to
allow client connections from the Internet.
Site Assignment
You can configure each boundary group with an assigned site for clients. Clients join the assigned
site of a boundary group that contains the client’s current network location. When a boundary is
added to multiple boundary groups that have different assigned sites, clients will non
deterministically select one of the sites. System Center 2012 Configuration Manager does not
support this overlapping boundary configuration for site assignment. If you make a change to the
site assignment configuration of a boundary group, only new site assignment actions are affected.
Clients that have previously been assigned to a site, do not re-evaluate their site assignment based
on changes to the configuration of a boundary group.

Further information:
http://technet.microsoft.com/en-us/library/bb632879.aspx
Delete Obsolete Client Discovery Data Task Overview
The Delete Obsolete Client Discovery Data task deletes obsolete client records from the
Configuration Manager 2007 site database. A record that is marked obsolete typically was
superseded by a newer record for the same client. The newer record becomes the client’s current
record, and the older record becomes obsolete. When you enable this task, you should configure the
schedule to run at an interval greater than the heartbeat discovery schedule. This allows clients to
send Discovery Data Records (DDRs) so that the obsolete bit is set correctly.
http://technet.microsoft.com/en-us/library/gg682132.aspx#BKMK_ClientHealth
Introduction to Client Deployment in Configuration Manager – Monitoring the Status of Client
Computers in Configuration Manager
Use the Client Status node in the Monitoring workspace of the Configuration Manager console to
monitor the health and activity of client computers in your hierarchy. Configuration Manager uses
the following two methods to evaluate the overall status of client computers.
Client Activity: You can configure thresholds to determine whether a client is active, for example:
Whether the client requested policy during the last seven days.
Whether Heartbeat Discovery found the client during the last seven days.
Whether the client sent hardware inventory during the last seven days.
When all these thresholds are exceeded, the client is determined to be inactive.
Client Check: A client evaluation engine is installed with the Configuration Manager client, which
periodically evaluates the health of the Configuration Manager client and its dependencies. This
engine can check or remediate some problems with the Configuration Manager client.
..
Client status uses the monitoring and reporting capabilities of Configuration Manager to provide
information in the Configuration Manager console about the health and activity of the client. You
can configure alerts to notify you when clients check results or client activity drops below a specified
percentage of clients in a collection or when remediation fails on a specified percentage of clients.