SIP Request for DND Status Changes on Cisco 9971 IP Phone

D.

Cisco Unified Communications Manager supports Do Not Disturb that a SIP device initiates or that a Cisco Unified Communications Manager device initiates.

A DND status change gets signaled from a SIP device to Cisco Unified Communications Manager by using the SIP PUBLISH method (RFC3909)

A DND status change gets signaled from a Cisco Unified Communications Manager to a SIP device by using a dndupdate Remote-cc REFER request.

Cisco Unified Communications Manager can also publish the Do Not Disturb status for a device, along with the busy and idle status for the device.

References: http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/6_1_1/ccmfeat/cmfsgd611/fsdnd.html.

The correct answer is B. NOTIFY.

When a user activates or deactivates the Do Not Disturb (DND) feature on their Cisco Unified Communications Manager (CUCM), the CUCM sends a NOTIFY message to the registered Cisco 9971 IP Phone(s) to signal the change in DND status.

SIP (Session Initiation Protocol) is a signaling protocol used in Voice over IP (VoIP) communications to initiate and terminate voice and video calls. SIP requests are sent between endpoints to establish and manage sessions.

The OPTIONS request is used by SIP endpoints to check the availability and capabilities of other endpoints. The INFO request is used to convey information during a session. The REFER request is used to transfer a call to another endpoint. The UPDATE request is used to modify the state of an ongoing session.

The NOTIFY request, also known as a SIP event notification, is used to signal changes in the state of a SIP resource. It is sent from a SIP server or endpoint to a client to inform it of an event that has occurred, such as a change in the DND status of a phone.

Therefore, in this scenario, the correct SIP request used by CUCM to signal DND status changes to a Cisco 9971 IP Phone is NOTIFY.