The MWI (Message Waiting Indication) feature permits the reception of a subscriber's MWI status from a voice mail system via SIP. In a multiple-platform environment (for example, when a is present), Lotus Sametime Unified Telephony sends and receives MWI over SIP-Q.
Depending on the type of SIP endpoint the subscriber uses, the following indications are possible:
Audible message waiting indication, which provides a special dial tone (sometimes called message-waiting dial tone)
VMWI (Visual MWI), which illuminates a light (indicator) on the telephone
When a call cannot be answered by a subscriber of a voice mail system (sometimes known as a message storage and retrieval [MSR] system), the following takes place:
If the voice mail system is connected to Lotus Sametime Unified Telephony via SIP: Whenever a call is automatically redirected by a station call forwarding feature from the subscriber's DN to the voice mail system, the caller is automatically redirected to the called party's voice mailbox.
If the voice mail system is connected to Lotus Sametime Unified Telephony via SIP-Q (the voice mail system is located SIP-Q network): The caller is automatically redirected to the called party's voice mailbox. After the call is redirected, the calling party can then leave a message for the voice mail system subscriber. After the voice mail system sends a request, Lotus Sametime Unified Telephony updates the status of the MWI in order to provide the subscriber notification of the waiting message.
Lotus Sametime Unified Telephony supports the message waiting indicator notification function according to the mandatory requirements of GR-866-CORE. VMWI is supported according to GR-1401-CORE.
The indications are provided through signaling and interworking with Lotus Sametime Unified Telephony or third-party voice mail systems.
Lotus Sametime Unified Voice ensures that subscribers continue to receive accurate MWI in any of the following circumstances:
The SIP endpoint loses power temporarily.Parent topic: Call Forwarding - Voice Mail
A restart of the SIP endpoint becomes necessary.
A temporary WAN outage prevents an update of the MWI when a message was left for the subscriber.
A hot desking subscriber logs in at a remote office telephone.
The SIP endpoint is not registered at the time the SIP message would otherwise be sent.