Messages are sent to a short message service center (SMSC), which provides a "store and forward" mechanism. It attempts to send messages to the SMSC's recipients. If a recipient is not reachable, the SMSC queues the message for later retry.Gil Held: "Data over Wireless Networks." pages 105–11, 137–38. Wiley, 2001. Some SMSCs also provide a "forward and forget" option where transmission is tried only once. Both mobile terminated (MT, for messages sent to a mobile handset) and mobile originating (MO, for those sent from the mobile handset) operations are supported. Message delivery is "best effort", so there are no guarantees that a message will actually be delivered to its recipient, but delay or complete loss of a message is uncommon, typically affecting less than 5 percent of messages. Some providers allow users to request delivery reports, either via the SMS settings of most modern phones, or by prefixing each message with *0# or *N#. However, the exact meaning of confirmations varies from reaching the network, to being queued for sending, to being sent, to receiving a confirmation of receipt from the target device, and users are often not informed of the specific type of success being reported.
Messages are sent to a short message service center (SMSC), which provides a "store and forward" mechanism. It attempts to send messages to the SMSC's recipients. If a recipient is not reachable, the SMSC queues the message for later retry.Gil Held: "Data over Wireless Networks." pages 105–11, 137–38 Wiley, 2001. Some SMSCs also provide a "forward and forget" option where transmission is tried only once. Both mobile terminated (MT, for messages sent to a mobile handset) and mobile originating (MO, for those sent from the mobile handset) operations are supported. Message delivery is "best effort", so there are no guarantees that a message will actually be delivered to its recipient, but delay or complete loss of a message is uncommon, typically affecting less than 5 percent of messages. Some pro.v.iders allow users to request delivery reports, either via the SMS settings of most modern phones, or by prefixing each message with *0# or *N#. However, the exact meaning of confirmations varies from reaching the network, to being queued for sending, to being sent, to receiving a confirmation of receipt from the target device, and users are often not informed of the specific type of success being reported