Digi M10 manual Message Blocking, Message Priority

Digi m10 Technical Overview

inaccessible by the satellite constellation. The stored messages are transmitted when an ORBCOMM Gateway comes into satellite-transmission range. This concept applies to both sending (SC-Originated) and receiving (SC-Terminated) from a satellite modem point of view.

More documentation can be found on the kit installation CD. To learn more, navigate to C:\Program Files\Digi\Digi m10 JumpStart Kit\documents please refer to either ORBCOMM Serial Interface Specification > Figure 4.5 SC-Originated Globalgram & Figure 4.6 SC-Terminated Globalgram or ORBCOMM Serial Interface Specification > SC-ORIGINATED GLOBALGRAM &

SC-TERMINATED GLOBAL.

3.7Message Blocking

Message Blocking is an optional feature that allows customers to restrict the addresses to which their satellite modems can send messages, and those addresses that are allowed to send to a satellite modem. The Speed Dial addresses are used as permitted addresses.

3.8Message Priority

Message priority is a feature that allows messages to be processed in order of importance. The higher the priority, the faster the message moves through the network. However, the ORBCOMM message switch (OMS) does not terminate message sessions in progress; a new urgent message will remain queued until any active lower-priority message is completed.

ORBCOMM will only implement priority restrictions during periods of very heavy usage. If the system is lightly loaded and no queues, or only very short queues, are formed, there is little user benefit gained from the priority feature.

Functionally, within the ORBCOMM gateway congestion control mechanisms use priority to stop satellite modems from sending messages not meeting a customer-designated priority threshold. The satellite broadcasts the identification number of connected gateways and their minimum message priority thresholds in the downlink control information. All listening satellite modems that have messages queued for a listed gateway must refrain from sending messages below the specified priority threshold. Only queued messages with a priority at or above the minimum priority threshold are sent. Messages below the minimum priority remain in the queue until channel utilization falls below the threshold.

The available priority levels are:

0.Non-urgent

1.Normal

2.Urgent

3.Special Delivery

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