Message Prioritization by Type Message Prioritization by Time to Expire

39 ฀ The Prioritization Module must prioritize messages by type as configured by the client

10.1.1 Message Prioritization by Type

A feature of the Prioritization module is the ability to prioritize the order of message transmission to a client by transmitting messages of specific types which have been previously defined as being high priority after of all other messages. During client session negotiation, the aircraft client will define a Prioritization policy that includes a truefalse value indicating whether or not to have messages prioritized prior to transmission. The Prioritization Module has been preconfigured with a list of high priority message type. Prior to transmission, messages are batched into groups based on the order received. The batched messages are parsed and checked against the list of high priority message types. Messages with a type that is defined as being high priority are Figure 8 - Prioritization Module Example 40 rearranged so that they are the first message in the batch that will be transmitted to the client. This allows high priority messages to be transmitted ahead of the other messages.

10.1.2 Message Prioritization by Time to Expire

A feature of the Prioritization module is the ability to prioritize the order of message transmission to a client by comparing the relative time to expire value of the message to the other messages in the client’s transmission queue. During client session negotiation, the aircraft client will define a Prioritization policy that includes a truefalse value indicating to the DMS whether or not the aircraft client wishes to have messages prioritized prior to transmission. Messages being forwarded to a client with prioritization enabled are placed in a transmission queue. Once in the queue, the DMS parses incoming messages in batches and checks for metadata data describing the message type and expiration time. The messages contained in each batch are prioritized by their relative time to expire. Soon to expire messages are set as high priority and placed in the front of the queue to be transmitted ahead of low priority messages. Once all messages in a batch have been successfully transmitted to the client, the next batches of messages in the transmission queue are sent to the aircraft client. By prioritizing messages in batches, the DMS prevents low priority messages being blocked from transmission by a large number of high priority messages.

10.2 Implementation