INRIX IQ logo

OTHER

AnnexA

The TPEG standard contains two ways to communicate TPEG data to vehicles, called Annex A and Annex B. Annex A uses the following data flow:

  1. Authentication is established between the vehicle and the back-end server, and the vehicle is identified with a drive ID.
  2. The vehicle requests TPEG data from the customer back-end server.
  3. The back-end server requests TPEG data from TPEG Connect Server, supplying a drive ID.
  4. The TPEG Connect Server returns TPEG data to the back-end server, supplying only data that has changed since the last request using the same drive ID.
  5. The back-end server returns the data to the vehicle.

Note that Annex B provides faster data flow, since once authentication is established, data does not need to flow through the back-end. It also lowers the chance of failure, since the back-end is no longer a potential failure-point when sending traffic data. And it also provides improved accuracy: by keeping track of the transaction IDs, if messages are dropped, then the TPEG server can force a refresh of all the data.