Essentially, it’s like a little message that says “”
Now let’s break down what this header actually looks like. It consists of several different fields or sections, each with its own purpose:
1. Header Length (HL) This tells us how many bytes are in the entire header section. For example, if HL is 8, that means there are 8 bytes total for this particular message.
2. Message Type (MT) This indicates what type of information is being transmitted. There are several different types of messages, including safety-related alerts, traffic flow data, and more. For example, if MT is set to “0x1”, that means we’re dealing with a safety-related alert message.
3. Source Address (SA) This identifies the vehicle sending the message. Each ITS system has its own unique address, which helps ensure that messages are delivered to the correct destination. For example, if SA is set to “0x12345678”, that means we’re dealing with a message from Vehicle ID 12345678.
4. Destination Address (DA) This identifies the vehicle receiving the message. Again, each ITS system has its own unique address to ensure proper delivery of messages. For example, if DA is set to “0xABCDEFGH”, that means we’re dealing with a message intended for Vehicle ID ABCDEFGH.
5. Sequence Number (SN) This keeps track of the order in which messages are sent and received. Each ITS system has its own sequence number, which helps ensure that all messages are delivered in the correct order. For example, if SN is set to “0x1234”, that means we’re dealing with message #1234 within this particular communication session.
6. Message Length (ML) This tells us how many bytes are in the entire message section, including any data payloads or other information being transmitted. For example, if ML is set to “0x80”, that means we’re dealing with a message that contains 128 bytes of data.
7. Data Payload (DP) This is where all the juicy details get stored! Depending on the type of message being transmitted, DP might contain things like safety-related alerts, traffic flow data, or other important information. For example, if we’re dealing with a safety-related alert message, DP might include information about an upcoming road closure or a dangerous weather condition.
It may sound complicated at first glance, but once you break it down into its component parts, it’s actually pretty straightforward. And who knows? Maybe someday soon we’ll all be driving around in cars that communicate with each other using this very same technology!