DSC_58The DSRC-VU, when receiving the ECHO request, sends an ECHO response of 100 octets of data by reflecting the received command, according to ISO 14906, with no specific settings for RTM. Table 14.16 shows a bit level encoding example.U.K.
| Table 14.16 | |||
| ACTION, ECHO response frame example | |||
| Octet # | Attribute/Field | Bits in octet | Description |
|---|---|---|---|
| 1 | FLAG |  | Start flag |
| 2 | Private LID |  | Link address of the specific VU |
| 3 |  | ||
| 4 |  | ||
| 5 |  | ||
| 6 | MAC Control field |  | Response PDU |
| 7 | LLC Control field |  | ACn command n bit |
| 8 | LLC status field |  | Response available |
| 9 | Fragmentation header |  | No fragmentation |
| 10 | ACTION.response SEQUENCE { |  | ACTION response (ECHO) |
| OPTION indicator |  | IID not present | |
| OPTION indicator |  | Response parameter present | |
| OPTION indicator |  | Return status not present | |
| Fill BIT STRING (SIZE (1)) |  | Not used | |
| 11 | EID INTEGER (0..127,…) |  | No extension, EID = 0 (System) |
| 12 | ResponseParameter CONTAINER { |  | No extension, Container Choice = 2 |
| 13 |  | No extension. String length = 100 octets | |
| 14 |  | Echoed data | |
| … | … | ||
| 113 | }} |  | |
| 114 | FCS |  | Frame check sequence |
| 115 |  | ||
| 116 | Flag |  | End Flag |