IEEE Std 1711.2-2019 pdf download – IEEE Standard for Secure SCADA Communications Protocol (SSCP).
The VERSION field holds the version of SSCP in use. An SSCP frame received with an unsupported version shall be dropped. Communicating devices shall use the same version. Currently the only version is 2. NOTE- The version number associated with this standard will begin at 2 so as to not be confused with pre- standard implementations of the SSCP, which may contain a value of 1 for the version number. The previous implementations are not compatible with IEEE Std 1711.2TM due to changes in the session negotiation process. The DESTINATION, SoURCE, and LENGTH fields are all stored with the most significant octet first (ie, closest to the SYNC TOKEN field).The DESTINATION field contains the 2-octet SSCP address of the device that will receive the frame. Valid address values are 0 to 65 535, inclusive. SSCP does not support broadcast frames. If broadcast communication is necessary, the frame shall be sent to each SSCP device with which this device is configured to communicate. The SOURCE field contains the 2-octet SSCP address of the device sending the frame. Valid address values are0 to 65 535, inclusive. Each SSCP device shall be configured with its own unique SSCP address as well as the unique SSCP addresses of the remote device with which it communicates. Address settings shall be configured correctly between communication devices otherwise the communication will not work. The 1-octet PAYLOAD TYPE field specifies the type of frame and indicates the type of payload to expect. The ranges from 192 to 255 are for vendor-defined pay load ty pes. Implementers may use pay load type values in this range to include custom functionality to meet the needs of specific application domains. Implementers . shall not use vendor-defined data types as a replacement for existing data types defined in this standard. For interoperability, payload types defined in this range shall not be nccessary to operate the protocol. The remainder of the undefined pay load type range is reserved. Table 1 lists the valid payload types.