- 76 - TR 61850-90-5@IEC:2012(E) The least significant octet shall contain the HMAC algorithm information regarding the signature generation. The value shall be one of the values from Table 9. 11.3.2.2.4KeyID The value of Key ID is a four (4) octet value that was assigned by the KDC as a reference to the key that is in use. The Key ID selection shall be based upon the contents of the User Data: For User Data that contains payloads containing a single DataSet of information, the For User Data that contains payloads containing multiple DataSets, the Key ID shall be one of the Key IDs of the DataSets contained.Once the DataSet selection is made locally,the selected DataSet shall not be changed. For MNGT payloads, the Key ID shall be the value assigned to the DataSet provided by the KDC. 11.3.2.3 User data The session user data consists of two fields: Length and Payload. 11.3.2.3.1 Length The maximum size of theLength is based upon the maximum packet size for SPDU Length The maximum value maybe no greater than the SPDU Length-14-Signature Size. The Length attribute shall be a four (4) octet field that is an Unsigned Integer value One-hundred octets shall bereserved for the Signature part of User Data. Therefore,theallowedmaximumvalue,forthisversion,is65399octets. The value shall be the length of all of the octets in the payload. It shall not include the Signature. 11.3.3Payload The payload section, as shown in Figure 25, allows multiple user data PDUs to be aggregated within one SPDU. The types of PDUs that can be aggregated are constrained by the Session Identifier (SI) of the SPDU (see page 73). 11.3.3.1 Commonpayloadattributes The payloads of GOOsE, SV, or Tunnelled have two (2) common attributes: Simulation and APPiD. The common values are part of a sequence that begins with a tag that specifies the type of payload. The values for the different payload_type_tag(s) are: GOOSE-shall be indicated bya tag valueof 81hexadecimal. SV-shall be indicated byatagvalueof 82hexadecimal. Tunnel -shall be indicatedby a tag value of 83 hexadecimal. MNGT-shall be indicated byatag value of 84hexadecimal. - 77 - TR61850-90-5@IEC:2012(E) The production for the payload_type is: payload_type::=SEQUENCE ( payload_type_tag, simulation, APPID, ...] Thefollowingsubclausesdefinethesecommonvalues. 11.3.3.2 Simulation Simulation shall be a BOOLEAN value (e.g. one octet) and shall be as defined in IEC 61850-8-1. 11.3.3.3 APPID TheAPPID shall be a two (2)octet value andshall be as defined in IEC 61850-8-1. 11.3.3.4 GooSEpayload The GOOSE payload type is defined as: GOOSE_payload_type::=SEQUENCE { payload_type_tag, -- shall be a value of 81 hexadecimal simulation, APPID, APDU Length, GOOSE APDU The APDU Length is a two octet value, unsigned integer value, and contains the value of the number of octets of the GOOSE APDU. A GOOSEAPDU is defined as the goosePdu as defined in IEC 61850-8-1. The normative ASN.1productions can be found inIEC61850-8-1 and the following are provided for information only. IEC 61850-8-1 Specific Protocol::= CHOICE { gseMngtPdu [APPLICATION O] IMPLICIT GSEMngtPdu, goosePdu [APPLICATION 1j IMPLICIT IECGoosePdu, .. IECGoosePdu:= $ SEQUENCE gocbRef [0] IMPLICIT VISIBLE-STRING, timeAllowedtoLive [1] IMPLICIT INTEGER, datSet [2] IMPLICIT VISIBLE-STRING, golD [3] IMPLICIT VISIBLE-STRING OPTIONAL, [4] IMPLICIT UtcTime, stNum [5] IMPLICIT INTEGER, sqNum [6] IMPLICIT INTEGER, test [7] IMPLICITBOOLEANDEFAULTFALSE, confRev [8] IMPLICIT INTEGER, ndsCom [6] IMPLICIT BOOLEAN DEFAULT FALSE, numDatSetEntries [10] IMPLICIT INTEGER, [11] IMPLICITSEQUENCEOFData, allData security [12] ANY OPTIONAL -- reserved for digital signature 1 TR61850-90-5@IEC:2012(E) 78 - 11.3.3.5 Sampledvaluepayload The Sampled Value payload type is defined as: Sampled_Value_payload_type:=SEQUENCE{ payload_type_tag, -- shall be a value of 82 hexadecimal simulation, APPID, APDU Length, Sampled Value APDU The APDU Length is a two octet value, unsigned integer value, and contains t