This OPC UA Interface is used to represent the traffic specification of a TSN stream. The IIeeeBaseTsnTrafficSpecificationType is formally defined in Table 10.

Table 10 – IIeeeBaseTsnTrafficSpecificationType definition

Attribute	Value
BrowseName	IIeeeBaseTsnTrafficSpecificationType
IsAbstract	True
References	NodeClass	BrowseName	DataType	TypeDefinition	Modelling Rule
Subtype of the BaseInterfaceType defined in OPC 10000-5
HasComponent	Variable	MaxIntervalFrames	UInt16	BaseDataVariableType	Mandatory
HasComponent	Variable	MaxFrameSize	UInt32	BaseDataVariableType	Mandatory
HasComponent	Variable	Interval	UnsignedRationalNumber	BaseDataVariableType	Mandatory
Conformance Units
BNM TSN Config

The MaxFrameSize of DataType UInt16 specifies the maximum size frame that will be sent by a Talker for this Stream (see IEEE 802.1Q-2018 clause 35.2.2.8.4a).

Note: According to 802.1Q MaxFrameSize only counts the number of bytes of the Ethernet payload without the media specific framing bytes. (i.e. without 8-byte preamble, 14-byte IEEE 802.3 header, 4-byte IEEE 802.1Q priority/VID Tag, 4-byte CRC, 12-byte inter frame gap). Same rules apply for counting MaxBytesPerInterval.

The MaxIntervalFrames of DataType UInt16 Variable specifies the maximum number of frames that will be sent during an Interval. (see IEEE 802.1Q-2018, clause 35.2.2.8.4b, “MaxIntervalFrames” or IEEE 802.1Qcc-2018, clause 35.2.2.10.6, “MaxFramesPerInterval”)

Interval of DataType UnsignedRationalNumber defines the time period of the TSN Stream in nanoseconds. In that interval a specified number of frames (MaxIntervalFrames) with a maximum payload size per frame (MaxFrameSize) and a maximum total number of bytes (MaxBytesPerInterval) will be transmitted. The Interval therefore shall either represent the “class measurement interval” as used for AVB based Streams (see IEEE 802.1Q-2018 clause 35 or the “Interval” parameter used in the TrafficSpecification group in IEEE 802.1Qcc-2018 clause 46.2.3.5.1).