Section: 6.2.1 Principles of PTI handling for 5GSM procedures
Content: When the UE or the network initiates a transaction related procedure (i.e. a procedure consisting of more than one message and the messages are related), it shall include a valid PTI value in the message header of the request message or of the command message. If a response message is sent as result of a received request message or a received command message, the sending entity shall include in the response message the PTI value received within the request message or within the command message (see examples in figure 6.2.1.1, figure 6.2.1.2, and figure 6.2.1.3). If a command message is sent as result of a received request message, the sending entity shall include in the command message the PTI value received with the request message (see examples in figure 6.2.1.3). If a command message is not sent as result of a received request message, the sending entity shall include in the command message the PTI value set to "no procedure transaction identity assigned" (see examples in figure 6.2.1.4). Figure 6.2.1.1: UE-requested transaction related procedure accepted by the network Figure 6.2.1.2: UE-requested transaction related procedure rejected by the network Figure 6.2.1.3: UE-requested transaction related procedure triggering a network-requested transaction related procedure Figure 6.2.1.4: network-requested transaction related procedure not triggered by a UE-requested transaction related procedure