PTI Procedure Transaction Identity

Procedure Transaction Identity: An identity which is dynamically allocated by the UE for the UE requested ESM procedures. The procedure transaction identity is released when the procedure is completed.

The EPS bearer identity and the procedure transaction identity are only used in messages with protocol discriminator EPS session management.

The PTI is been used to identify the transaction particular transaction.

2018 Mar 19  20:54:15.081  [97]  0xB0E3  LTE NAS ESM Plain OTA Outgoing Message  --  PDN connectivity request Msg

trans_id = 4 (0x4)
2018 Mar 19  20:54:15.168  [74]  0xB0E2  LTE NAS ESM Plain OTA Incoming Message  --  Activate default EPS bearer context request Msg
trans_id = 4 (0x4)
2018 Mar 19  20:54:15.170  [D9]  0xB0E3  LTE NAS ESM Plain OTA Outgoing Message  --  Activate default EPS bearer context accept Msg
trans_id = 0 (0x0)
This follows the figure 6.3.2.3
By sending trans_id as 0 the procedure will be ended.