Section: 6.2.18 Support of redundant PDU sessions
Content: The 5GSM sublayer may support establishment of redundant PDU sessions (see subclause 5.33.2 of 3GPP TS 23.501[ System architecture for the 5G System (5GS) ]  [8]). In order to establish a set of two redundant PDU sessions, a UE can include a PDU session pair ID, an RSN, or both in a PDU SESSION ESTABLISHMENT REQUEST message for each of the two redundant PDU sessions (see subclause 6.4.1.2). The UE can set the PDU session pair ID, the RSN, or both according to URSP or UE local configuration (see 3GPP TS 24.526[ User Equipment (UE) policies for 5G System (5GS); Stage 3 ]  [19]). An SMF receiving a PDU session pair ID, an RSN, or both via a PDU SESSION ESTABLISHMENT REQUEST message operates as specified in subclause 5.33.2 of 3GPP TS 23.501[ System architecture for the 5G System (5GS) ]  [8]. In addition, an SMF can handle two PDU sessions as redundant even if the UE provides neither a PDU session pair ID nor an RSN in a PDU SESSION ESTABLISHMENT REQUEST message for each of the PDU sessions (see subclause 5.33.2 of 3GPP TS 23.501[ System architecture for the 5G System (5GS) ]  [8]).