Network mobility and the level of session continuity that will be provided during PDU session relocation: SSC mode 1: a PDU session with SSC mode 1 will remain anchored on the same PDU ses- sion anchor throughout the lifetime of the PDU session. PDU sessions for central services would therefore typically use SSC mode 1. SSC mode 2: the goal of SSC mode 2 is to enable the network to re-anchor a PDU session, i.e. to re-establish a PDU session to a PDU session anchor that is located closer to the location of the UE. To achieve this, the network releases the PDU session and as part of this, requests the UE to establish a new PDU session to the same data network immediately. It is worth mentioning that this concept already existed in EPS where the MME can deactivate a PDN connection and request the UE to reactivate it again immediately to enable the MME to select a PGW that is located closer to the UE. SSC mode 3: this mode is like SSC mode 2 with the key difference that the PDU session to the new, more closely located PDU session anchor is established before the session to the previous PDU session anchor is released. The UE will receive a different IP address for the new PDU session. However, given that both PDU sessions remain active for some time, applications can be gracefully bound to the new IP address and, by this, get relocated from the old to the new PDU session. In summary, the benefit of SSC mode 3 (see Figure 3.2.9) is that the UE does not suffer a loss of connectivity while the user-plane path for access to local services is updated. The SSC mode for a PDU session is determined by the SMF based on subscription infor- mation and based on the SSC mode requested by the UE (if provided). It is worth mention- ing that the operator can influence the SSC mode to be requested by the UE for specific applications by providing SSC mode selection policy (SSCMSP) as part of the URSP (see Section 3.2.2.2). New local data network Central (R)AN data network Previous local data network Figure 3.2.9 SSC mode 3 - PDU Sessio