D.3.1 General

23.4013GPPGeneral Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) accessRelease 18TS

The interoperation procedures describe information flows for Gn/Gp SGSNs and other EPS network elements. All messages between Gn/Gp SGSN and MME, between Gn/Gp SGSN and HSS and between Gn/Gp SGSN and P‑GW as well as the therein contained information elements are the same as specified for the adequate TS 23.060 [7] procedures that are between Gn/Gp SGSNs. These messages and procedure step descriptions are taken from TS 23.060 [7] for explanatory purposes only. These descriptions are in italic text and shall not be modified by the interoperation procedures. It cannot be assumed that the messages and procedure step descriptions that are taken from TS 23.060 [7] will be updated when modifications or corrections are performed for TS 23.060 [7]. If there are any discrepancies for these messages and procedure step descriptions TS 23.060 [7] takes precedence. The messages between the MME and any other node than the Gn/Gp SGSN as well as the therein contained information elements are the same as specified in the main body of this technical specification for the inter RAT Routing Area Update procedure. If there are any discrepancies for these messages the descriptions from the main body of this Technical Specification take precedence.

An operator that has pre-Rel‑8 SGSNs in its network should use separate EPS bearers for IPv4 and IPv6 addressing, such that both addresses can be maintained when moving to a pre-Rel‑8 SGSN from a Rel‑8 SGSN or MME (see clause 5.3.1). This is configured into the SGSN and MME nodes which set the Dual Address Bearer Flag depending on whether a UE may or may not be handed over to a pre-Rel‑8 SGSN, as specified in clauses 5.3.2.1 and 5.10.2.

An operator supporting emergency services shall not have pre-Rel-9 SGSNs in its network where a UE may be handed over.