Section: 5.14.1 Architecture Principles for Configuration Transfer
Content: Configuration Transfer between two eNodeBs follows the principles used by RAN Information Management (RIM) procedures (see clause 5.15) between UTRAN, E-UTRAN and GERAN i.e. providing a generic mechanism for the exchange of arbitrary information between applications belonging to the RAN nodes. However Configuration Transfer is only used for intra- E-UTRAN information exchange whereas RIM procedures are designed for inter-RAT information exchange involving GERAN/UTRAN. Such a separate procedure allows avoiding impacts to other RAT access systems when transferred information is added or modified. The information is transferred via the MME core network node(s). In order to make the information transparent for the Core Network, the information is included in an E-UTRAN transparent container that includes source and target eNodeB addresses, which allows the Core Network nodes to route the messages. If the information is to be transferred between a source eNodeB and a target en-gNB via a target eNodeB for Dual Connectivity with E-UTRAN as Master RAN node and NR as Secondary RAN node as defined in TS 37.340[ Evolved Universal Terrestrial Radio Access (E-UTRA) and NR; Multi-connectivity; Overall Description; Stage-2 ]  [85], the source eNodeB indicates the target en-gNB and may indicate the connected target eNodeB as described in TS 36.300[ Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 ]  [5], and the target eNode B further transfers the E-UTRAN transparent container to the en-gNB transparently. The mechanism is depicted in figure 5.14 1. An example for such transferred information is the SON information, as specified in TS 36.413[ Evolved Universal Terrestrial Radio Access Network (E-UTRAN); S1 Application Protocol (S1AP) ]  [36]. Figure 5.14-1: inter E-UTRAN Configuration Transfer basic network architecture The E-UTRAN transparent containers are transferred from the source E-UTRAN node to the destination E-UTRAN node by use of Configuration Transfer messages. An eNodeB Configuration Transfer message is used from the eNodeB to the MME over S1 interface, a MME Configuration Transfer message is used from the MME to the eNodeB over S1 interface, and a Configuration Transfer Tunnel message is used to tunnel the E-UTRAN transparent container from a source MME to a target MME over the S10 interface. Each Configuration Transfer message carrying the E-UTRAN transparent container is routed and relayed independently by the core network node(s). Any relation between messages is transparent for the MME, i.e. a request/response exchange between applications, for example SON applications, is routed and relayed as two independent messages by the MME. An MME supporting the Configuration Transfer procedures provides addressing, routing and relaying functions.