ge S1-AP EU CONTEXT RELEASE REQUEST. 10) The source eNB entity responds to the former MME entity with the message S1-AP EU CONTEXT RELEASE COMPLETE to acknowledge the received message. 11) The release of the temporary bearer at the former SGW entity is triggered by the former MME entity by sending the message GTPv2-C DELETE INDIRECT FORWARDING TUNNEL REQUEST. 12) The former SGW entity responds to the former MME entity with the message GTPv2-C DELETE INDIRECT FORWARDING TUNNEL RESPONSE to acknowledge the received message. 13) The release of the context at the former SGW entity is triggered by the former MME entity by sending the message GTP-C DELETE SESSION REQUEST. 14) The former SGW entity responds to the former MME entity with the message GTP-C DELETE SESSION RESPONSE to acknowledge the received message. VoLTE and ViLTE 15) The release of the temporary bearer at the new SGW entity is triggered by the new MME entity by sending the message GTPv2-C DELETE INDIRECT FORWARDING TUNNEL REQUEST. 16) The new SGW entity responds to the new MME entity with the message GTPv2-C DELETE INDIRECT FORWARDING TUNNEL RESPONSE to acknowledge the received message. 7.4. PS-PS inter-system handover 7.4.1. Functional architecture PS-PS inter-system handover impacts the serving GPRS support node (SGSN) of 2G/3G mobile network and possibly the radio network controller (RNC) if the feature Direct Tunnel is implemented. The SGSN entity plays for 2G/3G mobile networks the same role as the MME entity for a 4G mobile network. The RNC entity plays for a 3G mobile network the same role as the eNB entity regarding the control of the mobile connection and the allocation of resources on the radio interface. The feature Direct Tunnel, specific to a 3G mobile network, allows for direct transfer traffic between the RNC and gateway GPRS support node (GGSN) entities without passing through the SGSN entity. The GGSN entity plays for 2G/3G mobile networks the same role as the PGW entity for 4G mobile network. The SGW entity ensures the anchor point of 2