Method and apparatus for indirect data forwarding

A method performed by a serving gateway entity in a first system, comprising:

• receiving, from a mobility management node in the first system, a request for creating an indirect data forwarding tunnel, wherein the request comprises an indication flag indicating to the serving gateway entity that an indirect data forwarding tunnel is to be created with a user plane function entity in a second system;
• processing the request to generate a response for the request;
• and
• sending, to the mobility management node, the response generated for the request, wherein:
• the indication flag is present and set to 1, when the indirect data forwarding tunnel is required for at least one user plane route to or from the user plane function entity in the second system during an inter system handover via an N26 interface;
• the indication flag is absent or is present and not set to 1, when the indirect data forwarding tunnel is required for a mobility procedure other than the inter system handover via the N26 interface;
• the inter system handover is from the first system to the second system or from the second system to the first system;
• and
• the first system is an evolved packet system (EPS) and the second system is a fifth generation system (5GS).

A mobility management node in a first system, the mobility management node comprising:

• a processor;
• and
• a memory operably coupled to the processor and containing instructions executable by said processor, whereby said mobility management node is operative to:
• send, to a serving gateway entity in the first system, a request for creating an indirect data forwarding tunnel, where the request comprises an indication flag indicating to the serving gateway entity that an indirect data forwarding tunnel is to be created with a user plane function entity in a second system;
• and
• receive a response to the request from the serving gateway entity, wherein:
• the indication flag is present and set to 1, when the indirect data forwarding tunnel is required for at least one user plane route to or from the user plane function entity in the second system during an inter system handover via an N26 interface;
• the indication flag is absent or is present and not set to 1, when the indirect data forwarding tunnel is required for a mobility procedure other than the inter system handover via the N26 interface;
• the inter system handover is from the first system to the second system or from the second system to the first system;
• and
• the first system is an evolved packet system (EPS) and the second system is a fifth generation system (5GS).