Bi-directional Flow Relocation For Computation Offloading With Multiple Network Functions

While relocation of bi-directional service flows in mobile services with computation offloading, round trip delay of in-flight service packets should be kept short to provide swift responses in the services. However, when a service flow passes through multiple network functions (NFs), the in-flight service packets incur additional transmission delay every time they arrive at the NFs moving the state for the flow. The additional delay depends on the timing when each NF transmits its state and the packets' direction. Then optimizing the delay extension of the packets headed for a direction does not contribute to suppressing the round trip time extension in the bi-directional service flow. We propose a scheduling method for moving the flow states that ensures that each in-flight packet waits at most once. The method executes the state migration for each NF sequentially and drains all the delayed packets before starting moving the next flow state. Numerical evaluation results show that our method effectively reduces the waiting times of the in-flight packets.