A flow handover protocol to support state migration in softwarized networks

Abstract

Summary Softwarized networks are the key enabler for elastic, on‐demand service deployments of virtualized network functions. They allow to dynamically steer traffic through the network when new network functions are instantiated, or old ones are terminated. These scenarios become in particular challenging when stateful functions are involved, necessitating state management solutions to migrate state between the functions. The problem with existing solutions is that they typically embrace state migration and flow rerouting jointly, imposing a huge set of requirements on the on‐boarded virtualized network functions (VNFs), eg, solution‐specific state management interfaces. To change this, we introduce the seamless handover protocol (SHarP). An easy‐to‐use, loss‐less, and order‐preserving flow rerouting mechanism that is not fixed to a single state management approach. Using SHarP, VNF vendors are empowered to implement or use the state management solution of their choice. SHarP supports these solutions with additional information when flows are migrated. In this paper, we present SHarP's design, its open source prototype implementation, and show how SHarP significantly reduces the buffer usage at a central (SDN) controller, which is a typical bottleneck in state‐of‐the‐art solutions. Our experiments show that SHarP uses a constant amount of controller buffer, irrespective of the time taken to migrate the VNF state.

MIGRATE: Mobile Device Virtualisation Through State Transfer

“…However, the times cannot be compared to our results, given that this work focuses on the time the system is out during the migration, and our solution focused on eliminating this issue by maintaining the old VNF until the new one is ready. In [19], the authors mainly focus on an SDN-based migration of traffic through different VNFs, attending to the reduction of packet buffering in the SDN controller. MIGRATE does not impose the controller the need to buffer packets during the handover, since packets are addressed towards the old VxF until the new one is ready; however, some reference numbers regarding the migration time can be found.…”

“…The work in [18] proposes a solution to choose one or the other approach to meet application requirements, given that a vertical migration could imply significant cuts in the service. A solution to the loss of packets in the VNF migration process is given in [19] with SDN re-routing and minimising caching of messages addressed to the old VNF placement. However, a limited testbed is used to particularly evaluate the performance of the migration procedure using SDN, without involving the management of virtualisation resources with MANO capabilities.…”

Key Challenges, Drivers and Solutions for Mobility Management in 5G Networks: A Survey

“…Another example is the mechanisms used for making handover decisions, known as handover decision algorithms [59][60][61][62][63]. Protocols are also applied for rerouting data or voice calls to the new routing path, known as mobile routing protocols [64,65].…”