Seamless Elasticity in NFV Environments with Heterogeneous Hardware Infrastructures

For the purpose of scale in/out operations or instance relocation, state migration mechanisms for virtualized network functions (VNFs) are required. Besides the naive "stop-transfer-start" approach, which commonly leads to serious service interruption, techniques for "seamless" state migration like VM memory delta transmission are in use for a while now, and recently, mechanisms like deterministic replay or packet duplication have been proposed to cope with the commonly high I/O load of VNFs.

In this project, we have designed and now evaluate a novel mechanism that only transfers "statelets", byte vectors that only carry the information in a packet relevant for state change, instead of duplicated packets with unnecessary payload. The statelets allow a full deterministic replay at the destination, but reduce the dataplane utilization for state synchronization by up to 96%.

With the network processors, we plan to evaluate state migration and elastic redistribution between heterogeneous NF instance types (e.g. x86-based PCs and network processors), depending on the current performance demand. In a related sub-project, we also evaluate if and how devices (cards/switches) with NPUs could be also used to pre-split flows into their simple (accelerated) or complex (x86/ARM) part on the dataplane.

Leonhard Nobach