Microsoft Corporation
Network Policy and Flow State Save/Restore for Highly Available Servicing

Abstract:

Described herein is a system and method for flow state save/restore of a virtual filtering platform. A first instance of a driver manages policy and flow state for ongoing flows between client device(s) and virtual machine(s). The virtual filtering platform is transitioned from the first instance of a driver to a second instance of the driver by serializing the policy and state for the ongoing flows on the first instance of the driver using a one pass algorithm. The serialized policy and state for the ongoing flows can be de-serialized with the ongoing flows re-established and/or reconciled on the second instance of the driver in accordance with the de-serialized policy and state for the plurality of ongoing flows. In some embodiments, a memory management technique can use a single operating system memory allocation call to allocate memory for the transition, with the technique managing utilization of the allocation memory.