  With the increasing demand for openness, flexibility, and monetization the
Network Function Virtualization (NFV) of mobile network functions has become
the embracing factor for most mobile network operators. Early reported field
deployments of virtualized Evolved Packet Core (EPC) - the core network
component of 4G LTE and 5G non-standalone mobile networks - reflect this
growing trend. To best meet the requirements of power management, load
balancing, and fault tolerance in the cloud environment, the need for live
migration for these virtualized components cannot be shunned. Virtualization
platforms of interest include both Virtual Machines (VMs) and Containers, with
the latter option offering more lightweight characteristics. The first
contribution of this paper is the implementation of a number of custom
functions that enable migration of Containers supporting virtualized EPC
components. The current CRIU-based migration of Docker Container does not fully
support the mobile network protocol stack. CRIU extensions to support the
mobile network protocol stack are therefore required and described in the
paper. The second contribution is an experimental-based comprehensive analysis
of live migration in two backhaul network settings and two virtualization
technologies. The two backhaul network settings are the one provided by
CloudLab and one based on a programmable optical network testbed that makes use
of OpenROADM dense wavelength division multiplexing (DWDM) equipment. The paper
compares the migration performance of the proposed implementation of
OpenAirInterface (OAI) based containerized EPC components with the one
utilizing VMs, running in OpenStack. The presented experimental comparison
accounts for a number of system parameters and configurations, image size of
the virtualized EPC components, network characteristics, and signal propagation
time across the OpenROADM backhaul network.
