By pushing forward the high-level design of CellSDN,
SoftCell [2] presents a detailed scalable architecture design
to support fine-grained policies in cellular core networks.
With the controller handling low-level details such as
switch location and network identifier, SoftCell adopts a
set of service policies as a high level of abstraction based
on subscriber attributes and applications. The service policies
include priority, service action, and predicates. To
handle network dynamics and enable fine-grained policies
at scale, SoftCell achieves scalability by extending both the
control and data plane. In the control plane, SoftCell uses
local software agents to cache packet classifiers and policy
tags in order to reduce the load of the main controller. In
the data plane, SoftCell pushes packet classification to the
access switches and apply multi-dimensional forwarding
rule aggregation to minimize the state in the core network.