Traffic steering of middlebox policy chain based on SDN

The delivery of services typically requires packets to be steered through a sequence of middleboxes to improve network security and performance. One constraint on the deployment of services is that middleboxes are tightly coupled to the physical network topology. As a result, ensuring successful deployment requires error-prone and complex low-level configurations. Software-Defined Networking (SDN) can eliminate the need to configure network devices manually to deploy services. However, in terms of steering middlebox-specific traffic in data plane, applying the existing capabilities supported by OpenFlow protocol may lead to incorrect forwarding decisions when there is a loop in the route used to steer traffic. In this paper, we present an implementation using tagging to discriminate different instances of the same packet arriving at the same ingress port on the same switch (i.e. the existence of the loop). Moreover, we propose an algorithm to judge the existence of the loop in a physical sequence of switches and decide which switches are responsible for adding tags. The experimental result demonstrates that our implementation can properly steer traffic through a specific sequence of middleboxes even when there are loops in forwarding path.