A study of service function chaining towards the hybrid network functions

What is it about?

In the Service-Function-Chaining (SFC) enabled networks, various sophisticated policy-aware network functions, such as intrusion detection, access control and unified threat management, can be realized in either physical middleboxes or virtualized network function (VNF) appliances. In this paper, we study the service chaining towards the hybrid SFC clouds, where both physical appliances and VNF appliances provide services collaboratively. In such hybrid SFC networks, the challenge is how to efficiently steer the service chains for traffic demands while matching their individual policy chains concurrently such that a utility associated with the total admitted traffic rate and the induced overheads can be maximized.

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Why is it important?

The contributions of our study can be summarized as follows: (a) In the hybrid SFC networks, we study a joint service-function appliance deployment and routing orchestration problem with the objective to maximize a weighted utility, which positively associates with the total admitted traffic rates over a specified set of target sessions, reversely relates to the penalty of both routing and NFV market budget. (b) We find such problem has not been well solved so far. We then design a polynomial near-optimal approximation algorithm to solve this problem using the Markov approximation technique. The approximation property of the proposed algorithm is also proved. (c) Simulation results show that our proposed approach can yield a near-optimal solution in a small-scale network, and outperforms benchmark algorithms significantly in a fat-tree datacenter network.

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