  Network Function Virtualization (NFV) enables service providers to maximize
the business profit via resource-efficient QoS provisioning for customer
requested Service Function Chains (SFCs). In recent applications, end-to-end
delay is one of the crucial QoS requirement needs to be guaranteed in SFC
deployment. While it is considered in the literature, accurate and
comprehensive modeling of the delay in the problem of maximizing the service
provider's profit has not yet been addressed. In this paper, at first, the
problem is formulated as a mixed integer convex programming model. Then, by
decomposing the model, a two-level mapping algorithm is developed, that at the
first level, maps the functions of the SFCs to virtual network function
instances; and in the second level, deploys the instances in the physical
network. Simulation results show that the proposed approach achieves a near
optimal solution in comparison the performance bound obtained by the
optimization model, and also superiors the existing solutions.
