## 1 Introduction
### Related Work  
In the following, research works dealing with service management and QoS assurance in IP/optical networks are outlined. These works will be the basis for the approach proposed in this paper. [PERSON] _et al._ developed the concept of self-management [4] to achieve traffic-driven lightpath provisioning. Their goal is to select the IP flows more suitable to be offloaded to lightpaths in IP/optical networks, and also to establish and release these lightpaths in an automated manner. The core to this approach consists in monitoring network data to detect elephant flows based on a set of parameters to decide on transporting these flows at the optical layer in a rapid, automated manner, while the other flows remain at the IP layer. The concept of impairment-aware routing and wavelength assignment (IA-RWA) was introduced in the late 90s by [PERSON] _et al._ to assure QoS in the establishment process of new lightpaths by means of including information of the optical layer into the routing and resource assignment decisions [5]. That is, the estimation of the impairments experienced by the optical signal transporting data over a lightpath is included in the lightpath establishment process to help assure QoS by anticipating the degradation that data would suffer if the lightpath was established.  
This is important because lightpaths transport high amounts of data, which means that establishing too impaired lightpaths may result in enormous data loss, and hence in severe QoS violations. Related with that, non-intrusive monitoring schemes are also being investigated under the framework of optical performance monitoring [6]. This is especially relevant in all-optical (transparent) networks, where data is transported in the optical domain from the network's ingress to egress without undergoing electro-optical conversions in the intermediate nodes, and QoS needs to be assured without having access to digital information about the optical signals being transported in the network.  
The application of a service plane to optical networks was first proposed by the Service Oriented Optical Network (SOON) project in 2005 [7]. This proposal improved the ITU-T standard automatic switched transport network (ASTN) architecture [8] by introducing an additional functional layer called service plane, which contained the intelligence for service provisioning and provided abstraction from transport-related implementation details. Further details are provided in Section 2.  
This paper reviews the concepts of service-oriented and self-managed networks. Then, it relates them to propose an integrated approach to assure QoS by offering flow-aware networking in the sense that traffic demands will be anticipated in a suitable way, lightpaths will be established with the cooperation between the IP and optical layers to achieve impairment-awareness, and complex services will be decomposed into optical connections so that the above techniques can be employed to assure QoS for any service. The remainder of the paper is organized as follows. Section 2 overviews the architectures of service-oriented IP/optical networks and self-managed IP/optical networks. In Section 3, we review the main concepts of QoS in IP/optical networks in terms of the relation between QoS and the previous architectures (service-oriented and self-managed networks). Section 4 proposes an integrated approach for QoS assurance in IP/optical networks involving anticipation of traffic demands to offload elephant flows to the optical layer, also decomposing complex services into a series of connection requests, and then establishing lightpaths incorporating IA-RWA. Finally, in Section 5 we draw conclusions and outline future work.