, as a deeper perception, is an integrated perception for all layers/levels of the network model in order to realize wholly controls and managements for operation, performance, security, guarantees, and also unexpected network faults or problems. Furthermore, cognition is a process of feedback cycle. Reference [53] introduces such a feedback cycle which can be depicted by Figure 6.2. Based on certain envi- ronment, a series of sequenced processes of observing, orienting, deciding, and acting will ultimately act on the original environment to help it update its status information, those of which involves performance, security, guarantees, and other aspects of the whole system. From the perspective of implementation, cognition is no longer a simple process of appending or expanding, instead, it is more likely to be a relocating, replanning, or redesignation for the network model. Scopes of cognition can be described by Table 6.1. Comparing the differences between perception and cognition, their relation is more apparent. The concepts of cognition include ones of perception, but for a wider scope and deeper understanding. The connotation of cognition covers not Overview of Cognitive NGSDP Model Observe Orient Environment Decide Figure 6.2 Feedback cycle of cognition. (Thomas, R.W., DaSilva, L.A., and MacKenzi, A.B. First IEEE International Symposium on New Frontiers in Dynamic Spectrum Access Networks, © 2005. IEEE.) Table 6.1 Cognition Scopes Layers Scopes Physical layer Be self-aware and adaptive of topology, links and basic devices. Network layer Be self-aware and adaptive of data packets, flows and protocols. Application layer Be self-aware and adaptive of business services and network behaviors, and also related security aspects, such as access controls and intrusion detections. Management layer Be self-aware and adaptive of managements, including distribution, management, monitoring of network resources, management of network performances and securities, management and controls of SLA (Service Level Agreement)