human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "three tier network architecture to mitigate ddos attacks on hybrid cloud environments"
  Abstract: Connecting the wired and wireless networks particularly the Mobile ad hoc Network is interesting in real world situations due to its usefulness and practicality. Different mechanisms have been proposed to integrate MANETs and the Internet. These strategies differ in gateway discovery mechanism, cell switching criteria, ad hoc routing protocol.In this paper, Mobile-IP is integrated with Hierarchical Cluster-Head Gateway Switch Routing (CGSR) Protocol to provide Internet access to the mobile node of the ad hoc Network. This paper discusses a mechanism for selecting an alternate route in case if the Cluster Head is unable to forward the packets to the destination. The proposed framework provides bi-directional connectivity between the MANET and the Internet nodes. A detailed performance comparison is made between the proposed approach and the other three-tier strategies based on mobility of cluster heads and cluster gateways and other network parameters. The experimental results indicate that the proposed architecture has better packet delivery ratio, end-end delay and mobile node-gateway connectivity ratio for providing full bi-directional connectivity.

Question: Please tell me which class the center node belongs to. The 40 classes are: cs.NA(Numerical Analysis), cs.MM(Multimedia), cs.LO(Logic in Computer Science), cs.CY(Computers and Society), cs.CR(Cryptography and Security), cs.DC(Distributed, Parallel, and Cluster Computing), cs.HC(Human-Computer Interaction), cs.CE(Computational Engineering, Finance, and Science), cs.NI(Networking and Internet Architecture), cs.CC(Computational Complexity), cs.AI(Artificial Intelligence), cs.MA(Multiagent Systems), cs.GL(General Literature), cs.NE(Neural and Evolutionary Computing), cs.SC(Symbolic Computation), cs.AR(Hardware Architecture), cs.CV(Computer Vision and Pattern Recognition), cs.GR(Graphics), cs.ET(Emerging Technologies), cs.SY(Systems and Control), cs.CG(Computational Geometry), cs.OH(Other Computer Science), cs.PL(Programming Languages), cs.SE(Software Engineering), cs.LG(Machine Learning), cs.SD(Sound), cs.SI(Social and Information Networks), cs.RO(Robotics), cs.IT(Information Theory), cs.PF(Performance), cs.CL(Computation and Language), cs.IR(Information Retrieval), cs.MS(Mathematical Software), cs.FL(Formal Languages and Automata Theory), cs.DS(Data Structures and Algorithms), cs.OS(Operating Systems), cs.GT(Computer Science and Game Theory), cs.DB(Databases), cs.DL(Digital Libraries), cs.DM(Discrete Mathematics). Directly output the class name.

gpt: cs.NI(Networking and Internet Architecture)