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: "an analysis of the skype peer to peer internet telephony protocol"
  Abstract: Skype is a peer-to-peer VoIP client developed by KaZaa in 2003. Skype claims that it can work almost seamlessly across NATs and firewalls and has better voice quality than the MSN and Yahoo IM applications. It encrypts calls end-to-end, and stores user information in a decentralized fashion. Skype also supports instant messaging and conferencing. This report analyzes key Skype functions such as login, NAT and firewall traversal, call establishment, media transfer, codecs, and conferencing under three different network setups. Analysis is performed by careful study of Skype network traffic.

Connected through hyperedge HE-1 (induced by source paper "peer to peer based social networks a comprehensive survey"):
  with members:
    - "privacy and security in online social networks a survey"
    - "a survey of p2p multidimensional indexing structures"
    - "hskip a self stabilizing overlay network for nodes with heterogeneous bandwidths"
    - "twister a p2p microblogging platform"
    - "decent a decentralized architecture for enforcing privacy in online social networks"
    - "supernova super peers based architecture for decentralized online social networks"
    - "skip webs efficient distributed data structures for multi dimensional data sets"
    - "attrition defenses for a peer to peer digital preservation system"

Connected through hyperedge HE-2 (induced by source paper "self healing protocols for connectivity maintenance in unstructured overlays"):
  with members:
    - "on the topology maintenance of dynamic p2p overlays through self healing local interactions"
    - "searching in unstructured overlays using local knowledge and gossip"
    - "resilience of dynamic overlays through local interactions"
    - "publish subscribe systems via gossip a study based on complex networks"
    - "lunes agent based simulation of p2p systems"

Connected through hyperedge HE-3 (induced by source paper "windows instant messaging app forensics facebook and skype as case studies"):
  with members:
    - "forensics acquisition and analysis of instant messaging and voip applications"
    - "a forensically sound adversary model for mobile devices"
    - "forensic taxonomy of popular android mhealth apps"
    - "privacy risks in mobile dating apps"

Connected through hyperedge HE-4 (induced by source paper "distributed computing on core periphery networks axiom based design"):
  with members:
    - "distributed computation of large scale graph problems"
    - "super fast distributed algorithms for metric facility location"
    - "optimal deterministic routing and sorting on the congested clique"
    - "tri tri again finding triangles and small subgraphs in a distributed setting"
    - "from caesar to twitter an axiomatic approach to elites of social networks"
    - "tight bounds for parallel randomized load balancing"
    - "the hardness of median in the synchronized bit communication model"

Connected through hyperedge HE-5 (induced by source paper "an open source p2p encrypted voip application"):
  with members:
    - "proposed video encryption algorithm v s other existing algorithms a comparative study"
    - "comparative study of qos parameters of sip protocol in 802 11a and 802 11b network"
    - "new security and control protocol for voip based on steganography and digital watermarking"

Connected through hyperedge HE-6 (induced by source paper "lp based covering games with low price of anarchy"):
  with members:
    - "resource buying games"
    - "near optimality in covering and packing games by exposing global information"
    - "a primal dual parallel approximation technique applied to weighted set and vertex covers"

Connected through hyperedge HE-7 (induced by source paper "ip over voice over ip for censorship circumvention"):
  with members:
    - "how china is blocking tor"
    - "censorspoofer asymmetric communication with ip spoofing for censorship resistant web browsing"

Connected through hyperedge HE-8 (induced by source paper "p2p iptv measurement a comparison study"):
  with members:
    - "rarest first and choke algorithms are enough"

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)