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Big data - Concept and application for telecommunications                       5


            2)      Content transmission control between cache nodes of CDN in bDDN.

            The network plane in the bDDN is responsible for network control and adjustment. When the cache nodes
            are deployed in the bDDN, the network plane needs to enhance control of the overlay network between the
            cache nodes and control the data transmission between the cache nodes according to the network state.

            The big-data plane collects all data from the network infrastructure and analyses it according to the network
            data (including the network status forecast). When the CN1 wants to send a huge data volume to CN3 (which
            will take a long time), the big-data plane of bDDN computes and forecasts the physical link status between
            the routers in addition to forecasting the virtual link (overlay link) status between the cache nodes. If the
            virtual link is much better for the data transmission, the data are transferred over the virtual links. Figure 6-13
            depicts content transmission control between cache nodes of CDN in bDDN.




























                       Figure 6-13 – Content transmission control between the content delivery network
                                         cache nodes in big-data-driven networking

            6.13    Big-data-driven NAT devices detection

            For  a  number  of  reasons,  including  the  shortage  of  Internet  protocol  version  4  (IPv4)  addresses,  many
            locations are connected to the Internet by means of network address translation (NAT) devices. A NAT box
            uses a very small number of IP addresses – perhaps just one – but can act as a relay for many different hosts
            behind it. NAT hides the internal network structure from the external network. On one hand, it offers access
            to  illicit  terminal  facilities,  causing  potential  threats  to  the  network;  on  the  other  hand,  users  can  also
            privately share networks through NAT, which directly harm the interests of network operators. Effective
            detection of NAT devices plays an important role in network security and control, network operation and
            management.

            A big-data- and machine-learning-driven NAT devices detection method is shown in Figure 6-14. This is a kind
            of supervised machine-learning method for NAT device detection. First, the training set requires set-up. In
            order  to  identify  application  traffic  and  web  browser  traffic,  the  application  signature  Lib  and  the  web
            signature Lib are set up. The IP addresses of known NAT devices are collected, the network traffic is identified
            by matching traffic of known IP addresses and the application signature Lib or the web signature Lib. Then
            the identified traffic data are used as the training data for the C5.0 machine-learning algorithm. After training,
            the C5.0 algorithm acts as the detector to identify the IP as a NAT device or not. The features are chosen of
            application number (the application number of accessed by the IP), application type number (application are
            classified into types, e.g., video, shopping; the application type number is the number of different application
            types  that  the  IP  accessed),  application  duration  (the  time  duration  that  the  user  IP  accessed  the
            application),web browser times (the total number of times that the user IP accessed the web), web type
            number (webs are also classified into different types, .g., news web, sport web, business web) and web



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