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2 Virtual Traffic Classifier
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8 The virtual Traffic Classifier VNF [1], comprises in the current version of
9 1 VNFC [2]. The VNFC contains both the Traffic Inspection module, and the
10 Traffic forwarding module, needed to run the VNF. The exploitation of DPI
11 methods for traffic classification is built around two basic assumptions:
13 (i) third parties unaffiliated with either source or recipient are able to
14 inspect each IP packet’s payload and
15 (ii) the classifier knows the relevant syntax of each application’s packet
16 payloads (protocol signatures, data patterns, etc.).
18 The proposed DPI based approach will only use an indicative, small number of
19 the initial packets from each flow in order to identify the content and not
22 In this respect it follows the Packet Based per Flow State (PBFS).
23 This method uses a table to track each session based on the 5-tuples
24 (src address,dest address,src port,dest port,transport protocol)
25 that is maintained for each flow.
30 Traffic Inspection: The process of packet analysis and application
31 identification of network traffic that passes through the vTC.
33 Traffic Forwarding: The process of packet forwarding from an incoming
34 network interface to a pre-defined outgoing network interface.
36 Traffic Rule Application: The process of packet tagging, based on a
37 predefined set of rules. Packet tagging may include e.g. ToS field
43 The Traffic Inspection module is the most computationally intensive component
44 of the VNF. It implements filtering and packet matching algorithms in order to
45 support the enhanced traffic forwarding capability of the VNF. The component
46 supports a flow table (exploiting hashing algorithms for fast indexing of
47 flows) and an inspection engine for traffic classification.
49 The implementation used for these experiments exploits the nDPI library.
50 The packet capturing mechanism is implemented using libpcap. When the DPI
51 engine identifies a new flow, the flow register is updated with the
52 appropriate information and transmitted across the Traffic Forwarding module,
53 which then applies any required policy updates.
55 The Traffic Forwarding moudle is responsible for routing and packet forwarding.
56 It accepts incoming network traffic, consults the flow table for classification
57 information for each incoming flow and then applies pre-defined policies
58 marking e.g. type of Service/Differentiated Services Code Point (TOS/DSCP)
59 multimedia traffic for QoS enablement on the forwarded traffic.
60 It is assumed that the traffic is forwarded using the default policy until it
61 is identified and new policies are enforced.
63 The expected response delay is considered to be negligible,as only a small
64 number of packets are required to identify each flow.
72 run the build.sh with root privileges
77 sudo ./pfbridge -a eth1 -b eth2
84 Development Environment
85 =======================