Fine-Grained and Distributed Traffic Monitoring Platform in Software-Defined Networks

Traffic engineering is an important issue for network operation. It is essential for most networks since it enables network operators and service providers to ensure efficient use of network resources and proper network performance for applications and services. Traffic engineering adapts the routing of traffic based on the network conditions and optimizes traffic demand and capacity such as big flow migrations, fine-grained QoS control, anomaly elimination. Therefore, it requires integrating of traffic monitoring and control capabilities in the network. However, in the past and current networks, network monitoring and control are conducted independently, and current monitoring techniques require separate hardware deployment or software configuration, making it hard to implement traffic engineering and other network management applications. Different monitoring techniques are used for monitoring networks such as sFlow, NetFlow, Simple Network Management Protocol (SNMP), and other telemetry tools. Though SNMP is integrated in most network devices, it limits counters to aggregate traffic for the whole switch and each of its interfaces, disabling insight into flow-level statistics necessary for fine-grained traffic engineering. While packet-sampling tools like sFlow and NetFlow mostly require separate hardware deployment for the flow collector and they are not integrated with existing control protocol/APIs in the networks. Therefore, existing monitoring techniques remain inflexibility and drawback to meet traffic engineering requirement. Recently, Software Defined Network (SDN) has been introduced to solve the drawbacks of network control and monitoring in current networks. SDN in general and OpenFlow as its current implementation instance in particular, provides a centralized visibility with global network and application information, a programmability without a need to handle individual network elements, and a traffic flow based controllability with flow table pipelines in OpenFlow switches making flow management more flexible and efficient. With these supports, traffic engineering mechanisms can be implemented flexibly and intelligently in SDN/OpenFlow compared to conventional approaches. For traffic monitoring functionality, SDN/OpenFlow employs a default monitoring mechanism that records statistics of flows using forwarding flow tables. This monitoring mechanism