Bandwidth-Guaranteed Path Planning Based On OpenFlow In Inter-datacenter Networks

With the widespread use of different-scaled datacenters,cloud service providers synchronize data between different datacenters and provide online services with different functions.The resulting massive data is transferred in the inter-datacenter network,giving rise to link blocking during the transmission peak and overall low link bandwidth utilization.Moreover,different services have different requests for bandwidth,real-time performance,etc.It makes the resource allocation and path planning extremely complex in the inter-datacenter network.Software-Defined Networking(SDN),a novel network architecture rising in recent years,uses OpenFlow as its core protocol.In the conventional network architecture,the configuration of each data switching device(e.g.,router or switch)is relatively independent,and the process to modify the configuration is complicated and inflexible.Meanwhile,OpenFlow allows remote controllers to determine the data routing path via managing the OpenFlow switches in the network.Therefore,the idea of control and forwarding separation can be used to make traffic management more flexible and multi-granular.In view of this,this thesis proposes a path planning scheme named OpenFlow-based path planning with bandwidth guarantee(OPPBG),which applies the separation of the network management and data forwarding supported by the OpenFlow protocol.Meanwhile,two routing algorithms applied in OPPBG – Routing with Bandwidth Guarantee(RBG)and Routing with Bandwidth Guarantee and considering Priority(RBG_PRI)are also proposed in this thesis.When a flow arrives,OPPBG collects the real-time link status of network and returns a virtual topology with sufficient remainder bandwidth.And then,the RBG algorithm calculates a shortest routing path for the flow.The simulation results show that the RBG-applied OPPBG achieves a lower packet loss rate and a higher bandwidth utilization in network performance when comparing with the traditional Shortest Path First scheme.Based on RBG,the thesis also takes the flow priority into consideration and proposes a modified algorithm named RBG_PRI,for solving the problem that kinds of services within the inter-datacenter network have different characteristics and different resources requests.RBG_PRI sets flow priorities according to the different demand for real-time processing or other factors,and it restricts the max link bandwidth usage by setting a threshold,aiming to reduce the packet loss rate of the flows with high priority.The OPPBG applied RBG_PRI is evaluated by simulation experiment,too.Results show that the network performance achieves anticipated goal in terms of packet loss rate of the high-priority flow and average packet loss rate.In order to manage network resource and carry out the OPPBG scheme more efficiently,a SDN management platform is implemented in the thesis.The platform is based on the northern interfaces of SDN controller and consists of topology accessing module,routing module and so on.