Research On Resource Allocation For Hybrid Data Center Switching Layer

In the era of big data, the network traffic showed a blowout growth, the network traffic model is changing from the traditional north-south traffic to an east-west one. The data center network architecture evolves from the traditional electrical packet switching network architecture to the optical hybrid network architecture. Due to the centralized control of the control plane, the software defined network is widely used in optoelectronic hybrid data centers. This paper will focus on network topology of software-defined hybrid data center, control plane interoperability and the joint scheduling of resources to carry out in-depth study.First, in the architecture of software-defined hybrid data center, a flat ring topology is designed for the data plane. In the topology, in order to avoid optical switching equipment reconfiguration delay which caused network packet loss and jitter, a buffer layer is designed to provide timely access to the packet switching link. Software-defined hybrid network belongs to the heterogeneous network, there are difficulties in scheduling mechanism and control plane interoperability. In order to dynamically assign and reconfigure the optical/electrical routing path and optimize the optical/electrical resource allocation, a control scheme which consists of two parallel rounds including the new request handle round which is used to quickly process the new incoming request and the hybird resource optimize round that periodically optimizes the hybird optical/electrical network resource is proposed in this paper. To validate the proposed control scheme, a hybird optical/electical routing algorithm used for handling elephant/mice flows is also proposed in this paper. Experimental results show that the proposed control scheme can effectively manage the hybird network. To improve the survivability of passive optical network,this paper implements an optical link fault monitoring and automatic fault recovery method based on OpenFlow. The method uses the detection packet to detect the link. When the packet is lost, SDON controller automatically calls Routing algorithm to calculate the recovery route path, and reconfigure the switches.Second, combining with SDN, this paper proposes a transmission system based on block-interleaving frequency division multiplexing access (B-IDFMA) technology for the low utilization rate of physical layer in optical network in data center. An erbium doped fiber amplifier (EDFA) is adopted to amplify the optical signal at the sending terminal and optimized channel estimation algorithms are employed at the receiver.25 Gb/s double-sided band (DSB)B-IFDMA PON is demonstrated over 100 km fiber by simulation. Five kinds of channel estimation algorithms are used to improve transmission performance. Simulation results show that the Linear Minimum Mean Squared Error (LMMSE) estimator has better performance and lower computational complexity than the others. Compared with original Least Square (LS)channel estimation, the receiver sensitivity is improved 1.6dB at bit error rate of 10’3.