Design, Simulation and FPGA Implementation of a Novel Router for Bulk Flow TCP in Optical IP Networks (2011)

Architecture of a novel optical router is designed in RTL and implemented in FPGA for the use of bulk flow TCP in optical IP networks. Various functional blocks of optical router like fabrication of flow from the incoming packets, processing the flow for routing process, contention resolution, buffering the packet or flow based on the wavelength and channel availability and transmission of the flow for destination have been successfully designed in RTL and implemented in FPGA. The numbers of slices utilized by various flow stages have also been simulated. The proposed optical router is tested for its performance in terms of frequency of operation and the area of utilization by various functional units. We have also implemented the central control unit for this optical router. From the observation it is found that in steady state, the optical router for bulk flow TCP exhibits better performance in terms of congestion behavior and wavelength aware flow to form a global optical network infrastructure. Index Terms - Bulk flow TCP, contention resolution, Field Programmable Gate Arrays (FPGA), Optical packet switching (OPS), Time-To-Live (TTL), variable-sized packets, wavelength conversion, Optical router. conventional routers. Asynchronous optical switching and variable-length packets in the optical domain gaining momentum in the recent past (3-5) are due to optical switching and variable-length packets in the optical domain gaining momentum in the recent past (3-5) are due to wider availability of bandwidth and minimized loss rate. It greatly simplifies the optical router system by eliminating the needs for flow synchronization and optical-electrical-optical (O/E/O) conversion. In addition, it reduces processing overhead and bandwidth loss due to the segmentation and assembly of variable-length packets at the optical router node. At the same time, it also poses new challenges for designing the optical router to support asynchronous, flow based switching process. The analysis for heavy data transfer rate is of incredibly important to fulfill the ever increasing network traffic (6-8). Data transmitting protocols like TCP/IP, UDP and asynchronous Transfer Mode (ATM) are considered for higher transmission rate. Among all the protocols, TCP plays major role in the higher data transfer rate. In order to get the higher data transfer rate, various parameters are to be concentrated. They are, channel capacity or bandwidth, number of nodes in the network, number of electro optical converters present in the network, data transfer rate in each node, various network components and some quality of Service (QoS) parameters. The corrupted flow, packet out of order, delay in arriving the packet at the destination which causes unnecessary retransmission of packets, small window regime etc., are some of the limitations to the electronic band width resources. In order to utilize the enormous bandwidth available in the optical domain, an all optical networks have to be developed. Many researchers (9) are working in this area for the efficient utilization of the optical bandwidth. The wider bandwidth available with the optical domain may optimally be utilized by a modification in the existing TCP structure such that the packets are assumed to have very limited time for processing in the router. The reported work (10) suggested that the packets can be consolidated as a flow and hence the size can be increased for flow and the time required for processing of flow in the router can be minimized to a larger extent. This technique has a uniform delay, very flexible and scalable routing and it also produces very good throughput and contention resolution (11). A novel optical router capable of accepting and processing bulk flow TCP has to be designed and implemented which will receive the flow and performs the routing operation. The flow size in Bulk flow TCP in the proposed work is five to seven times larger than the conventional packet size to maintain the order of packets. The proposed router unit which has been designed such that the