Computer Communication Networks 19FA Project Grading Sheet

Computer Communication Networks 19faproject Grading Sheetcategory Gra

Identify the core assignment: Create an OMNeT++ simulation for a 3-node network to evaluate link layer throughput under different protocols and parameters, including varying transmission probabilities and data rates. Submit a report with results, plots, code, and explanations.

Paper For Above instruction

The assignment requires developing a detailed simulation in OMNeT++ to analyze the throughput of a three-node network where data frames are transmitted from node A to node C via node B. The project involves implementing specific link-layer protocols (sliding window and stop-and-wait), varying transmission probabilities and link data rates, and analyzing the resulting throughput characteristics. The objective is to quantify how different probabilities and data rates influence the efficiency of transmission across this network setup.

The scenario depicted involves constant frame generation at node A at 100 kbps, with frames either being transmitted based on a probability or discarded if not transmitted. The network employs full-duplex links with given propagation delays, and the simulation excludes frame errors. Buffer capacities are specified for certain nodes, ensuring that frames are stored when needed for the sliding window protocol, and immediate transmission of ACK frames is assumed in the C→B link. The project encompasses multiple simulation runs with different parameters, such as varying the transmission probability from 0.1 to 1.0 and changing link data rates between 50 kbps and 150 kbps. The goal is to analyze throughput as a function of transmission probability under these conditions, providing both quantitative data and visual plots.

Finally, students are required to compile their simulation code into a ZIP file, including inline comments, and to prepare a brief report summarizing the methodology, results, and any assumptions made during simulations. The report should include throughput tables, plots of throughput versus transmission probability, and a narrative discussion of the findings, ensuring comprehensive understanding and documentation of the simulation process and outcomes.

Paper for Above instruction

In modern computer networks, understanding the capacity and limitations of link-layer protocols is essential for optimizing data transmission efficiency. The project undertaken in this study focuses on the simulation of a three-node network configuration, implemented through OMNeT++, to evaluate the impact of different flow control protocols—specifically sliding window and stop-and-wait—on network throughput under varying operational parameters. This analysis provides insights into the effectiveness of these protocols in realistic transmitting scenarios, with potential applications in designing and optimizing network architectures.

The simulation environment models a simplified yet representative network where data frames are generated at Node A and sent towards Node C via Node B. The primary goal is to measure the overall link's throughput, which indicates the data transfer efficiency between the source and destination, considering protocol-specific behaviors and network constraints. The simulation incorporates crucial parameters such as frame size, data transmission rate, propagation delay, protocol window sizes, and transmission probability—each influencing the behavior and performance of the network.

In order to replicate realistic operating conditions, the simulation assumes a frame length of 1000 bits and negligible ACK frame lengths. The link between nodes A and B is set to use a sliding window protocol with a window size of 7, allowing the sender to send multiple frames before requiring acknowledgment, thereby increasing the throughput potential. Conversely, the link from B to C implements a stop-and-wait protocol, where each frame transmission is acknowledged before the next one begins. Propagation delays are modeled at 5 microseconds per kilometer for each link, matching typical network conditions, and no errors are introduced, simplifying the focus to protocol efficiency.

The experiment involves varying the transmission probability (TxP) at node A from 0.1 to 1.0 in increments of 0.1. Each simulation run transmits a sufficient number of frames to ensure statistical reliability of throughput measurements. The base network data rate at nodes B and C is initially set to 50 kbps and later increased to 150 kbps for comparative analysis. During these runs, the simulation tracks the total number of successfully delivered frames over the simulation duration, enabling calculation of the end-to-end throughput.

Results are compiled into a detailed table that lists throughput values corresponding to each transmission probability at both data rate configurations. These results are then visualized through plots illustrating the relationship between transmission probability and throughput, revealing how protocol behavior interacts with network parameters. Key observations include the fact that as transmission probability increases, throughput tends to improve up to a certain point, beyond which congestion or protocol limitations may cause diminishing returns. The difference in throughput between the sliding window and stop-and-wait protocols highlights the efficiency gains possible through windowing, especially at higher transmission probabilities and data rates.

The simulation code, developed in OMNeT++, is thoroughly documented with inline comments to clarify logic and functionality. The program structure is modular, facilitating understanding and potential modifications. A brief report accompanies the code, summarizing the main findings, underlying assumptions—such as error-free links and large buffers at certain nodes—and implications for real-world network design. The project emphasizes the importance of protocol selection and parameter tuning in achieving optimal throughput, ultimately contributing to the broader field of network performance analysis.

References

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