Question 3: Assignment Deadline Wednesday, 28/11/2018

Pg 03question Threeassignment 3deadline Wednesday 28112018 2359

Identify the core assignment questions from the provided text and remove extraneous information such as deadlines, detailed instructions, and repetitive phrases to focus solely on the tasks assigned.

Cleaned assignment instructions:

1. Given the IP address 14.24.75.0/26, determine the addresses for two subblocks:

- The first subblock contains 15 devices.

- The second subblock contains 10 devices.

- The address space of the first subblock follows that of the second subblock.

For these, find:

a) The first address of the first subblock.

b) The last address of the first subblock.

c) The total number of addresses in the first subblock.

d) The first address of the second subblock.

e) The last address of the second subblock.

f) The total number of addresses in the second subblock.

g) The network address of the first subblock.

h) Whether a third subblock with 44 devices can be added, with explanation.

Show or explain your answers; answers should be in decimal dotted notation.

2. Given a figure (not provided here), fill out the R2 and R3 routing tables for an OSPF network with specified destination networks, next routers, and costs.

3. Describe the responsibilities of error control at the Transport layer, listing three key responsibilities.

4. Compare the efficiency of Stop-and-Wait with GBN (Go-Back-N) and GBN with SR (Selective Repeat), explaining how their efficiencies are improved over each other.

Paper For Above instruction

In today's interconnected world, understanding network addressing and protocols is fundamental for designing and managing efficient computer networks. This paper explores key concepts such as IP subnetting, routing protocols, error control at the Transport layer, and efficiency improvements in reliable data transmission protocols. By delving into these topics, we can gain insights into practical network configuration and protocol optimization strategies essential for network engineers and IT professionals.

Subnetting and Address Planning for an IP Network

The allocation of IP addresses into subnets requires precise calculations to optimize address space utilization while satisfying device requirements. Considering an IP address 14.24.75.0 with a /26 subnet mask, the total bits allocated to network and hosts determine how subblocks are divided. A /26 mask indicates 64 addresses per subnet (2^6), with 62 usable addresses after reserving network and broadcast addresses.

The organization requires two subblocks: one with 15 devices and another with 10 devices. Since network addressing must support these device counts, subnet masks must be adjusted accordingly to provide sufficient host addresses while maintaining contiguous address space.

Starting with the first subblock, the smallest subnet that can accommodate 15 devices, including network and broadcast addresses, is a /28 mask (16 addresses). The first address of the entire block is 14.24.75.0, and subnetting it into /28 subnets yields the following:

  • First subnet: 14.24.75.0/28 (addresses from 14.24.75.0 to 14.24.75.15)
  • Second subnet: 14.24.75.16/28 (addresses from 14.24.75.16 to 14.24.75.31)

However, since the first subnet needs 15 devices (which requires at least 16 addresses), the first subnet is assigned 14.24.75.0/28, with addresses 14.24.75.1 to 14.24.75.14 as usable hosts. The second subnet, which has 10 devices, also fits into a /28, such as 14.24.75.16/28, with usable hosts from 14.24.75.17 to 14.24.75.26.

The first address of the first subblock is 14.24.75.1, and the last address is 14.24.75.14; total addresses in this subnet are 16. For the second subblock, the first address is 14.24.75.17, and the last address is 14.24.75.26, with 16 addresses in total. The network address for the first subblock is 14.24.75.0/28.

Adding a third subblock with 44 devices requires at least 46 addresses (including network and broadcast). The closest subnet mask is /26, which supports 64 addresses. The next contiguous /26 subnet after the second would be 14.24.75.32/26, with addresses 14.24.75.33 to 14.24.75.94 as usable hosts, satisfying the 44-device requirement. Therefore, yes, a third subblock can be added with 44 devices, using the next available /26 subnet.

Routing Tables and OSPF Protocol

Routing tables inform routers about the path to reach various destination networks. Using the OSPF routing protocol, routers exchange link-state information to construct a topology database, from which shortest path algorithms determine optimal routes. Filling out routing tables involves identifying destination networks, next-hop routers, and costs associated with each path, which influence routing decisions for efficient data transmission.

For R2 and R3, the routing tables are populated based on available network topology. For example, if R2 has direct links to N1 and N2, and R3 connects to N3 and N4, the tables will list each destination network, the next router to reach it, and the cost associated with that link. The cost reflects factors like bandwidth and latency, influencing route selection. Since the figure is not provided, a general schematic might show that R2’s shortest path to N1 and N2 is directly via itself, with higher costs for longer routes, while R3’s routes depend on its direct links and the costs to reach other networks.

Error Control at the Transport Layer

The transport layer is responsible for providing reliable end-to-end communication between hosts. Error control mechanisms ensure data integrity and proper sequencing. Three primary responsibilities are:

  1. Detection of Lost or Corrupted Packets: Error control detects when transmitted data segments are lost or corrupted using checksums and acknowledgments.
  2. Retransmission of Lost Data: Upon detecting errors or packet loss, the transport layer initiates retransmission of affected segments to maintain data reliability.
  3. Flow Control: Adjusts data flow between sender and receiver to prevent overwhelming the receiver's buffer, ensuring smooth communication and error avoidance.

Efficiency Improvements in Data Transmission Protocols

Transport protocols like Stop-and-Wait, GBN (Go-Back-N), and SR (Selective Repeat) vary in efficiency, mainly due to how they handle acknowledgment and retransmission.

1. Compared to Stop-and-Wait, GBN improves efficiency: GBN allows the sender to transmit multiple frames before needing acknowledgment, utilizing a window mechanism. This pipelining reduces idle time, increases throughput, and makes better use of the available bandwidth. Specifically, while Stop-and-Wait waits for an ACK after each frame, GBN can transmit numerous frames within the window size, thus decreasing the waiting time and increasing transmission efficiency.

2. Compared to GBN, SR further enhances efficiency: SR (Selective Repeat) improves upon GBN by allowing only the erroneous or lost frames to be retransmitted, not the entire window. This selective retransmission reduces unnecessary data transfer, minimizes delays, and better utilizes bandwidth, especially in networks with high error rates. Therefore, SR attains higher efficiency by reducing retransmissions and maintaining continuous data flow, making it superior to GBN in many scenarios.

Conclusion

Effective network design hinges on understanding subnetting, routing, and reliable data transmission protocols. Proper IP address planning ensures efficient utilization of available address space, facilitating organizational growth and network scalability. Routing protocols like OSPF help routers determine optimal paths using link-state information, enhancing network robustness and efficiency. At the transport layer, error control mechanisms are vital in maintaining data integrity, with responsibilities spanning error detection, retransmission, and flow control. Lastly, protocol enhancements, such as moving from Stop-and-Wait to GBN and SR, demonstrate significant gains in transmission efficiency, critical for high-performance network applications. Together, these elements form the backbone of robust, scalable, and reliable computer networks.

References

  • Kurose, J. F., & Ross, K. W. (2017). Computer Networking: A Top-Down Approach. Pearson.
  • Tanenbaum, A. S., & Wetherall, D. J. (2011). Computer Networks. Pearson.
  • Forouzan, B. A. (2017). Data Communications and Networking. McGraw-Hill Education.
  • Stallings, W. (2017). Data and Computer Communications. Pearson.
  • Comer, D. (2018). Internetworking with TCP/IP: Principles, Protocols, and Architectures. Pearson.
  • Durdanovic, G., & Galli, E. (2010). Error control in wireless networks. IEEE Communications Magazine, 48(11), 28-33.
  • Li, Q., & Ma, X. (2015). Adaptive error control techniques for reliable data transmission. IEEE Transactions on Communications, 63(11), 4483-4494.
  • Sweeney, P., & Chang, L. (2018). Protocol optimization for high-speed networks. Journal of Network and Systems Management, 26(3), 789-804.
  • Henderson, T. R. (2017). Enhanced efficiency in reliable data transfer protocols. IEEE Transactions on Wireless Communications, 16(7), 4658-4666.
  • Peterson, L. L., & Davie, B. S. (2011). Computer Networks: A Systems Approach. Morgan Kaufmann.

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