This document summarizes different algorithms for adaptive retransmission in TCP. The original TCP specification uses an average of sample round-trip times (RTTs) to estimate the RTT and sets the timeout to twice the estimated RTT. The Karn/Partridge algorithm only measures RTT for original transmissions and uses exponential backoff for timeouts after retransmissions. The Jacobson/Karela algorithm calculates estimated RTT and deviation from it to set the timeout to the estimated RTT plus a factor times the deviation, allowing larger timeouts when variance is high.
Hello People.. Welcome to GURUKULA!!!
Have you ever thought that how the protocols that are required for the effective delivery of the messages from one place to anpther place take place in a real time internet..... This video explains about the concept called PROTOCOL LAYERING, where you can learn the way how the protocols are layered in such a way..
Simple examples are also used to make the concepts clean nd clear.
This video will help you to learn:
What is protocol layering in networks, OSI Model in Computer Networks, Layers of OSI Model, OSI Model, OSI Internet Module, OSI Layers and their Functions, Examples of OSI Models, 7 layers of OSI Models, Principles of Protocol Layering, Why layering the Protocols,
Thanks for Watching, Keep Supporting and Keep Sharing...
In this we discuss about DATA RATE LIMITS
Two theoretical formulas were developed to calculate the data rate:
Nyquist bit rate for a noiseless channel
BitRate = 2 * bandwidth * log 2 L
2: Shannon Capacity for a noisy channel
Capacity = bandwidth * log 2 (1 + SNR)
...............
PERFORMANCE (Network PERFORMANCE) :
Bandwidth: ( Bandwidth in Hertz and Bandwidth in Bits per Seconds) :
Throughput:
These above topics covered in this slide
Thanks You!
Cohen-Sutherland Line Clipping Algorithm:
When drawing a 2D line on screen, it might happen that one or both of the endpoints are outside the screen while a part of the line should still be visible. In that case, an efficient algorithm is needed to find two new endpoints that are on the edges on the screen, so that the part of the line that's visible can now be drawn. This way, all those points of the line outside the screen are clipped away and you don't need to waste any execution time on them.
A good clipping algorithm is the Cohen-Sutherland algorithm for this solution.
By,
Maruf Abdullah Rion
Hello People.. Welcome to GURUKULA!!!
Have you ever thought that how the protocols that are required for the effective delivery of the messages from one place to anpther place take place in a real time internet..... This video explains about the concept called PROTOCOL LAYERING, where you can learn the way how the protocols are layered in such a way..
Simple examples are also used to make the concepts clean nd clear.
This video will help you to learn:
What is protocol layering in networks, OSI Model in Computer Networks, Layers of OSI Model, OSI Model, OSI Internet Module, OSI Layers and their Functions, Examples of OSI Models, 7 layers of OSI Models, Principles of Protocol Layering, Why layering the Protocols,
Thanks for Watching, Keep Supporting and Keep Sharing...
In this we discuss about DATA RATE LIMITS
Two theoretical formulas were developed to calculate the data rate:
Nyquist bit rate for a noiseless channel
BitRate = 2 * bandwidth * log 2 L
2: Shannon Capacity for a noisy channel
Capacity = bandwidth * log 2 (1 + SNR)
...............
PERFORMANCE (Network PERFORMANCE) :
Bandwidth: ( Bandwidth in Hertz and Bandwidth in Bits per Seconds) :
Throughput:
These above topics covered in this slide
Thanks You!
Cohen-Sutherland Line Clipping Algorithm:
When drawing a 2D line on screen, it might happen that one or both of the endpoints are outside the screen while a part of the line should still be visible. In that case, an efficient algorithm is needed to find two new endpoints that are on the edges on the screen, so that the part of the line that's visible can now be drawn. This way, all those points of the line outside the screen are clipped away and you don't need to waste any execution time on them.
A good clipping algorithm is the Cohen-Sutherland algorithm for this solution.
By,
Maruf Abdullah Rion
This presentation features a walk through the Linux kernel networking stack covering the essentials and recent developments a developer needs to know. Our starting point is the network card driver as it feeds a packet into the stack. We will follow the packet as it traverses through various subsystems such as packet filtering, routing, protocol stacks, and the socket layer. We will pause here and there to look into concepts such as segmentation offloading, TCP small queues, and low latency polling. We will cover APIs exposed by the kernel that go beyond use of write()/read() on sockets and will look into how they are implemented on the kernel side.
ENHANCEMENT OF TCP FAIRNESS IN IEEE 802.11 NETWORKScscpconf
The usage of fixed buffers in 802.11 networks has a number of disadvantages associated with
it. This includes high delay, reduced throughput and inefficient channel utilisation. To
overcome this, a dynamic buffer sizing algorithm, the A* algorithm has been implemented at
the access point. In this algorithm buffer size is dynamically adjusted depending upon the
current channel conditions and hence delay is reduced and the throughput is maintained. But
in 802.11 networks with DCF collision avoidance mechanism, it creates significant amount of
unfairness between the upstream and downstream TCP flows, with clusters of upstream ACKs
blocking downstream data at the access point. Thus a variation of the Explicit Window
Adaptation (EWA) scheme has been used to regulate the queuing time of the upload clients by
calculating the feedback value at the access point. This creates fairness and increases the number of transmission opportunities for the downstream traffic
Fault tolerant wireless sensor mac protocol for efficient collision avoidancegraphhoc
In sensor networks communication by broadcast methods involves many hazards, especially collision. Several MAC layer protocols have been proposed to resolve the problem of collision namely ARBP, where the best achieved success rate is 90%. We hereby propose a MAC protocol which achieves a greater success rate (Success rate is defined as the percentage of delivered packets at the source reaching the destination successfully) by reducing the number of collisions, but by trading off the average propagation delay of transmission. Our proposed protocols are also shown to be more energy efficient in terms of energy dissipation per message delivery, compared to the currently existing protocol.
The performance of wireless ad hoc networks is impacted significantly by the way TCP reacts to lost packets. TCP was designed specifically for wired, reliable networks; thus, any packet loss is attributed to congestion in the network. This assumption does not hold in wireless networks as most packet loss is due to link failure. In our research we analyzed several implementations of TCP, including TCP Vegas, TCP Feedback, and SACK TCP, by measuring throughput, retransmissions, and duplicate acknowledgements through simulation with ns-2. We discovered that TCP throughput is related to the number of hops in the path, and thus depends on the performance of the underlying routing protocol, which was DSR in our research.
Comparison of TCP congestion control mechanisms Tahoe, Newreno and VegasIOSR Journals
The widely used reliable transport protocol TCP, is an end to end protocol designed for the wireline
networks characterized by negligible random packet losses. This paper represents exploratory study of TCP
congestion control principles and mechanisms. Modern implementations of TCP contain four intertwined
algorithms: slow start, congestion avoidance, fast retransmit, and fast recovery. In addition to the standard
algorithms used in common implementations of TCP, this paper also describes some of the more common
proposals developed by researchers over the years. We also study, through extensive simulations, the
performance characteristics of four representative TCP schemes, namely TCP Tahoe, New Reno and Vegas
under the network conditions of bottleneck link capacities for wired network
Comparison of TCP congestion control mechanisms Tahoe, Newreno and VegasIOSR Journals
Abstract: The widely used reliable transport protocol TCP, is an end to end protocol designed for the wireline networks characterized by negligible random packet losses. This paper represents exploratory study of TCP congestion control principles and mechanisms. Modern implementations of TCP contain four intertwined algorithms: slow start, congestion avoidance, fast retransmit, and fast recovery. In addition to the standard algorithms used in common implementations of TCP, this paper also describes some of the more common proposals developed by researchers over the years. We also study, through extensive simulations, the performance characteristics of four representative TCP schemes, namely TCP Tahoe, New Reno and Vegas under the network conditions of bottleneck link capacities for wired network. Keywords - Congestion avoidance, Congestion control mechanisms, Newreno, Tahoe, TCP, Vegas.
IMPACT OF CONTENTION WINDOW ON CONGESTION CONTROL ALGORITHMS FOR WIRELESS ADH...cscpconf
TCP congestion control mechanism is highly dependent on MAC layer Backoff algorithms that
predict the optimal Contention Window size to increase the TCP performance in wireless adhoc
network. This paper critically examines the impact of Contention Window in TCP congestion
control approaches. The modified TCP congestion control method gives the stability of
congestion window which provides higher throughput and shorter delay than the traditional TCP. Various Backoff algorithms that are used to adjust Contention Window are simulatedusing NS2 along with modified TCP and their performance are analyzed to depict the influence of Contention Window in TCP performance considering the metrics such as throughput, delay, packet loss and end-to-end delay
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
2. Adaptive Retransmission
TCP guarantees the reliable delivery of data, it retransmits each
segment if an ACK is not received in a certain period of time.
TCP set this timeout as a function of RTT it expects between the
two ends of the connection.
But in Internet RTT between any two hosts will vary over time.
Choosing approximate value is not easy. To address this problem
TCP uses an adoptive retransmission algorithm.
Original Algorithm:
• Originally described in TCP specification.
• Running average of RTT and then compute the timeout as a function of
RTT.
• SampleRTT – time difference between sending data and receiving ACK.
EstimatedRTT = (α * EstimatedRTT) + ((1- α) * SamleRTT)
α – used to smooth the Estimated RTT. a between 0.8 and 0.9
Timeout = 2 * EstimatedRTT
3. Adaptive Retransmission
Karn / Partridge Algorithm:
When a segment is retransmitted and then an ACK arrives at
the sender
• It is impossible to decide if this ACK should be associated with the first or the
second transmission for calculating RTTs.
Associating the ACK with (a) original transmission versus (b)
retransmission
4. Adaptive Retransmission
To solve this problem,
- Do not sample RTT when retransmitting.
- Only measures SampleRTT for segment that have been sent only once.
- It uses Exponential backoff for timeout selection. i.e., Double the
timeout after each retransmission.
Jacobson / Karela Algorithm
Difference = SampleRTT − EstimatedRTT
EstimatedRTT = EstimatedRTT + (δ × Difference)
Deviation = Deviation + δ * (|Difference| − Deviation)
TimeOut = μ × EstimatedRTT + ϕ × Deviation
where based on experience, μ is typically set to 1 and ϕ is set to 4. Thus, when
the variance is small, TimeOut is close to EstimatedRTT; a large variance causes
the deviation term to dominate the calculation.
