This document outlines the syllabus for a course on computer networks. It covers three units: introduction to networking concepts and reference models, the data link layer, and the network layer. The data link layer section describes its design issues, functions, services, framing, error control, and flow control. It also discusses error detection techniques like vertical redundancy checks, longitudinal redundancy checks, cyclic redundancy checks, and checksums. The document provides examples and diagrams to explain these concepts.
The data link layer, or layer 2, is the second layer of the seven-layer OSI model of computer networking. This layer is the protocol layer that transfers data between adjacent network nodes in a wide area network (WAN) or between nodes on the same local area network (LAN) segment.
The data link layer, or layer 2, is the second layer of the seven-layer OSI model of computer networking. This layer is the protocol layer that transfers data between adjacent network nodes in a wide area network (WAN) or between nodes on the same local area network (LAN) segment.
About types of errors, Error detection and its types -vertical redundancy check, Longitudinal redundancy check, cyclic redundancy check, checksum, example ,Error correction using Hamming code
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The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
About types of errors, Error detection and its types -vertical redundancy check, Longitudinal redundancy check, cyclic redundancy check, checksum, example ,Error correction using Hamming code
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
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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.
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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.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
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Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
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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.
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In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
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This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Final project report on grocery store management system..pdf
Chapter 2.1.1.pptx
1. DISCOVER . LEARN . EMPOWER
University Institute of Engineering
DEPARTMENT OF COMPUTER SCIENCE
& ENGINEERING
Bachelor of Engineering (Computer Science & Engineering)
Subject Name:Computer Network
Subject Code: 21CSH-256/ 21ITH-256
2. Syllabus
UNIT-I [15h]
Introduction: Introduction to network, types of transmission technologies, Network Categories: LAN, MAN, WAN (Wireless /Wired),
Network Software: Concept of Layers, Protocols, interfaces and services. Reference Models: OSI, TCP/IP and comparison, Concept of
Topologies.
Physical Layer: Bit rate, Baud rate, Bandwidth, Transmission Impairments: Attenuation, Distortion, Noise; Data rate limits: Nyquist
formula, Shannon Formula, Modulation & modems; Transmission Modes, Multiplexing: Frequency Division, Time Division, Wavelength
Division; Transmission Media: Twisted pair, coaxial, fiber optics, Wireless Transmission (radio, microwave & infrared);Message
switching, Circuit Switching & Packet Switching.
UNIT-II
[15h]
Data Link Layer: Design issues, Error Detection & Correction; Flow control & Error Control; Sliding Window Protocols, ARQ: Stop &
Wait , Go Back n, Selective Repeat ; Examples of DLL protocols – HDLC, PPP; Medium Access Sub layer: Channel Allocation; Random
Access: ALOHA, CSMA protocols; Controlled Access: Polling, Reservation, Token Passing; Examples of IEEE
standards(802.2,802.3,802.4, 802.5), Basics of Wi-Fi(802.11).Network Layer: Design issues, Logical Addressing: IPv4 & IPv6; Packet
Formats & their comparison IPv4 & IPv6; Routing Algorithms: Distance Vector, Link State
UNIT-III [15h]
Network Layer(Continue): Congestion Control: Principles of congestion control; Congestion prevention policies, Leaky bucket & Token
Bucket Algorithms.
Transport Layer: Services provided to upper layers, Elements of Transport protocols. Addressing, Flow Control & buffering; Example
Transport protocols: TCP, SCTCP & UDP.
Application Layer and Network Security: Domain Name System, Simple Network Management Protocol, Electronic Mail, World Wide
Web, Basics of authentication, Public and Private Key Cryptography, Digital Signatures and Certificates, Firewalls. 2
3. Course Objectives
3
CO1 Interpret the building block of network and its architecture
CO2 Demonstrate the services of all the layers of network models
CO3 Identify and analyze error and control flow mechanism.
CO4 Explain various routing protocols of network models to ensure robust delivery of messages
CO5 Exemplify the securities of computer network
8. Functions of the Data Link Layer (2)
Relationship between packets and frames.
9. Services Provided to Network Layer
(a) Virtual communication.
(b) Actual communication.
10. The data link layer can be designed to offer various
services
•Unacknowledged connectionless service.
•Acknowledged connectionless service.
•Acknowledged connection-oriented service
•Unacknowledged connectionless service consists of
having the source machine send independent frames to
the destination machine without having the destination
machine acknowledge them.
• No logical connection is established beforehand or
released afterward.
11. • This class of service is appropriate when the error rate is
very low so that recovery is left to higher layers. It is also
appropriate for real-time traffic, such as voice.
• The next step up in terms of reliability is acknowledged
connectionless service.
• When this service is offered, there are still no logical
connections used, but each frame sent is individually
acknowledged.
• In this way, the sender knows whether a frame has arrived
correctly. If it has not arrived within a specified time
interval, it can be sent again.
12. • When connection-oriented service is used, transfers go
through three distinct phases.
• In the first phase, the connection is established by having
both sides initialize variables and counters needed to
keep track of which frames have been received and which
ones have not.
• In the second phase, one or more frames are actually
transmitted.
• In the third and final phase, the connection is released,
freeing up the variables, buffers, and other resources
used to maintain the connection
13. • The usual approach is for the data link layer to break the
bit stream up into discrete frames and compute the
checksum for each frame.
• When a frame arrives at the destination, the checksum is
recomputed.
• If the newly-computed checksum is different from the
one contained in the frame, the data link layer knows
that an error has occurred and takes steps to deal with it
(e.g., discarding the bad frame and possibly also sending
back an error report).
15. Framing (2)
(a) A frame delimited by flag bytes.
(b) Four examples of byte sequences before and after stuffing.
16. Framing (3)
Bit stuffing
(a) The original data.
(b) The data as they appear on the line.
(c) The data as they are stored in receiver’s memory after
destuffing.
17. • The following character encoding is used in a data link
protocol: A: 01000111; B: 11100011; FLAG: 01111110; ESC:
11100000 Show the bit sequence transmitted (in binary) for
the four-character frame: A B ESC FLAG when each of the
following framing methods are used:
• (a) Character count.
• (b) Flag bytes with byte stuffing.
• (c) Starting and ending flag bytes, with bit stuffing.
19. • The following data fragment occurs in the middle of a
data stream for which the byte-stuffing algorithm
described in the text is used: A B ESC C ESC FLAG FLAG D.
What is the output after stuffing?
• A bit string, 0111101111101111110, needs to be
transmitted at the data link layer. What is the string
actually transmitted after bit stuffing?
20. Error Correction
It can be handled in two ways:
1) receiver can have the sender retransmit the entire data unit.
2) The receiver can use an error-correcting code, which automatically
corrects certain errors.
23. Basic concepts
Networks must be able to transfer data from one
device to another with complete accuracy.
Data can be corrupted during transmission.
For reliable communication, errors must be detected
and corrected.
Error detection and correction are
implemented either at the data link layer or
the transport layer of the OSI model.
26. Single bit errors are the least likely type of errors
in serial data transmission because the noise
must have a very short duration which is very
rare. However this kind of errors can happen in
parallel transmission.
Example:
If data is sent at 1Mbps then each bit lasts only
1/1,000,000 sec. or 1 μs.
For a single-bit error to occur, the noise must
have a duration of only 1 μs, which is very rare.
29. The term burst error means that two or more
bits in the data unit have changed from 1 to 0 or
from 0 to 1.
Burst errors does not necessarily mean that the
errors occur in consecutive bits, the length of
the burst is measured from the first corrupted bit
to the last corrupted bit. Some bits in between
may not have been corrupted.
30. Burst error is most likely to happen in serial
transmission since the duration of noise is normally
longer than the duration of a bit.
The number of bits affected depends on the data rate
and duration of noise.
Example:
If data is sent at rate = 1Kbps then a noise of 1/100 sec
can affect 10 bits.(1/100*1000)
If same data is sent at rate = 1Mbps then a noise of
1/100 sec can affect 10,000 bits.(1/100*106)
31. Error detection
Error detection means to decide whether the received
data is correct or not without having a copy of the
original message.
Error detection uses the concept of redundancy, which
means adding extra bits for detecting errors at the
destination.
38. Performance
LRC increases the likelihood of detecting
burst errors.
If two bits in one data units are damaged
and two bits in exactly the same positions in
another data unit are also damaged, the
LRC checker will not detect an error.
41. Cyclic Redundancy Check
• Given a k-bit frame or message, the transmitter
generates an n-bit sequence, known as a frame
check sequence (FCS), so that the resulting
frame, consisting of (k+n) bits, is exactly divisible
by some predetermined number.
• The receiver then divides the incoming frame by
the same number and, if there is no remainder,
assumes that there was no error.
50. At the sender
The unit is divided into k sections, each of n bits.
All sections are added together using one’s complement to get the
sum.
The sum is complemented and becomes the checksum.
The checksum is sent with the data
51. At the receiver
The unit is divided into k sections, each of n bits.
All sections are added together using one’s complement to get the
sum.
The sum is complemented.
If the result is zero, the data are accepted: otherwise, they are
rejected.
52. Performance
The checksum detects all errors involving an odd
number of bits.
It detects most errors involving an even number of
bits.
If one or more bits of a segment are damaged and
the corresponding bit or bits of opposite value in a
second segment are also damaged, the sums of those
columns will not change and the receiver will not
detect a problem.
53. Error Correction
It can be handled in two ways:
1) receiver can have the sender retransmit the entire data unit.
2) The receiver can use an error-correcting code, which automatically
corrects certain errors.
54. Single-bit error correction
To correct an error, the receiver reverses the
value of the altered bit. To do so, it must know
which bit is in error.
Number of redundancy bits needed
• Let data bits = m
• Redundancy bits = r
Total message sent = m+r
The value of r must satisfy the following relation:
2r ≥ m+r+1